International Journal of Pharmaceutics (v.517, #1-2)

Display OmittedThe primary purpose of the present study was to design and optimize a liposomal formulation of the poorly water-soluble drug oleanolic acid (OA) to improve its oral bioavailability, and prolong the duration of therapeutic drug level. Liposomes containing a soybean lecithin and cholesterol lipid bilayer, a protective hydrophilic polyvinylpyrrolidone-K30 (PVP-K30) coating, and a protective bile salt, sodium deoxycholate, were prepared by a thin-film dispersion method coupled with sonication. Several properties of the PVP-modified OA liposomes (PVPOALs), including surface morphology, particle size, zeta potential and entrapment efficiency were extensively characterized. The pharmacokinetic parameters of PVPOALs in rats were determined by UPLC–MS/MS following oral administration. The results of the characterization studies demonstrated that PVPOALs were spherical particles with an average particle size of 179.4 nm and a zeta potential of −28.8 mV. The drug encapsulation efficiency was more than 90%. After freeze-drying, the prepared liposomes possessed high entrapment efficiency of more than 90%. The mean particle size was 194.8 nm, and the zeta potential was about −30.9 mV. Furthermore, as compared to the commercial tablets, the liposomal formulation enhanced the maximum plasma concentration (C max) of OA by 6.90-fold in rat plasma. The relative bioavailability of PVP-modified liposomes was 607.9%. The research work in the paper suggests that PVP-modified liposomes could serve as a practical oral preparation for OA in future cancer therapy.
Keywords: Oleanolic acid; Liposomes; Polyvinylpyrrolidone; Sodium deoxycholate; Bioavailability;

Evaluation of highly branched cyclic dextrin in inhalable particles of combined antibiotics for the pulmonary delivery of anti-tuberculosis drugs by Kazunori Kadota; Arisa Senda; Hideaki Tagishi; John Oluwasogo Ayorinde; Yuichi Tozuka (8-18).
Display OmittedThis work aims to identify a suitable formulation for the pulmonary delivery of combinations of inhalational drugs using highly branched cyclic dextrin (HBCD) macromolecules. We compared the effectiveness between powders prepared from HBCD with those prepared from five alternative excipients (lactose, maltose, sucrose, β-cyclodextrin and methyl β-cyclodextrin) in the pulmonary delivery of a single-dosage form of two anti-tuberculosis drugs (isoniazid and rifampicin).Fine particles of untreated active pharmaceutical ingredients (APIs) and combination products using excipients were prepared by spray drying. Rifampicin, a hydrophobic compound, was dissolved in ethanol, whereas isoniazid, a hydrophilic compound combined with either HBCD or an alternative excipient was dissolved in water. This was followed by the preparation of the spray-dried particle formulations (SDPs). The SDPs were characterised in terms of particle size, surface morphology, drug content, specific surface area, powder X-ray diffraction and inhalational properties.The addition of either an excipient or HBCD decreased API particle sizes, producing submicron-size particles. Surface morphology examination using scanning electron microscopy revealed API SDPs to be cylindrical and non-wrinkled. However, API–excipient SDPs were wrinkled and rough. Only HBCD SDPs were porous and non-aggregating, thereby suggesting superior aerodynamic properties and suitability for pulmonary delivery of these particles. HBCD formulations had the highest drug content in terms of both isoniazid (97.5%) and rifampicin (92.3%). Larger surface areas were obtained for SDPs of HBCD than those of other sugars. Regarding inhalational properties, HBCD formulations had higher emitted dose and fine-particle fractions than formulations of all other sugars tested. Our results confirm the feasibility of the formulation of hydrophilic and hydrophobic drug substances into a single-dosage preparation for pulmonary delivery using HBCD as an excipient.
Keywords: Highly branched polymer; Rifampicin; Isoniazid; Porous particles; Dry powder inhalers; Spray-drying; Sugars;

Predicting optimal wet granulation parameters for extrusion-spheronisation of pharmaceutical pellets using a mixer torque rheometer by Manuel Kuhs; John Moore; Gayathri Kollamaram; Gavin Walker; Denise Croker (19-24).
Display OmittedMixer torque rheometry (MTR) was evaluated as a pre-production (pre-formulation and optimization) tool for predicting ideal liquid-to-solid ratios (L/S) for extrusion-spheronisation of a wide range of APIs using 10 g formulations. APIs of low, medium and high solubility were formulated at low and high loadings (15 and 40% w/w, respectively) with PVP as binder (5%) and MCC as the major excipient. L/S corresponding to the maximum torque produced during wet massing in the MTR, L/S (maxT), was 0.8 for the low solubility APIs, which decreased to 0.6 for some of the more soluble APIs, especially at high loadings. Formulations extruded-spheronised at L/S maxT) produced pellets of acceptable size (between 900 and 1400 um) for all formulations, but mostly of unacceptable shape (dumb-bells of aspect ratio 1.2). Increasing L/S by 25% successfully produced spherical or near-spherical (aspect ratio 1.1) pellets for all formulations except one of the highly soluble APIs (piracetam) at high loading. Overall, MTR was demonstrated to be a useful pre-formulation and optimization tool in extrusion-spheronisation.
Keywords: Pre-formulation; Mixer torque rheometry; Extrusionspheronisation; Wet granulation; Liquid-solid ratio;

Fabrication of self-assembled chitosan-dispersed LDL nanoparticles for drug delivery with a one-step green method by Jing Tian; Shasha Xu; Hongbing Deng; Xinxing Song; Xiujuan Li; Jiajia Chen; Feng Cao; Bin Li (25-34).
Display OmittedSelf-assembled nanoparticles (NPs) composed of chitosan (CS) and low density lipoprotein (LDL) of hen eggs were prepared by a one-step green synthesis of mixing CS solution and LDL suspension. The formulated CS-LDL NPs were then applied to encapsulate doxorubicin hydrochloride (DOX) with the encapsulation efficiency of 51.7%. The average particle size and ζ-potential of DOX-loaded CS-LDL NPs (CS-LDL-DOX NPs) were 179 nm and +48.3 mV, respectively. The encapsulated DOX showed less cytotoxicity than free DOX after 24-h incubation with gastric cancer SGC7901 cells, which may be due to extended release. Cellular uptake of CS-LDL-DOX NPs was significant higher than that of free DOX due to the endocytosis of tumor cells. Thus CS-LDL-DOX NPs showed a potential in reducing cytotoxicity of DOX by extended release behavior and preferential uptake compared to free DOX. In addition, flow cytometry and terminal-deoxynucleotidyl-transferase-mediated dUTP nick-end labeling assay demonstrated that CS-LDL-DOX NPs induced the apoptosis of cancer cells. Autophagy was involved in effects caused by CS-LDL-DOX NPs through blocking AKT/mTOR signaling, which was demonstrated by the analyses of the expression of LC3, p62, AKT, p-AKT, mTOR and p-mTOR.
Keywords: Low-density lipoprotein; Chitosan; Self-assembly; Nanocarrier;

Display OmittedPhospholipase A2 (PLA2) is expressed in inflammation-related tissue, including cancer tumors. We report that a hybrid liposome composed of phospholipid (DPPC) and PEGylated block-copolymer (Poloxamer 188) can rapidly release an encapsulated hydrophilic drug in the presence of PLA2. DPPC/P188 liposomes released approximately 80% of the encapsulated calcein (a fluorescence marker) within 10 min in the presence of 120 mU of PLA2 at 37 °C in vitro, whereas several other liposomal compositions used for inhalation therapy did not. DPPC/P188 liposomes were stable in the absence of PLA2 at 37 °C after 60 min incubation and drug release by PLA2 was dependent on the amount of P188 incorporated into the DPPC liposomes. Drug release from doxorubicin (DOX, anticancer drug)-loaded DPPC/P188 liposomes was facilitated at higher PLA2 concentrations and was dependent on the temperature and the presence of calcium ion, thus partially explaining PLA2-responsive drug release. DOX release from liposomes triggered by PLA2 exhibited the same cytotoxic effects on the A549 lung cancer cell line as did DOX in free solution. These findings suggest that DPPC/P188 liposomes are a promising drug carrier for delivering drug efficiently at PLA2-expressing sites such as inflammatory lung cancer.
Keywords: Liposome; Phospholipase A2; Inhalation formulation; Poloxamer; Triggered release; Lung cancer;

Display OmittedOral delivery of pharmaceuticals requires that they retain their physical and chemical attributes during transit within the gastrointestinal (GI) tract, for the manifestation of desired therapeutic profiles. Solid lipid nanoparticles (SLNs) are used as carriers to improve the absorption of hydrophobic drugs. In this study, we examine the stability of amphotericin B (AmB) and paracetamol (PAR) SLNs in simulated GI fluids during gastric emptying. On contact with the simulated fluids, the particles increased in size due to ingress of the dissolution media into the particles. Simulated gastric emptying revealed that the formulations had mean sizes <350 nm and neutral surface charges, both of which are optimal for intestinal absorption of SLNs. There was ingress of the fluids into the SLNs, followed by diffusion of the dissolved drug, whose rate depended on the solubility of the loaded-drug in the particular medium. Time-of-flight secondary ion mass spectrometry analyses indicated that drug loading followed the core-shell model and that the AmB SLNs have a more drug-enriched core than the PAR SLNs do. The AmB SLNs are therefore a very suitable carrier of AmB for oral delivery. The stability of the SLNs in the simulated GI media indicates their suitability for oral delivery.
Keywords: Solid lipid nanoparticle; Stability; Gastrointestinal tract; Gastric emptying; Amphotericin B; Paracetamol;

Effect of the oral administration of nanoencapsulated quercetin on a mouse model of Alzheimer’s disease by Lina Clara Gayoso e Ibiapina Moreno; Elena Puerta; José Eduardo Suárez-Santiago; Nereide Stela Santos-Magalhães; Maria J. Ramirez; Juan M. Irache (50-57).
Display OmittedQuercetin has been identified as a promising compound with a neuroprotective potential against age-related neurodegenerative diseases such as Alzheimer's disease (AD). Nevertheless, the clinical application of quercetin is hampered by its low oral bioavailability. The aim of this work was to evaluate the capability of nanoencapsulated quercetin in zein nanoparticles (NPQ), that significantly improves the oral absorption and bioavailability of the flavonoid, as potential oral treatment for AD. For this purpose, SAMP8 mice were orally treated for two months with either NPQ (25 mg/kg every 48 h) or a solution of quercetin (Q; 25 mg/kg daily). NPQ displayed a size of 260 nm and a payload of about 70 μg/mg. For Q, no significant effects were observed in animals. On the contrary, the oral administration of NPQ improved the cognition and memory impairments characteristics of SAMP8 mice. These observations appeared to be related with a decreased expression of the hippocampal astrocyte marker GFAP. Furthermore, significant levels of quercetin were quantified in the brain of mice treated with nanoparticles. These findings highlight the potential of zein nanoparticles to promote the oral absorption of quercetin as well as the therapeutic potential of this flavonoid in AD pathogenesis.
Keywords: Quercetin; Nanoparticles; SAMP8 mice; Oral delivery; Alzheimer’s disease;

Layer-by-layer nanoparticle platform for cancer active targeting by Min Sung Suh; Jie Shen; Liisa T. Kuhn; Diane J. Burgess (58-66).
Display OmittedNanoparticles as drug delivery carriers have been investigated over the last few decades, particularly for cancer treatment. The rationale in developing such nanoparticles is to maximize drug efficacy while minimizing toxic side effects. This can be most effectively achieved through target specific drug delivery. A novel biocompatible nanoparticle platform prepared using the core-shell self-assembly technique is reported. The core consists of calcium phosphate which is biocompatible and pH-sensitive, and the shell is composed of biocompatible polymers (hyaluronic acid, CD44 targeting moiety; and chitosan, physical cross-linker). Cisplatin was selected as a model drug and incorporated between the core and the shell. The nanoparticle composition was optimized for high serum stability and low protein binding. These nanoparticles demonstrated target specific delivery in human lung cancer cells (which overexpress CD44 receptors). The targeting ability of the nanoparticles was confirmed with an 8-fold increase of drug efficacy (IC50) compared to cisplatin. Furthermore, the pH-sensitive core of the nanoparticle platform led to controlled drug release through destabilization in acidic conditions. This platform technology provides a simple approach for the design of targeted biocompatible nanoparticles for cancer therapy.
Keywords: Nanoparticles; Platform; CD44; pH-sensitive; Targeted cancer therapy;

Display OmittedThe main concerns with drugs designed for oral administration are their inactivation or degradation in the harsh conditions of the gastrointestinal tract, their poor solubility through the gastrointestinal mucus gel layer, the poor intestinal epithelium permeability that limits their absorption, and their toxicity. In this context, poly(anhydride) nanoparticles are capable of protecting the drug from the harsh environment, reduce the drug’s toxicity and, by virtue of surface modification, to enhance or reduce their mucus permeability and the bioadhesion to specific target cells.The copolymer between methyl vinyl ether and maleic anhydride (commercialized as Gantrez® AN 119) are part of the poly(anhydride) nanoparticles. These biocompatible and biodegradable nanoparticles (NPs) can be modified by using different ligands. Their usefulness as drug carriers and their bioadhesion with components of the intestinal mucosa have been described. However, their toxicity, genotoxicity and mucus permeation capacity has not been thoroughly studied.The aim of this work was to evaluate and compare the in vitro toxicity, cell viability and in vitro genotoxicity of the bioadhesive empty Gantrez® AN 119 NPs modified with dextran, aminodextran, 2-hydroxypropyl-β-cyclodextrin, mannosamine and poly-ethylene glycol of different molecular weights.Results showed that, in general, coated NPs exhibit better mucus permeability than the bare ones, those coated with mannosamine being the most permeable ones. The NPs studied did not affect cell metabolism, membrane integrity or viability of Caco-2 cells at the different conditions tested. Moreover, they did not induce a relevant level of DNA strand breaks and FPG-sensitive sites (as detected with the comet assay).
Keywords: Polymeric nanoparticles; Cytotoxicity; Viability; Genotoxicity; Comet assay; Mucus permeation;

Strategy for assessment of the colloidal and biological stability of H1N1 influenza A viruses by Frank Hämmerling; Oliver Lorenz-Cristea; Pascal Baumann; Jürgen Hubbuch (80-87).
Display OmittedCurrent influenza vaccines are mostly formulated as liquids which requires a continuous cold chain to maintain the stability of the antigen. For development of vaccines with an increased stability at ambient temperatures, manifold parameters and their influences on the colloidal stability and activity of the antigen have to be understood. This work presents a strategy to examine both, the colloidal stability and the remaining biological activity of H1N1 influenza viruses under various conditions after an incubation of 40 days. H1N1 phase diagrams were generated for several pH values and different initial H1N1 and NaCl concentrations. It was shown that the highest H1N1 recoveries were obtained for pH 6 and that moderate amounts of NaCl are favorable for increased recoveries. In contrast to colloidal stability, the highest remaining HA activity was observed at pH 9. The electrostatic and hydrophobic surface properties of H1N1 were investigated to reveal the mechanisms accounting for the decrease in stability. Secondly, the capability of virus precipitation by polyethylene glycol in combination with determination of surface hydrophobicity was proven to be useful as a predictive tool to rank stability under different conditions. This methodology enables the rapid assessment of aggregation propensity of H1N1 formulations and the influence on the activity of the virus particles and might become a standard tool during the development of vaccine formulations.
Keywords: Pandemic influenza virus; Stability; Surface properties; Formulation; Virus phase diagram;

The use of partially hydrolysed polyvinyl alcohol for the production of high drug-loaded sustained release pellets via extrusion-spheronisation and coating: In vitro and in vivo evaluation by G. Verstraete; W. De Jaeghere; J. Vercruysse; W. Grymonpré; V. Vanhoorne; F. Stauffer; T. De Beer; A. Bezuijen; J.P. Remon; C. Vervaet (88-95).
Display OmittedPartially hydrolysed polyvinyl alcohol (PVA) was evaluated as a pelletisation aid for the production of pellets with a high acetaminophen and metformin hydrochloride concentration (>70%, w/w). Mixtures with varying drug concentration and PVA/microcrystalline cellulose (MCC) ratios were processed via extrusion-spheronisation, either after addition of PVA as a dry powder or as an aqueous solution. Finally, high drug- loaded metformin pellets were coated with a methacrylic acid copolymer (Eudragit™ NM 30D) and evaluated for their sustained release potency in vitro and in vivo. The plasticity index of the wet mass increased by the addition of PVA to the formulation, which resulted in enhanced extrusion-spheronisation properties, even at a high drug load. Although the MCC concentration was successfully lowered by adding PVA, the inclusion of MCC in the formulation was essential to overcome problems related to the tackiness effect of PVA during extrusion. Overall, wet addition of PVA was superior to dry addition, as pellets with a higher mechanical strength and narrower particle size distribution were obtained. Pellets containing 87% (w/w) metformin hydrochloride were successfully layered with 20% (w/w) coating material, yielding sustained release pellets with a final drug load of 70% (w/w). In addition, the sustained release characteristics of the PVA-based pellets with a high drug content were confirmed in vivo as no difference with the Glucophage™ SR reference formulation was observed.
Keywords: Extrusion-spheronisation; Pelletisation aid; Polyvinyl alcohol; High drug load; Pellets; Sustained release;

In vitro inhibition of Clostridium difficile by commercial probiotics: A microcalorimetric study by Mansa Fredua-Agyeman; Paul Stapleton; Abdul W. Basit; Anthony E. Beezer; Simon Gaisford (96-103).
Display OmittedThe aim of the study was to investigate the influence of some commercial probiotics on the growth of Clostridium difficile using isothermal microcalorimetry, a technique which can monitor the real time growth of bacteria. Commercial probiotic strains and products, Lactobacillus acidophilus LA-5®, Bifidobacterium lactis BB-12®, Probio 7® and Symprove™ were co-cultured with C. difficile in Brain Heart Infusion (BHI) broth supplemented with 0.1% (w/v) l-cysteine hydrochloride and 0.1% (w/v) sodium taurocholate and monitored in the microcalorimeter. Pseudomonas aeruginosa NCIMB 8628 was also co-cultured with C. difficile and studied. The results indicated inhibition of C. difficile by the probiotics. The inhibition of C. difficile was shown to be pH-dependent using neutralized and unmodified cell free supernatant (CFS) produced by the probiotic strains. However, concentrated CFS of the probiotics also inhibited the intestinal pathogen in a non pH-dependent manner, likely due to specific antimicrobial substances produced. The results also indicated that C. difficile growth was greatly influenced by the presence of sodium taurocholate and by the pH of the medium. A medium pH of between 6.45 and 6.9 demonstrated maximum growth of the organism in the microcalorimeter.
Keywords: Clostridium difficile; Probiotics; Inhibition; Isothermal microcalorimetry; Co-culture;

Transdermal therapeutic systems for memantine delivery. Comparison of passive and iontophoretic transport by S. del Río-Sancho; C.E. Serna-Jiménez; M. Sebastián-Morelló; M.A. Calatayud-Pascual; C. Balaguer-Fernández; A. Femenía-Font; Y.N. Kalia; V. Merino; A. López-Castellano (104-111).
Display OmittedMemantine is a non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist used in the treatment of moderate to severe dementia including the symptoms of Alzheimer’s disease (AD). It is administered orally but compliance, swallowing problems and the routine use of multiple medications in elderly AD patients means that an alternative route of administration would be of interest.The aim of the present study was to develop memantine hydrochloride occlusive transdermal therapeutic systems (TTS) for passive and iontophoretic delivery across the skin. Polyvinyl pyrrolidone (PVP) and a mixture with polyvinyl alcohol (PVA) were employed as polymeric matrices. The study involved the TTS characterization in addition to quantification of the memantine transport across porcine skin in vitro.The evaluation of the TTS physical properties suggested that systems were made more mechanically resistant by including PVA (6%) or high concentrations of PVP (24%). Moreover, a linear correlation was observed between the concentration of PVP and the bioadhesion of the systems. Drug delivery experiments showed that the highest transdermal flux provided by a passive TTS (PVP 24% w/w limonene) was 8.89 ± 0.81 μg cm−2  h−1 whereas the highest iontophoretic transport was 46.4 ± 3.6 μg cm−2  h−1. These innovative TTS would enable two dosage regimens that could lead to therapeutic plasma concentrations.
Keywords: Memantine; Transdermal delivery; Occlusive-systems; Chemical penetration enhancers; Iontophoresis;

Display OmittedThe clear identification of drug products by the patients is essential for a safe and effective medication management. In order to understand the impact of shape, size and color on medication identification a study was performed in subjects with type 2 diabetes mellitus (T2D). Ten model drugs differentiated by shape, size and color were evaluated using a mixed method of medication schedule preparation by the participants followed by a semi-structured interview. Detection times were fastest for the large round tablet shape and the bi-chromatic forms. Larger size was easier to identify than the smaller sizes except for the bi-chromatic forms. The shape was the major source of errors, followed by the size and the color dimension. The results from this study suggests that color as a single dimension are perceived more effectively by subjects with T2D compared to shape and size, which requires a more demanding processing of three dimension and is dependent on the perspective.
Keywords: Medicine identification; Medication error; Product differentiation; Drug recognition; Effectiveness; Drug safety;

Elucidation and visualization of solid-state transformation and mixing in a pharmaceutical mini hot melt extrusion process using in-line Raman spectroscopy by Jeroen Van Renterghem; Ashish Kumar; Chris Vervaet; Jean Paul Remon; Ingmar Nopens; Yvan Vander Heyden; Thomas De Beer (119-127).
Display OmittedMixing of raw materials (drug + polymer) in the investigated mini pharma melt extruder is achieved by using co-rotating conical twin screws and an internal recirculation channel. In-line Raman spectroscopy was implemented in the barrels, allowing monitoring of the melt during processing. The aim of this study was twofold: to investigate (I) the influence of key process parameters (screw speed – barrel temperature) upon the product solid-state transformation during processing of a sustained release formulation in recirculation mode; (II) the influence of process parameters (screw speed – barrel temperature – recirculation time) upon mixing of a crystalline drug (tracer) in an amorphous polymer carrier by means of residence time distribution (RTD) measurements. The results indicated a faster mixing endpoint with increasing screw speed. Processing a high drug load formulation above the drug melting temperature resulted in the production of amorphous drug whereas processing below the drug melting point produced solid dispersions with partially amorphous/crystalline drug. Furthermore, increasing the screw speed resulted in lower drug crystallinity of the solid dispersion. RTD measurements elucidated the improved mixing capacity when using the recirculation channel. In-line Raman spectroscopy has shown to be an adequate PAT-tool for product solid-state monitoring and elucidation of the mixing behavior during processing in a mini extruder.
Keywords: Hot-melt extrusion; Raman spectroscopy; Solid-state transformation; Residence time distribution; Mixing; Transport; Recirculation time;

Learning from patients: Identifying design features of medicines that cause medication use problems by Kim Notenboom; Hubert GM Leufkens; Herman Vromans; Marcel L Bouvy (128-134).
Display OmittedUsability is a key factor in ensuring safe and efficacious use of medicines. However, several studies showed that people experience a variety of problems using their medicines. The purpose of this study was to identify design features of oral medicines that cause use problems among older patients in daily practice. A qualitative study with semi-structured interviews on the experiences of older people with the use of their medicines was performed (n = 59). Information on practical problems, strategies to overcome these problems and the medicines’ design features that caused these problems were collected. The practical problems and management strategies were categorised into ‘use difficulties’ and ‘use errors’. A total of 158 use problems were identified, of which 45 were categorized as use difficulties and 113 as use error. Design features that contributed the most to the occurrence of use difficulties were the dimensions and surface texture of the dosage form (29.6% and 18.5%, respectively). Design features that contributed the most to the occurrence of use errors were the push-through force of blisters (22.1%) and tamper evident packaging (12.1%). These findings will help developers of medicinal products to proactively address potential usability issues with their medicines.
Keywords: Medication use; Usability; Use errors; Medicinal product design; Packaging; Older patients;

Thermosensitive nanofibers loaded with ciprofloxacin as antibacterial wound dressing materials by Heyu Li; Gareth R. Williams; Junzi Wu; Yao Lv; Xiaozhu Sun; Huanling Wu; Li-Min Zhu (135-147).
Display OmittedTo obtain wound dressings which could be removed easily without secondary injuries, we prepared thermoresponsive electrospun fiber mats containing poly(di(ethylene glycol) methyl ether methacrylate) (PDEGMA). Blend fibers of PDEGMA and poly(l-lactic acid-co-ε-caprolactone) (P(LLA-CL) were fabricated via electrospinning, and analogous fibers containing the antibiotic ciprofloxacin (CIF) were also prepared. Smooth cylindrical fibers were obtained, albeit with a small amount of beading visible for the ciprofloxacin-loaded fibers. X-ray diffraction showed the drug to exist in the amorphous physical form post-electrospinning. The composite fibers showed distinct thermosensitive properties and gave sustained release of CIF over more than 160 h in vitro. The fibers could promote the proliferation of fibroblasts, and by varying the temperature cells could easily be attached to and detached from the fibers. Antibacterial tests demonstrated that fibers loaded with ciprofloxacin were effective in inhibiting the growth of E. coli and S. aureus. In vivo investigations on rats indicated that the composite PDEGMA/P(LLA-CL) fibers loaded with CIF had much more potent wound healing properties than a commercial gauze and CIF-loaded fibers made solely of P(LLA-CL). These results demonstrate the potential of PDEGMA/P(LLA-CL)/ciprofloxacin fibers as advanced wound dressing materials.
Keywords: Thermosensitive; PDEGMA; P(LLA-CL); Ciprofloxacin; Electrospinning; Wound dressing;

Display OmittedThe study investigated the effects of different combined top-down and bottom-up nanocrystallization technologies on particle size and solid state of avanafil nanoparticles. Combined antisolvent precipitation-ultrasonication (sonoprecipitation) technique was adopted to prepare 18 formulas according to 32.21 factorial design using 3 stabilizers; Tween 80, polyvinyl alcohol (PVA) and Pluronic F68 at different concentrations with different cryoprotectants. Particle size analysis of the lyophilized formulas showed that Tween 80 was an effective nanoparticles stabilizer in contrast to Pluronic F68 and PVA which failed to prevent nanoparticles flocculation when they were used at high concentration. The combined effects of nanonization and amorphism contributed to the improvement in solubility. Further processing of the sonoprecipitated formulas by high pressure homogenization (HPH) (modified NANOEDGE™ technology) resulted in further size reduction of PVA-stabilized particles, while it stimulated flocculation of Tween-stabilized nanoparticles. Nevertheless, all of the homogenized formulas partially retrieved their crystallinity which reduced their solubility. Non-homogenized formula 2E composed of 1:2 (avanafil: Tween) with glucose as cryoprotectant, exhibited 13.68- and 2.59-fold improvement in solubility and in vitro dissolution, respectively. This formula had oral bioavailability of 137.02% relative to Spedra® tablets and it maintained its nanosize, amorphism and dissolution behavior over 6 months of storage under stress conditions.
Keywords: Crystallinity; Amorphism; Solubility; Stabilizer; Lyophilization;

Effective targeting of gemcitabine to pancreatic cancer through PEG-cored Flt-1 antibody-conjugated dendrimers by Kıvılcım Öztürk; Güneş Esendağlı; Mustafa Ulvi Gürbüz; Metin Tülü; Sema Çalış (157-167).
Display OmittedTumor-targeted delivery of anticancer drugs using dendrimers has been recognized as a promising strategy to increase efficiency and reduce adverse effects of chemotherapy. Herein, we developed a dendrimer-based drug delivery system targeting Flt-1 (a receptor for vascular endothelial growth factors (VEGF)) receptor to improve therapeutic efficacy of gemcitabine in pancreatic cancer. Synthesized polyethylene glycol (PEG)-cored PAMAM dendrimers, which bear anionic carboxylic acid groups on the surface were modified with PEG chains, which were then conjugated with Flt-1 antibody. Following structural and chemical characterization studies, gemcitabine HCl-dendrimer inclusion complexes were successfully prepared. These complexes were efficiently engulfed by Flt-1 expressing pancreatic cancer cells, which enhanced the cytotoxicity of gemcitabine. Moreover, pancreatic tumors established in mice were highly targeted by PEG-cored Flt-1 antibody-conjugated dendrimers and increased accumulation of these gemcitabine-loaded complexes exhibited satisfactory in vivo anti-cancer efficacy. In conclusion, dendrimer-based targeted delivery of chemotherapeutics may serve as a promising approach for the treatment of malignancies such as pancreatic cancer that do not benefit from conventional chemotherapy.
Keywords: Dendrimers; Pancreatic cancer; Targeted drug delivery; Gemcitabine; Cell culture; Tumor-bearing mice;

Albumin nanoparticles for glutathione-responsive release of cisplatin: New opportunities for medulloblastoma by Giuseppina Catanzaro; Manuela Curcio; Giuseppe Cirillo; Umile Gianfranco Spizzirri; Zein Mersini Besharat; Luana Abballe; Alessandra Vacca; Francesca Iemma; Nevio Picci; Elisabetta Ferretti (168-174).
Display OmittedRedox-responsive nanoparticles were synthesized by desolvation of bovine serum albumin followed by disulfide-bond crosslinking with N, Nʹ-Bis (acryloyl) cystamine. Dynamic light scattering and transmission electron microscopy studies revealed spherical nanoparticles (mean diameter: 83 nm, polydispersity index: 0.3) that were glutathione-responsive. Confocal microscopy revealed rapid, efficient internalization of the nanoparticles by Daoy medulloblastoma cells and healthy controls (HaCaT keratinocytes). Cisplatin-loaded nanoparticles with drug:carrier ratios of 5%, 10%, and 20% were tested in both cell lines. The formulation with the highest drug:carrier ratio reduced Daoy and HaCaT cell viability with IC50 values of 6.19 and 11.17 μg mL−1, respectively. The differential cytotoxicity reflects the cancer cells’ higher glutathione content, which triggers more extensive disruption of the disulfide bond-mediated intra-particle cross-links, decreasing particle stability and increasing their cisplatin release. These findings support continuing efforts to improve the safety and efficacy of antineoplastic drug therapy for pediatric brain tumors using selective nanoparticle-based drug delivery systems.
Keywords: Albumin nanoparticles; Redox responsivity; Glutathione; Biocompatibility; Medulloblastoma; Cisplatin;

Ex vivo encapsulation of dexamethasone sodium phosphate into human autologous erythrocytes using fully automated biomedical equipment by Giovanni Mambrini; Marco Mandolini; Luigia Rossi; Francesca Pierigè; Giovanni Capogrossi; Patricia Salvati; Sonja Serafini; Luca Benatti; Mauro Magnani (175-184).
Display OmittedErythrocyte-based drug delivery systems are emerging as potential new solutions for the release of drugs into the bloodstream. The aim of the present work was to assess the performance of a fully automated process (EDS) for the ex-vivo encapsulation of the pro-drug dexamethasone sodium phosphate (DSP) into autologous erythrocytes in compliance with regulatory requirements. The loading method was based on reversible hypotonic hemolysis, which allows the opening of transient pores in the cell membrane to be crossed by DSP. The efficiency of encapsulation and the biochemical and physiological characteristics of the processed erythrocytes were investigated in blood samples from 34 healthy donors. It was found that the processed erythrocytes maintained their fundamental properties and the encapsulation process was reproducible. The EDS under study showed greater loading efficiency and reduced variability compared to previous EDS versions. Notably, these results were confirmed using blood samples from Ataxia Telangiectasia (AT) patients, 9.33 ± 1.40 and 19.41 ± 2.10 mg of DSP (mean ± SD, n = 134) by using 62.5 and 125 mg DSP loading quantities, respectively. These results support the use of the new EDS version 3.2.0 to investigate the effect of erythrocyte-delivered dexamethasone in regulatory trials in patients with AT.
Keywords: Carrier erythrocytes; Red cell loader; Glucocorticoids; Ataxia telangiectasia; Bioreactors;

Experimental observations and dissipative particle dynamic simulations on microstructures of pH-sensitive polymer containing amorphous solid dispersions by Mengchi Sun; Bingyu Li; Yanchun Li; Yangdan Liu; Qi Liu; Hailun Jiang; Zhonggui He; Yongshan Zhao; Jin Sun (185-195).
Display OmittedAmorphous solid dispersion (ASD) technique is an effective strategy to increase the dissolution rate of poorly soluble drugs. However, it is inherently unstable, and the molecular basis for achieving kinetic stability is not well understood. In this study, lacidipine-Eudragit_E_100 solid dispersions with 20% drug loading were prepared using the solvent evaporation. Dissolution tested showed that ASD had a significantly high rate, which was dependent on the pH of the medium. Based on time-dependent measurement of supersaturation and particle size, inhibition of crystal growth by Eudragit_E_100 differed at pH 1.2 and 6.8 to a great extent. Dissipative particle dynamic (DPD) simulation revealed that at pH 1.2, the swollen microstructures of the particles were associated with rapid drug release. At pH 6.8, a compacted microstructure of small amorphous particle-aggregated large particles was associated with slow dissolution. The DPD simulation provides insight into the structural basis for experimental observations, and thus is a useful tool to investigate the microstructures of ASD.
Keywords: Amorphous solid dispersion; Molecular basis; Microstructures; Dissipative particle dynamics;

Nasal drug delivery: Design of a novel mucoadhesive and in situ gelling polymer by Claudia Menzel; Max Jelkmann; Flavia Laffleur; Andreas Bernkop-Schnürch (196-202).
Display OmittedThe aim of the present study was to establish a novel polymeric excipient for liquid nasal dosage forms exhibiting viscosity increasing properties, improved mucoadhesion and stability towards oxidation in solution.In order to achieve this goal, 2-mercaptonicotinic acid was first coupled to l-cysteine by disulfide exchange reaction and after purification directly attached to the polymeric backbone of xanthan gum by carbodiimide mediated amide bond formation. The resulting conjugate was characterized with respect to the amount of coupled ligand, the in situ gelling behavior, mucoadhesive properties and stability towards oxidation. Furthermore, the influence of preactivated polymers on ciliary beat frequency (CBF) of porcine nasal epithelial cells was investigated.Results showed, that 252.52 ± 20.54 μmol of the ligand was attached per gram polymer. No free thiol groups could be detected on the polymeric backbone indicating entire preactivation. Rheological investigations of polymer mucus mixtures revealed a 1.7-fold and 2.5-fold enhanced mucoadhesion of entirely preactivated xanthan (Xan-Cys-MNA) compared to thiolated xanthan (Xan-Cys) and unmodified xanthan (Xan). Tensile force evaluation reported a 2.87 and 5.11-fold higher total work of adhesion (TWA) as well as a 1.63 and 2.41-fold higher maximum detachement force of Xan-Cys-MNA compared to Xan-Cys and Xan. In the presence of H2O2 as an oxidizing agent Xan-Cys-MNA showed unlike Xan-Cys no increase in viscosity, indicating high stability towards oxidation. Addition of CaCl2 to Xan-Cys-MNA solutions caused a decrease in viscosity at nevertheless higher total viscosity. Results from CBF studies proved nasal safety for the novel conjugate.According to these results, entirely preactivated thiolated xanthan gum seems to be a promising excipient for nasal dosage forms in order to improve drug bioavailability.
Keywords: Preactivated thiomers; Mucoadhesion; In situ gelling polymer; Liquid dosage form; Disulfide exchange; Oxidation; Nasal drug delivery;

Display OmittedSalt disproportionation (a conversion from the ionized to the neutral state) in solid formulations is a potential concern during manufacturing or storage of products containing a salt of the active pharmaceutical ingredient (API) due to the negative ramifications on product performance. However, it is challenging to find an effective approach to prevent or mitigate this undesirable reaction in formulations. Hence, the overall objective of this study is to explore novel formulation strategies to reduce the risk of salt disproportionation in pharmaceutical products. Crystals of pioglitazone hydrochloride salt were dispersed into polymeric matrices as a means of preventing the pharmaceutical salt from direct contact with problematic excipients. It was found that the level of salt disproportionation could be successfully reduced during storage or wet granulation by embedding a crystalline salt into a polymeric carrier. Furthermore, the impact of different polymers on the disproportionation process of a salt of a weakly basic API was investigated herein. Disproportionation of pioglitazone hydrochloride salt was found to be significantly affected by the physicochemical properties of different polymers including hygroscopicity and acidity of substituents. These findings provide an improved understanding of the role of polymeric carriers on the stability of a salt in solid formulations. Moreover, we also found that introducing acidifiers into granulation fluid can bring additional benefits to retard the disproportionation of pioglitazone HCl during the wet granulation process. These interesting discoveries offer new approaches to mitigate disproportionation of API salt during storage or processing, which allow pharmaceutical scientists to develop appropriate formulations with improved drug stability.
Keywords: Salt stability; Acid-base interaction; pH modifier; Hygroscopicity; Microenvironmental pH; Pioglitazone hydrochloride salt; Wet granulation;

Astaxanthin conjugated polypyrrole nanoparticles as a multimodal agent for photo-based therapy and imaging by Subramaniyan Bharathiraja; Panchanathan Manivasagan; Yun-Ok Oh; Madhappan Santha Moorthy; Hansu Seo; Nhat Quang Bui; Junghwan Oh (216-225).
Display OmittedPolymeric nanoparticles are emerging as promising candidates for photo-based therapy and imaging due to their versatile chemical properties and easy fabrication and functionalization. In the present study we synthesized polypyrrole nanoparticles by stabilization with astaxanthin conjugated bovine serum albumin polymer (PPy@BSA-Astx). The synthesized nanoparticles were biocompatible with MBA-MD-231 and HEK-293 cells. Interestingly, the fabricated nanoparticles produced reactive oxygen species under 808-nm laser exposure and exerted a hyperthermic effect when the power density of the laser was increased. The photodynamic efficiency of PPy@BSA-Astx was measured by DPBF assay, and it was found to generate sufficient amount of reactive radicals to kill the cells at a power density of 0.3 W/cm2. In photothermal aspect, the temperature level was reached to 57 °C within 5 min at 1 W/cm2 power density, at the concentration of 50 μg/mL. The in vitro cell toxicity studies showed concentration dependent photothermal and photodynamic toxicity. Fluorescence microscopic investigation explored the cell death and intra-cellular organ destruction by photodynamic treatment. In addition, we observed a strong photoacoustic signal from a tissue mimicking phantom study of nanoparticle treated MBA-MD-231 cells. In conclusion, the fabricated PPy@BSA-Astx nanoparticles can be used as photoacoustic imaging based prognostic agents for photothermal or photodynamic treatment.
Keywords: Albumin-polypyrrole; Astaxanthin; Photodynamic; Photothermal; Photoacoustic;

NaCl strongly modifies the physicochemical properties of aluminum hydroxide vaccine adjuvants by Jean-François Art; Aurélien vander Straeten; Christine C. Dupont-Gillain (226-233).
Display OmittedThe immunostimulation capacity of most vaccines is enhanced through antigen adsorption on aluminum hydroxide (AH) adjuvants. Varying the adsorption conditions, i.e. pH and ionic strength (I), changes the antigen adsorbed amount and therefore the ability of the vaccine to stimulate the immune system. Vaccine formulations are thus resulting from an empirical screening of the adsorption conditions. This work aims at studying the physicochemical effects of adjusting the ionic strength of commercial AH adjuvant particles suspensions with sodium chloride (NaCl). X-ray photoelectron spectroscopy data show that AH particles surface chemical composition is neither altered by I adjustment with NaCl nor by deposition on gold surfaces. The latter result provides the opportunity to use AH-coated gold surfaces as a platform for advanced surface analysis of adjuvant particles, e.g. by atomic force microscopy (AFM). The morphology of adjuvant particles recovered from native and NaCl-treated AH suspensions, as studied by scanning electron microscopy and AFM, reveals that AH particles aggregation state is significantly altered by NaCl addition. This is further confirmed by nitrogen adsorption experiments: I adjustment to 150 mM with NaCl strongly promotes AH particles aggregation leading to a strong decrease of the developed specific surface area. This work thus evidences the effect of NaCl on AH adjuvant structure, which may lead to alteration of formulated vaccines and to misinterpretation of data related to antigen adsorption on adjuvant particles.
Keywords: Vaccine formulation; Aluminum hydroxide adjuvant; Ionic strength; Sodium chloride; XPS; AFM; Specific surface area;

Structure–biocompatibility and transfection activity relationships of cationic polyaspartamides with (dialkylamino)alkyl and alkyl or hydroxyalkyl side groups by Diana Salakhieva; Vesta Shevchenko; Csaba Németh; Benjámin Gyarmati; András Szilágyi; Timur Abdullin (234-246).
Display OmittedA series of 14 cationic derivatives of poly(aspartic acid) i.e. cationic polyaspartamides with different (dialkylamino)alkyl and alkyl or hydroxyalkyl side groups was synthesized by nucleophilic addition on polysuccinimide. The resulting polyaspartamides have moderate amphiphilic properties. Relationships between the structure and ratio of side groups and in vitro properties of polyaspartamides, including their cytotoxic and membrane-damaging activity towards human cell lines, primary skin fibroblasts and erythrocytes, were established and discussed. Cationic polyaspartamides vary in their DNA-binding, condensing and nuclease-protecting characteristics depending on the concentration ratio of (dialkylamino)alkyl and alkyl or hydroxyalkyl side groups. Effective cell transfection was achieved upon polyaspartamide-mediated plasmid DNA delivery in serum-free medium in the presence of chloroquine. Effect of serum proteins adsorption onto polyaspartamide based polyplexes, and the role of concentration of polyplexes in culture medium in their colloidal stability and transfection process were demonstrated. Synthesized polyaspartamides are biocompatible and long-acting gene carriers, which are applied to cells after dilution and without washing, thus providing transfection level comparable to that of commercial transfection reagent.
Keywords: Poly(aspartic acid); Cationic polyaspartamides; Structure–activity relationship; Plasmid DNA delivery; Serum proteins; Dilution effect;

Acrylated chitosan for mucoadhesive drug delivery systems by Yulia Shitrit; Havazelet Bianco-Peled (247-255).
Display OmittedA new mucoadhesive polymer was synthesized by conjugating chitosan to poly(ethylene glycol)diacrylate (PEGDA) via the Michael type reaction. The product was characterized using NMR. Higher PEGDA grafting efficacy was observed with low molecular weight PEGDA (0.7 kDa), compared to long 10 kDa PEGDA. The acrylation percentage was calculated based on the reaction of ninhydrin with chitosan, and supported the qualitative NMR findings. The adhesive properties were studied by tensile test and rotating system involving detachment of polymer tablets from a fresh intestine sample. Chitosan modified with high molecular weight PEGDA presented improvement in mucoadhesive properties compared to both non-modified and thiolated chitosan. On the molecular level, rheology measurements of polymer/mucin mixtures provided additional evidence of strong interaction between modified chitosan and mucin glycoproteins. This new polymer shows promise as a useful polymeric carrier matrix for delivery systems, which could provide prolonged residence time of the vehicle on the mucosa surface.
Keywords: Chitosan; PEGDA (poly(ethylene glycol) diacrylate); Mucoadhesion;

Display OmittedThe aim of the present study is to enhance the skin penetration and deposition of 8-methoxypsoraln (8-MOP) via niosomal vesicles to increase its local efficacy and safety. 8-MOP niosomes were prepared by the thin film hydration method using Span 60 or Span 40 along with cholesterol at five different molar ratios. The obtained vesicles revealed high entrapment efficiencies (83.04–89.90%) with nanometric vesicle diameters (111.1–198.8 nm) of monodisperse distribution (PDI = 0.145–0.216), zeta potential values < −48.3 mV and spherical morphology under transmission electron microscopy. Optimized niosomal formulations depicted a biphasic in vitro release pattern in phosphate buffer (pH 5.5)/ethanol (7:3 v/v) and displayed good physical stability after storage for 6 months at room (20–25 °C) and refrigeration (4–8 °C) temperatures. The two optimized formulations were incorporated in 5% sodium carboxy methylcellulose based hydrogel matrix which showed optimum pH values (7.37–7.39), pseudoplastic with thixotropic rheological behavior and more retarded 8-MOP release, by 23.82 and 14.89%, compared to niosomal vesicles after 24 h. In vitro drug permeation and deposition studies, using rat skins, revealed promoted penetration and accumulation of 8-MOP after 8 h. The skin penetration was further confirmed in vivo by confocal laser scanning microscopy, after 2 h application period using rhodamine-loaded niosomal hydrogels compared to plain rhodamine hydrogel, as a florescence marker. Therefore, enhanced permeation and skin deposition of 8-MOP delivered by niosomes may help in improving the efficacy and safety of long-term treatment with 8-MOP.
Keywords: Niosomes; 8-methoxypsoralen; Topical delivery; Skin permeation; Hydrogel; Confocal laser scanning microscopy;

Targeted drug delivery of Sunitinib Malate to tumor blood vessels by cRGD-chiotosan-gold nanoparticles by Mohaddeseh Mahmoudi Saber; Sara Bahrainian; Rassoul Dinarvand; Fatemeh Atyabi (269-278).
Display OmittedThe unique characteristics of tumor vasculature represent an attractive strategy for targeted delivery of antitumor and antiangiogenic agents to the tumor. The purpose of this study was to prepare c(RGDfK) labeled chitosan capped gold nanoparticles [cRGD(CS-Au) NPs] as a carrier for selective intracellular delivery of Sunitinib Malate (STB) to the tumor vasculature. cRGD(CS-Au) NPs was formed by electrostatic interaction between cationic CS and anionic AuNPs. cRGD modified CS-Au NPs had a spherical shape with a narrow size distribution. The entrapment efficiency of sunitinib molecule was found to be 45.2% ± 2.05. Confocal microscopy showed enhanced and selective uptake of cRGD(CS-Au) NPs into MCF-7 and HUVEC cells compared with non-targeted CS-Au NPs. Our results suggest that it may be possible to use cRGD(CS-Au) NPs as a carrier for delivery of anticancer drugs, genes and biomolecules for inhibiting tumor vasculature.
Keywords: Angiogenesis; Gold nanoparticles; Chitosan; c(RGD); Sunitinib Malate;

About the impact of water movement on the permeation behaviour of nanoparticles in mucus by Angela Fabiano; Ylenia Zambito; Andreas Bernkop-Schnürch (279-285).
Display OmittedMethod to evaluate the diffusion of NP in mucus taking the intestinal water movement into account.The purpose of this study was to establish a method to evaluate the diffusion behaviour of nanoparticles (NP) in mucus taking also the water movement into account. For this purpose, NP based on different chitosan derivatives, either thiolated or not, and marked with fluorescein diacetate were prepared by ionotropic gelation with hyaluronan. NP size and polydispersity were in the respective intervals 363.5 ± 33.3–385.7 ± 36.5 nm, and 0.35 ± 0.11–0.39 ± 0.10. An in vitro study of water-assisted NP transport through mucus was realized by filling the barrel of a syringe kept in vertical position, tip down, with mucus. Then a bottom-to-surface PBS flow across the mucus layer was realized by connecting the tip of the syringe to the bottom of a vertical cylindrical vessel by a flexible tubing, filling the vessel with PBS, level with the surface of the mucus layer in the syringe, and dripping PBS into the vessel without causing any phase mixing. Although the mucoadhesive NP interact more strongly with the mucus, yet they are able to overcome this barrier with the aid of the water movement from lumen to epithelium. This new method promises to be more predictive of in vivo NP transport across the mucus than already reported methods, as it takes into account the water movement and regulates its contribution to the physiologic value.
Keywords: Intestinal water movement; Nanoparticles diffusion in mucus; Mucoadhesive nanoparticles; Thiolated chitosan; Intestinal absorption;

Engineered sodium hyaluronate respirable dry powders for pulmonary drug delivery by Francesco Martinelli; Anna Giulia Balducci; Abhinav Kumar; Fabio Sonvico; Ben Forbes; Ruggero Bettini; Francesca Buttini (286-295).
Display OmittedSodium hyaluronate (HYA) warrants attention as a material for inhalation due to its (i) therapeutic potential, (ii) utility as a formulation excipient or drug carrier, and (iii) ability to target lung inflammation and cancer. This study aimed to overcome formulation and manufacturing impediments to engineer biocompatible spray-dried HYA powders for inhalation.Novel methodology was developed to produce HYA microparticles by spray drying. Different types of surfactant were included in the formulation to improve powder respirability, which was evaluated in vitro using cascade impactors. The individual formulation components and formulated products were evaluated for their biocompatibility with A549 respiratory epithelial cells.The inclusion of stearyl surfactants, 5% w/v, produced the most respirable HYA-powders; FPF 59.0–66.3%. A trend to marginally higher respirability was observed for powders containing stearylamine > stearyl alcohol > cetostearyl alcohol. Pure HYA was biocompatible with A549 cells at all concentrations measured, but the biocompatibility of the stearyl surfactants (based on lethal concentration 50%; LC50) in the MTT assay ranked stearyl alcohol > cetostearyl alcohol > stearylamine with LC50 of 24.7, 13.2 and 1.8 μg/mL, respectively.We report the first respirable HYA powders produced by spray-drying. A lead formulation containing 5% stearyl alcohol was identified for further studies aimed at translating the proposed benefits of inhaled HYA into safe and clinically effective HYA products.
Keywords: Hyaluronic acid; Hyaluronan; Inhalation toxicology; Dry powder inhaler; Particle engineering;

Activity of vancomycin release from bioinspired coatings of hydroxyapatite or TiO2 nanotubes by Daniela Ionita; Daniela Bajenaru-Georgescu; Georgeta Totea; Anca Mazare; Patrik Schmuki; Ioana Demetrescu (296-302).
Display OmittedHerein we investigate the efficiency of various biomimetic coatings for localized drug delivery, using vancomycin as key therapeutic drug, which is a widely used antibiotic for the treatment of strong infections caused by positive Gram bacteria. We evaluate classical hydroxyapatite and biomimetic hydroxyapatite-collagen coatings obtained by electrochemical deposition as well as TiO2 nanotubes arrays obtained by electrochemical anodization. Surface morphology, compositional and structural data confirm the incorporation of vancomycin into the layers and drug release profiles for vancomycin evaluate their release ability. Namely, hydroxyapatite coatings lead to a ≈92% vancomycin release after 30 h and hydroxyapatite-collagen to 85%, while the TiO2 nanotubes layers lead to 78% release. The antibacterial effect of such drug loaded coatings is evaluated against S. aureus (Gram-positive bacteria). Our study shows that the vancomycin incorporated hydroxyapatite coatings lead to a faster release, while the nanotubular coatings may lead to longer time release and additionally both types of coatings ensure a good antibacterial inhibition.
Keywords: Hydroxyapatite; TiO2 nanotubes; Hydroxyapatite-collagen coatings; Vancomycin; S. aureus;

Effects of excipients and curing process on the abuse deterrent properties of directly compressed tablets by Ziyaur Rahman; Ahmed S. Zidan; Maxwell Korang-Yeboah; Yang Yang; Akhtar Siddiqui; Diaa Shakleya; Mansoor A. Khan; Celia Cruz; Muhammad Ashraf (303-311).
Display OmittedThe objective of the present investigation was to understand the effects of excipients and curing process on the abuse deterrent properties (ADP) of Polyox™ based directly compressible abuse deterrent tablet formulations (ADFs). The excipients investigated were lactose (monohydrate or anhydrous), microcrystalline cellulose and hydroxypropyl methylcellulose. The ADPs studied were tablet crush resistance or hardness, particle size distribution following mechanical manipulation, drug extraction in water and alcohol, syringeability and injectability. Other non-ADPs such as surface morphology and tablet dissolution were also studied. It was found that presence of 50% or more of water soluble or swellable excipient in the ADF tablets significantly affected the tablet hardness, particle size distribution following mechanical manipulation and drug extraction while small amount (5%) of excipients had either minimal or no effect on ADPs of these tablets. Addition of high molecular weight HPMC (K 100 M) affected syringeability and injectability of ADF. Curing process was found to affect ADPs (hardness, particle size distribution, drug extraction and syringeability and injectability) when compared with uncured tablet. In conclusion, addition of large amount of excipients, especially water soluble ones in Polyox™ based ADF tablets increase the risk of abuse by various routes of administration.
Keywords: Sotalol; Abuse deterrent tablet formulations; Abuse deterrent properties; Crush resistance; Syringeability and injectability;

Display OmittedPhosphodiesterase type 5 (PDE-5) inhibitors – among which sildenafil citrate (SC) – play a primary role in the treatment of pulmonary hypertension (PH). Yet, SC can be only administered orally or parenterally with lot of risks. Targeted delivery of SC to the lungs via inhalation/nebulization is mandatory. In this study, solid lipid nanoparticles (SLNs) loaded with SC were prepared and characterized in terms of colloidal, morphological and thermal properties. The amount of drug loaded and its release behavior were estimated as a function of formulation variables. The potential of lipid nanocarriers to retain their properties following nebulization and autoclaving was investigated. In addition, toxicity aspects of plain and loaded SLNs on A549 cells were studied with respect to concentration. Spherical SLNs in the size range (100–250 nm) were obtained. Particles ensured high encapsulation efficiency (88–100%) and sustained release of the payload over 24 h. Cell-based viability experiments revealed a concentration-dependant toxicity for both plain and loaded SLNs recording an IC50 of 516 and 384 μg/mL, respectively. Nebulization with jet nebulizer and sterilization via autoclaving affected neither the colloidal stability of SLNs nor the drug entrapment, proving their potential as pulmonary delivery system. Interaction of SLNs with mucin was a function of the emulsifier coating layer. Results yet seeking clinical evidence – might give promises of new therapy for PH of higher safety, better performance and higher patient compliance.
Keywords: Pulmonary hypertension; Phosphodiesterase-5-inhibitors; Sildenafil citrate; Solid lipid nanoparticles; Nebulization; Mucus interaction;

Crystallization of probucol from solution and the glassy state by Kohsaku Kawakami; Chie Ohba (322-328).
Display OmittedCrystallization of probucol (PBL) from both solution and glassy solid state was investigated. In the crystallization study from solution, six solvents and three methods, i.e., evaporation, addition of a poor solvent, and cooling on ice, were used to obtain various crystal forms. In addition to common two crystal forms (forms I and II), two further forms (forms III and cyclohexane-solvate) were found in this study, and their thermodynamic relationships were determined. Forms I and II are likely to be enantiotropically related with thermodynamic transition temperature below 5 °C. Isothermal crystallization studies revealed that PBL glass initially crystallized into form III between 25 and 50 °C, and then transformed to form I. The isothermal crystallization appears to be a powerful option to find uncommon crystal forms. The crystallization of PBL was identified to be pressure controlled, thus the physical stability of PBL glass is higher than that of typical compounds.
Keywords: Probucol; Polymorph; Crystallization;

Fabrication and characterisation of drug-loaded electrospun polymeric nanofibers for controlled release in hernia repair by Ivan J. Hall Barrientos; Eleonora Paladino; Sarah Brozio; Melissa K. Passarelli; Susan Moug; Richard A. Black; Clive G. Wilson; Dimitrios A. Lamprou (329-337).
Display OmittedThe chemical distribution and mechanical effects of drug compounds in loaded electrospun scaffolds, a potential material for hernia repair mesh, were characterised and the efficacy of the material was evaluated. Polycaprolactone electrospun fibres were loaded with either the antibacterial agent, irgasan, or the broad-spectrum antibiotic, levofloxacin. The samples were subsequently characterised by rheological studies, scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle goniometry (CAG), in vitro drug release studies, antibacterial studies and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Increased linear viscoelastic regions observed in the rheometry studies suggest that both irgasan and levofloxacin alter the internal structure of the native polymeric matrix. In vitro drug release studies from the loaded polymeric matrix showed significant differences in release rates for the two drug compounds under investigation. Irgasan showed sustained release, most likely driven by molecular diffusion through the scaffold. Conversely, levofloxacin exhibited a burst release profile indicative of phase separation at the edge of the fibres. Two scaffold types successfully inhibited bacterial growth when tested with strains of E. coli and S. aureus. Electrospinning drug-loaded polyester fibres is an alternative, feasible and effective method for fabricating non-woven fibrous meshes for controlled release in hernia repair.
Keywords: Electrospinning; Scaffolds; Hernia; Drug release; Physicochemical characterisation;

Display OmittedThe physico-chemical characterisation of nanoparticles is often lacking the determination of the glass transition temperature, a well-known parameter for the pure polymer carrier. In the present study the influence of water on the glass transition temperature of poly (DL-lactic-co-glycolic acid) nanoparticles was assessed. In addition, flurbiprofen and mTHPP as model drugs were incorporated in poly (DL-lactic-co-glycolic acid), poly (DL-lactic acid), and poly (L-lactic acid) nanoparticles. For flurbiprofen-loaded nanoparticles a decrease in the glass transition temperature was observed while mTHPP exerted no influence on this parameter.Based on this observation, the release behaviour of the drug-loaded nanoparticles was investigated at different temperatures. For all preparations an initial burst release was measured that could be attributed to the drug adsorbed to the large nanoparticle surface. At temperatures above the glass transition temperature an instant drug release of the nanoparticles was observed, while at lower temperatures less drug was released. It could be shown that the glass transition temperature of drug loaded nanoparticles in suspension more than the corresponding temperature of the pure polymer is the pivotal parameter when characterising a nanostructured drug delivery system.
Keywords: Drug delivery system; Poly (DL-lactic-co-glycolic acid); Poly (lactic acid); Differential scanning calorimetry; Release profile;

In-line monitoring of compaction properties on a rotary tablet press during tablet manufacturing of hot-melt extruded amorphous solid dispersions by W. Grymonpré; G. Verstraete; P.J. Van Bockstal; J. Van Renterghem; P. Rombouts; T. De Beer; J.P. Remon; C. Vervaet (348-358).
Display OmittedAs the number of applications for polymers in pharmaceutical development is increasing, there is need for fundamental understanding on how such compounds behave during tableting. This research is focussed on the tableting behaviour of amorphous polymers, their solid dispersions and the impact of hot-melt extrusion on the compaction properties of these materials. Soluplus, Kollidon VA 64 and Eudragit EPO were selected as amorphous polymers since these are widely studied carriers for solid dispersions, while Celecoxib was chosen as BCS class II model drug. Neat polymers and physical mixtures (up to 35% drug load) were processed by hot-melt extrusion (HME), milled and sieved to obtain powders with comparable particle sizes as the neat polymer. A novel approach was used for in-line analysis of the compaction properties on a rotary tablet press (Modul P, GEA) using complementary sensors and software (CDAAS, GEA). By combining ‘in-die’ and ‘out-of-die’ techniques, it was possible to investigate in a comprehensive way the impact of HME on the tableting behaviour of amorphous polymers and their formulations. The formation of stable glassy solutions altered the formulations towards more fragmentary behaviour under compression which was beneficial for the tabletability. Principal component analysis (PCA) was applied to summarize the behaviour during compaction of the formulations, enabling the selection of Soluplus and Kollidon VA 64 as the most favourable polymers for compaction of glassy solutions.
Keywords: Amorphous polymers; Hot-melt extrusion; Powder compaction; In-line monitoring; Rotary tablet press; Multivariate data analysis;

Platinum pharmacokinetics in mice following inhalation of cisplatin dry powders with different release and lung retention properties by Vincent Levet; Romain Merlos; Rémi Rosière; Karim Amighi; Nathalie Wauthoz (359-372).
Pharmacokinetics of cisplatin administered by the pulmonary route were established in mice using dry powders inhaler (DPI) formulations showing immediate (F1) and controlled release (CR, solid lipid microparticles) in vitro, without (F2) or with PEGylated excipients (F3, F4). Formulation administration was realized using dry powder blends (correspondingly named thereafter F1B to F4B) able to reproducibly deliver particles in vivo using a DP-4M Dry Powder Insufflator™. Their platinum pharmacokinetics were established over 48 h in lungs, total blood and non-target organs vs. IV and endotracheal nebulization (EN). EN and F1B were rapidly distributed from the lungs (t 1/2 i 2.6 and 5.0 min). F2B was eliminated in ∼1 h (t 1/2 i 9.0 min). F3B lung retention was sustained for ∼7 h (t 1/2 i 59.9 min), increasing lung AUC 11-, 4- and 3-fold vs. IV, F1B and F2B. Total blood t max were higher and AUC and C max lower using the pulmonary route vs. IV. Kidney C max was reduced 6-, 2- and 3-fold for F1B, F2B and F3B. AUC in kidneys were 2- to 3-fold lower for F1B and F2B vs. IV but comparable for IV vs. F3B, probably because of kidney saturation. PEGylated solid lipid microparticles provided cisplatin particles with interesting lung retention and CR properties.Display Omitted
Keywords: Dry powder for inhalation; Lung retention; Lung cancer chemotherapy; Controlled release; Stealth formulation; Solid lipid microparticles; Cisplatin;

Sensitivity analysis of a pharmaceutical tablet production process from the control engineering perspective by Jakob Rehrl; Arlin Gruber; Johannes G. Khinast; Martin Horn (373-382).
Display OmittedThis paper presents a sensitivity analysis of a pharmaceutical direct compaction process. Sensitivity analysis is an important tool for gaining valuable process insights and designing a process control concept. Examining its results in a systematic manner makes it possible to assign actuating signals to controlled variables. This paper presents mathematical models for individual unit operations, on which the sensitivity analysis is based. Two sensitivity analysis methods are outlined: (i) based on the so-called Sobol indices and (ii) based on the steady-state gains and the frequency response of the proposed plant model.
Keywords: Sensitivity analysis; Pharmaceutical manufacturing; Dynamic systems; Process modeling;

Enhanced neuroprotection with decellularized brain extracellular matrix containing bFGF after intracerebral transplantation in Parkinson’s disease rat model by Qian Lin; Ho Lun Wong; Fu-Rong Tian; Ya-Dong Huang; Jie Xu; Jing-Jing Yang; Pian-Pian Chen; Zi-Liang Fan; Cui-Tao Lu; Ying-Zheng Zhao (383-394).
Display OmittedExtracellular matrix-based biomaterials have many advantages over synthetic polymer materials for regenerative medicine applications. In central nervous system (CNS), basic fibroblast growth factor (bFGF) is widely studied as a potential agent for Parkinson’s disease (PD). However, the poor stability of bFGF hampered its clinical use. In this study, CNS-derived biologic scaffold containing bFGF was used to enhance and extend the neuroprotective effect of bFGF on PD targeted therapy. Decellularized brain extracellular matrix (dcBECM) was prepared by chemical extraction. The biocompatibility of dcBECM was evaluated using CCK-8 assay and magnetic resonance imaging (MRI). The controlled-release behavior of dcBECM containing bFGF (bFGF + dcBECM) was confirmed by ELISA assay. Furthermore, the cytocompatibility and neuroprotective effect of bFGF + dcBECM was evaluated in vitro and in vivo. From results, dcBECM showed a three-dimensional network structure with high biocompatibility. MRI of dcBECM implanted rats showed nearly seamless fusion of dcBECM with the adjoining tissues. The cumulative release rate of bFGF + dcBECM in vitro reached to 75.88% at 10 h and maintained sustained release trend during the observation. ELISA results in vivo further confirmed the sustained-release behavior (from 12 h to 3d) of bFGF + dcBECM in brain tissues. Among the experimental groups, bFGF + dcBECM group showed the highest cell survival rate of PD model cells, improved behavioral recovery and positive expressions of neurotrophic proteins in PD recovered rats. In conclusion, sustained neuroprotection in PD rats was achieved by using bFGF + dcBECM. The combination of dcBECM and bFGF would be a promising therapeutic strategy to realize an effective and safe alternative for CNS disease treatment.
Keywords: Decellularized brain extracellular matrix; Basic fibroblast growth factor; Parkinson’s disease; Neuroprotection; Transplantation;

Biopolymeric self-assembled nanoparticles for enhanced antibacterial activity of Ag-based compounds by Dhanya Dhanyalayam; Luca Scrivano; Ortensia Ilaria Parisi; Maria Stefania Sinicropi; Antonietta Fazio; Carmela Saturnino; Maria Rosaria Plutino; Francesca Di Cristo; Francesco Puoci; Anna Rita Cappello; Pasquale Longo (395-402).
Display OmittedMicrobial infections still remain one of the main issues for human health. The rapid development of resistance towards the most common antimicrobial drugs in bacteria represents today a challenge in the infections management. In the present work we have investigated the antibacterial activity of a group of compounds, namely silver N-heterocyclic carbene complexes, against a broad spectrum of bacteria. For the most promising compound, a biopolymeric nanocarrier has been developed, in order to potentiate the metal complex activity against both Gram +ve and Gram −ve. The polymeric nanovehicle is based on dextran, modified with oleic acid residues, that confer amphiphilic properties to the polysaccharide. We have characterized the obtained biomaterial and studied its ability to self-assemble into nanoparticles in aqueous environment. Next, the transdermal diffusion analyses have been carried out to evaluate the ability of the polymeric particles to penetrate tissues. Thanks to the strategy adopted, we have fabricated an antibacterial system to which K. pneumoniae and E. coli are the most sensitive.
Keywords: Dextran; Hydrophilic-hydrophobic polymer; Oleic acid; Antibacterial drug; Polymer nanovesicles; Silver; N-heterocyclic carbene;

Microphase separation in solid lipid dosage forms as the cause of drug release instability by Diogo Gomes Lopes; Ioannis Koutsamanis; Karin Becker; Otto Scheibelhofer; Peter Laggner; Detlev Haack; Michael Stehr; Andreas Zimmer; Sharareh Salar-Behzadi (403-412).
Display OmittedAlthough lipid excipients are of increasing interest for development of taste-masked and modified release formulations, the drug release instability and the lack of mechanistic understanding in that regard still prevent their larger-scale application. In this work, we investigated the physical stability of a binary (tripalmitin/polysorbate 65) lipid coating formulation with a known stable polymorphism. The coating composition was characterized using DSC to construct the phase diagram of binary system and polarized light microscopy to display the microstructure organization. The water uptake and the erosion of slabs cast from the coating formulations were investigated post-production and after storage. Subsequently, N-acetylcysteine particles were coated with the selected formulations and the drug release stability was investigated. Additionally, microstructure characterization was performed via SEM and X-ray diffraction. The drug release instability was explained by polysorbate 65 and tripalmitin phase growth during storage, especially at 40 °C, suggesting that polysorbate 65 can leak out of tripalmitin spherulitic structures, creating lipophilic and impermeable tripalmitin regions. The growth of polysorbate 65 phase leads to larger hydrophilic channels with reduced tortuosity. This work indicates that for obtaining stable drug release profiles from advanced lipid formulations, microphase separation should be prevented during storage.
Keywords: Solid lipid excipients; Drug release stability; Hot-melt coating; Polymorphism; Microphase separation;

Quality by Design (QbD)-enabled development of aceclofenac loaded-nano structured lipid carriers (NLCs): An improved dermatokinetic profile for inflammatory disorder(s) by Neeraj K. Garg; Gajanand Sharma; Bhupinder Singh; Pradip Nirbhavane; Rajeev K. Tyagi; Rahul Shukla; O.P. Katare (413-431).
Display OmittedPresent study was designed to prepare and characterize aceclofenac loaded nanostructured lipid carriers (NLCs) employing Quality by Design (QbD)-oriented approach. The NLCs were evaluated for their transdermal penetration potential and stability. Aceclofenac loaded nanostructured lipid carriers (NLCs) were prepared & characterized, by employing Quality by Design (QbD)-oriented approach and further evaluated for transdermal penetration potential and stability. Different lipids and surfactants were chosen to prepare NLCs using microemulsion method as critical material attributes (CMAs). A 33 factorial design was used for optimization of NLCs, and evaluating them for different critical quality attributes (CQAs), viz. particle size, polydispersity index (PDI), zeta potential, in vitro drug release, entrapment efficiency. The effect of CMAs such as lipids, oil: lipid ratio and concentration of surfactants on CQAs viz. drug entrapment efficiency and particle size were systematically evaluated to optimize NLCs. The optimized NLCs were further incorporated into carbopol gel and characterized for texture and rheology profile followed by in vitro and in vivo evaluations. The optimized ACE-NLCs were found to be spherical, nanometric in size with higher drug loading and entrapment efficiency. Results of the in vitro drug release study showed that the developed formulation followed Korsmeyer-Peppas model showing Fickian diffusion. The release was biphasic i.e., initial burst release followed by sustained drug release upto 48 h. The optimized NLCs-based gel formulation showed superior texture, rheological profile and showed better cell uptake efficiency on hyperkeratinocytic cells (HaCaT cell lines) with higher ex vivo skin permeability efficiency vis-à-vis marketed formulation. In conclusion, dermatokinetic modeling and pharmacodynamic study using carrageenan induced edema mice suggests that aceclofenac loaded NLCs hydrogel may provide a better delivery alternative to target various skin layers.
Keywords: Aceclofenac; Nanostructured lipid carriers (NLCs); Quality by Design (QbD); Optimization;