International Journal of Pharmaceutics (v.525, #1)

Solubilisation of the poorly-water soluble drug, testosterone propionate, in co-surfactant-free, dilutable, oil-in-water microemulsions stabilized by zwitterionic surfactants of varying alkyl chain length, namely 3-(N,N-dimethyloctylammonio)propanesulfonate and 3-(N,N-dimethyldodecylammonio)propanesulfonate and containing one of four ethyl ester oils, has been investigated. Both 3-(N,N-dimethyloctylammonio)propanesulfonate and 3-(N,N-dimethyldodecylammonio)propanesulfonate-stabilized microemulsions containing two short chain length oils, ethyl butyrate and ethyl caprylate, while only 3-(N,N-dimethyldodecylammonio)propanesulfonate formed microemulsions incorporating the longer chain length oils, ethyl palmitate and ethyl oleate, albeit to a very much reduced extent. Significantly the microemulsions containing the short chain length oils, ethyl butyrate and ethyl caprylate solubilised more testosterone propionate than the corresponding micelles. However, an inverse correlation existed between testosterone propionate solubility in the bulk oil and solubilisation in the microemulsions, in that ethyl caprylate containing microemulsions solubilised more testosterone propionate than those containing an equivalent amount of ethyl butyrate, despite the drug being more soluble in ethyl butyrate. These results suggest that drug solubility in bulk oil is a poor indicator of drug solubility in microemulsions containing that oil, and whether or not the addition of oil improves drug solubility is dependent upon on how it is incorporated within the microemulsion. The longer the chain length of the oil, the more likely the oil is to form a core in the microemulsion droplet, resulting in an additional locus of drug solubilisation and the possibility of an enhanced solubilisation capacity.
Keywords: 3-(N,N-dimethylalkylammonio)propanesulfonate; Oil-in-water microemulsions; TP; Ethyl ester oils;

Preparation and investigation of controlled-release glipizide novel oral device with three-dimensional printing by Qijun Li; Haoyang Wen; Danyang Jia; Xiaoying Guan; Hao Pan; Yue Yang; Shihui Yu; Zhihong Zhu; Rongwu Xiang; Weisan Pan (5-11).
Display OmittedThe purpose of this study was to explore the feasibility of combining fused deposition modeling (FDM) 3D printing technology with hot melt extrusion (HME) to fabricate a novel controlled-release drug delivery device. Glipizide used in the treatment of diabetes was selected as model drug, and was successfully loaded into commercial polyvinyl alcohol (PVA) filaments by HME method. The drug-loaded filaments were printed through a dual-nozzle 3D printer, and finally formed a double-chamber device composed by a tablet embedded within a larger tablet (DuoTablet), each chamber contains different contents of glipizide. The drug-loaded 3D printed device was evaluated for drug release under in vitro dissolution condition, and we found the release profile fit Korsmeyer–Peppas release kinetics. With the double-chamber design, it is feasible to design either controlled drug release or delayed drug release behavior by reasonably arranging the concentration distribution of the drug in the device. The characteristics of the external layer performed main influence on the release profile of the internal compartment such as lag-time or rate of release. The results of this study suggest the potential of 3D printing to fabricate controlled-release drug delivery system containing multiple drug concentration distributions via hot melt extrusion method and specialized design configurations.
Keywords: Three dimensional printing; Controlled-release; Hot melt extrusion; PVA; Multiple drug concentration distributions; Double-chamber design;

Targeted drug delivery system to neural cells utilizes the nicotinic acetylcholine receptor by Rachel Huey; Barry O’Hagan; Paul McCarron; Susan Hawthorne (12-20).
Display OmittedDrug delivery to the brain is still a major challenge in the field of therapeutics, especially for large and hydrophilic compounds. In order to achieve drug delivery of therapeutic concentration in the central nervous system, the problematic blood brain barrier (BBB) must be overcome. This work presents the formulation of a targeted nanoparticle-based drug delivery system using a specific neural cell targeting ligand, rabies virus derived peptide (RDP). Characterization studies revealed that RDP could be conjugated to drug-loaded PLGA nanoparticles of average diameter 257.10 ± 22.39 nm and zeta potential of −5.51 ± 0.73 mV. In vitro studies showed that addition of RDP to nanoparticles enhanced drug accumulation in a neural cell line specifically as opposed to non-neural cell lines. It was revealed that this drug delivery system is reliant upon nicotinic acetylcholine receptor (nAChR) function for RDP-facilitated effects, supporting a cellular uptake mechanism of action. The specific neural cell targeting capabilities of RDP via the nAChR offers a non-toxic, non-invasive and promising approach to the delivery of therapeutics to the brain.
Keywords: Drug delivery system; Rabies virus; Targeted nanoparticles; Neural; Blood brain barrier (BBB); Nicotinic acetylcholine receptor;

PEGylated doxorubicin nanoparticles mediated by HN-1 peptide for targeted treatment of oral squamous cell carcinoma by Yue Wang; Guoyun Wan; Zhiyuan Li; Shurui Shi; Bowei Chen; Chunyu Li; Lianyun Zhang; Yinsong Wang (21-31).
Display OmittedHN-1, a 12-amino acid peptide, has been reported to possess strong capabilities for targeting and penetrating head and neck squamous cell carcinoma. Here, we designed a simple but effective nanoparticle system for the delivery of doxorubicin (DOX) targeting oral squamous cell carcinoma (OSCC) through the mediation of HN-1. PEGylated DOX (PD) was firstly synthesized by the conjugation of DOX with bis-amino-terminated poly(ethylene glycol) via succinyl linkage, and then PD nanoparticles were prepared by a modified nanoprecipitation method. After that, PD nanoparticles were surface-modified with HN-1 to form HNPD nanoparticles, which had a uniform spherical shape and a small size about 150 nm. In human OSCC cells (CAL-27 and SCC-25), HNPD nanoparticles exhibited significantly higher cellular uptakes and cytotoxicities than PD nanoparticles. Furthermore, HNPD nanoparticles showed a certain degree of functional selectivity for CAL-27 and SCC-25 cells as compared to human hepatoma HepG2 cells. In SCC-25 tumor-bearing nude mice, HNPD nanoparticles showed remarkably enhanced tumor-targeting and penetrating efficiencies as compared to PD nanoparticles, and effectively inhibited the tumor growth. In conclusion, our study demonstrated for the first time that HN-1 could be used for mediating the OSCC-targeted delivery of nanoparticles.
Keywords: HN-1; Oral squamous cell carcinoma; Nanoparticle; Targeted treatment; Doxorubicin;

Enhancement of dissolution rate through eutectic mixture and solid solution of posaconazole and benznidazole by Camila Bezerra Melo Figueirêdo; Daniela Nadvorny; Amanda Carla Quintas de Medeiros Vieira; José Lamartine Soares Sobrinho; Pedro José Rolim Neto; Ping I. Lee; Monica Felts de La Roca Soares (32-42).
Display OmittedBenznidazole (BNZ), the only commercialized antichagasic drug, and the antifungal compound posaconazole (PCZ) have shown synergistic action in the therapy of Chagas disease, however both active pharmaceutical ingredients (APIs) exhibit low aqueous solubility potentially limiting their bioavailability and therapeutic efficacy. In this paper, we report for the first time the formation of a eutectic mixture as well as an amorphous solid solution of PCZ and BNZ (at the same characteristic ratio of 80:20 wt%), which provided enhanced solubility and dissolution rate for both APIs. This eutectic system was characterized by DSC and the melting points obtained were used for the construction of a phase diagram. The preservation of the characteristic PXRD patterns and the IR spectra of the parent APIs, and the visualization of a characteristic eutectic lamellar crystalline microstructure using Confocal Raman Microscopy confirm this system as a true eutectic mixture. The PXRD result also confirms the amorphous nature of the prepared solid solution. Theoretical chemical analyses indicate the predominance of π-stacking interactions in the amorphous solid solution, whereas an electrostatic interaction between the APIs is responsible for maintaining the alternating lamellar crystalline microstructure in the eutectic mixture. Both the eutectic mixture and the amorphous solid solution happen to have a characteristic PCZ to BNZ ratio similar to that of their pharmacological doses for treating Chagas disease, thus providing a unique therapeutic combination dose with enhanced apparent solubility and dissolution rate.
Keywords: Trypanosoma cruzi; Chagas disease; Eutectic system; Amorphous solid solution; Apparent solubility;

Display OmittedThe aim was to investigate intracorneal iontophoresis of biolabile triamcinolone acetonide (TA) amino acid ester prodrugs (TA-AA). Arginine and lysine esters of TA (TA-Arg and TA-Lys, respectively) were synthesized and characterized; quantification was performed by HPLC-UV and UHPLC–MS/MS. The aqueous solubility of the prodrugs (at pH 5.5) was ∼1000-fold greater than TA. Anodal iontophoresis (10 min at 3 mA/cm2) of TA-AA was investigated using isolated porcine cornea. Although no statistically significant difference was observed in total intracorneal delivery of TA (468.25 ± 59.70 and 540.85 ± 79.16 nmolTA/cm2, for TA-Arg and TA-Lys, respectively), the different susceptibilities of the prodrugs to hydrolysis influenced intracorneal biodistribution. Quantification of TA in twenty-five 40 μm thick corneal lamellae revealed significantly deeper penetration of TA following TA-Lys iontophoresis. Its superior resistance to hydrolysis enabled sustained electromigration into the deeper cornea suggesting judicious prodrug selection might enable targeted regioselective drug delivery. The intracorneal biodistribution following anodal iontophoresis of TA-Arg (2.3 mM; 10 min, 3 mA/cm2) was visualized by full field optical coherence tomography providing qualitative confirmation of the extensive intracorneal penetration of TA. Short duration iontophoresis of TA-AA prodrugs may improve deep corneal bioavailability and efficacy in vivo, constituting a “single-shot” treatment option for corneal allograft rejection.
Keywords: Corneal graft rejection; Triamcinolone acetonide; Prodrug; Iontophoresis; Intracorneal biodistribution; Full field optical coherence tomography;

Pressure-temperature phase diagram of the dimorphism of the anti-inflammatory drug nimesulide by M. Barrio; J. Huguet; B. Robert; I.B. Rietveld; R. Céolin; J.Ll. Tamarit (54-59).
Display OmittedUnderstanding the phase behavior of active pharmaceutical ingredients is important for formulations of dosage forms and regulatory reasons. Nimesulide is an anti-inflammatory drug that is known to exhibit dimorphism; however up to now its stability behavior was not clear, as few thermodynamic data were available. Therefore, calorimetric melting data have been obtained, which were found to be T I-L  = 422.4 ± 1.0 K, ΔI → L H  = 117.5 ± 5.2 J g−1,  T II-L  = 419.8 ± 1.0 K and ΔII → L H  = 108.6 ± 3.3 J g−1. In addition, vapor-pressure data, high-pressure melting data, and specific volumes have been obtained. It is demonstrated that form II is intrinsically monotropic in relation to form I and the latter would thus be the best polymorph to use for drug formulations. This result has been obtained by experimental means, involving high-pressure measurements. Furthermore, it has been shown that with very limited experimental and statistical data, the same conclusion can be obtained, demonstrating that in first instance topological pressure-temperature phase diagrams can be obtained without necessarily measuring any high-pressure data. It provides a quick method to verify the phase behavior of the known phases of an active pharmaceutical ingredient under different pressure and temperature conditions.
Keywords: Polymorphism; Thermodynamics; Pressure-temperature phase diagram; Phase behavior; Crystallography; Calorimetry; Preformulation;

Novel dabigatran etexilate hemisuccinate-loaded polycap: Physicochemical characterisation and in vivo evaluation in beagle dogs by Jung Hyun Cho; Jin Cheul Kim; Hyung-Seo Kim; Dong Shik Kim; Kyeong Soo Kim; Yong Il Kim; Chul Soon Yong; Jong Oh Kim; Yu Seok Youn; Kyung Taek Oh; Jong Soo Woo; Han-Gon Choi (60-70).
Display OmittedThe purpose of this study was to develop a novel dabigatran etexilate hemisuccinate (DEH) salt-loaded polycap with bioequivalence to the dabigatran etexilate mesylate (DEM)-loaded commercial product. DEH prepared with dabigatran etexilate base (DE) and succinic acid was less hygroscopic but less soluble than DEM. Numerous micronized DEHs and DEH-loaded solid dispersions were prepared employing the spiral jet-milling and spray-drying techniques, respectively. Among the formulations prepared, a micronized DEH prepared with the injection air at 1.5 bar and the grinding air at 2 bar, and a DEH-loaded solid dispersion prepared with 6 g HPMC most improved the drug solubility, respectively. Moreover, the micronized DEH provided more increased drug solubility and dissolution compared with the solid dispersion, even though its drug solubility was still lower than that of DEM. Unlike the situation in other studies, the enhanced solubility and dissolution of DEH was more due to particle size reduction than to a change to the amorphous form. The micronized DEH prepared with Myrj 52S had greater drug solubility than preparations with other surfactants. Among the organic acids investigated, only fumaric acid (128.8 mg) showed a similar pattern in pH changes to the DEM-loaded commercial product. Furthermore, in order to make the environment acidic while preventing the direct contact of the drug with fumaric acid, the polycap was composed of a tablet containing the micronized DEH, Myrj 52S and other ingredients, and separate fumaric acid. This micronized DEH-loaded polycap was dissolution- and bio-equivalent to the DEM-loaded commercial product in beagle dogs. Thus, the novel micronized DEH-loaded polycap would be a promising alternative to the DEM-loaded commercial product.
Keywords: Dabigatran etexilate; Dabigatran etexilate hemisuccinate; Jet milling; Pulverisation; Solubility; Bioequivalence;

Schematic representation for the conjugation of Imipenem and Meropenem with citrate-capped gold nanoparticles.Display OmittedDespite the fact that carbapenems (powerful β-lactams antibiotics) were able to fight serious infectious diseases, nowadays the spread of carbapenems-resistant bacteria is considered the main challenge in antibacterial therapy. In this study, we focused on evaluating the surface conjugation of carbapenems (imipenem and meropenem) with gold nanoparticles as a delivering strategy to specifically and safely maximize their therapeutic efficacy while destroying the developing resistance of the pathogens. Different particle size formulae (35, 70 and 200 nm) were prepared by citrate reduction method. The prepared nanoparticles were functionalized with imipenem (Ipm) or meropenem (Mem) and physico-chemically characterized for loading efficiency, particle size, morphology, and in-vitro release. The antibacterial efficacy was also evaluated against carbapenems resistant Gram-negative bacteria isolated from infected human, through measuring the minimum inhibitory concentration and antibiotic kill test. All the obtained gold nanoparticles showed a distinct nano-size with loading efficiency up to 72% and 74% for Ipm and Mem, respectively. The conjugation and physico-chemical stability of the formulated carbapenems were confirmed by FTIR and X-RPD. Diffusion driven release behavior was observed for both Ipm and Mem from all of the loaded gold nanoparticles. For both Ipm and Mem, formula with 35 nm diameter showed the most significant enhancement in antibacterial activity against all the selected isolates including Klebsiella pneumoniae, Proteus mirabilis and Acinteobacter baumanii. Ipm loaded Gold nanoparticles demonstrated decrease in the MIC of Ipm down to four folds, whereas, Mem loaded gold nanoparticles showed decrease in the MIC of Mem down to three folds on the tested bacterial isolates. Based on these results, the formulation of carbapenems-loaded gold nanoparticles demonstrated to be a promising nano-size delivery vehicle for improving the therapeutic activity and destroying the bacterial resistance for carbapenems.
Keywords: Gold nanoparticles; Imipenem; Meropenem; Antibacterial delivery; Bacterial resistance;

Optics-based compressibility parameter for pharmaceutical tablets obtained with the aid of the terahertz refractive index by Mousumi Chakraborty; Cathy Ridgway; Prince Bawuah; Daniel Markl; Patrick A.C. Gane; Jarkko Ketolainen; J. Axel Zeitler; Kai-Erik Peiponen (85-91).
Display OmittedThe objective of this study is to propose a novel optical compressibility parameter for porous pharmaceutical tablets. This parameter is defined with the aid of the effective refractive index of a tablet that is obtained from non-destructive and contactless terahertz (THz) time-delay transmission measurement. The optical compressibility parameter of two training sets of pharmaceutical tablets with a priori known porosity and mass fraction of a drug was investigated. Both pharmaceutical sets were compressed with one of the most commonly used excipients, namely microcrystalline cellulose (MCC) and drug Indomethacin. The optical compressibility clearly correlates with the skeletal bulk modulus determined by mercury porosimetry and the recently proposed terahertz lumped structural parameter calculated from terahertz measurements. This lumped structural parameter can be used to analyse the pattern of arrangement of excipient and drug particles in porous pharmaceutical tablets. Therefore, we propose that the optical compressibility can serve as a quality parameter of a pharmaceutical tablet corresponding with the skeletal bulk modulus of the porous tablet, which is related to structural arrangement of the powder particles in the tablet.
Keywords: Pharmaceutical tablet; Microcrystalline cellulose; Indomethacin; Optical compressibility; Structural parameter; Skeletal bulk modulus; Terahertz;

Enhanced anti-rheumatic activity of methotrexate-entrapped ultradeformable liposomal gel in adjuvant-induced arthritis rat model by Alam Zeb; Omer Salman Qureshi; Chan-Hee Yu; Muhammad Akram; Hyung-Seo Kim; Myung-Sic Kim; Jong-Ho Kang; Arshad Majid; Sun-Young Chang; Ok-Nam Bae; Jin-Ki Kim (92-100).
Display OmittedThe aim of this study is to investigate in vivo anti-rheumatic activity of methotrexate-entrapped ultradeformable liposomal gel (MTX-UDLs-gel) in adjuvant-induced arthritis rat model. Methotrexate-entrapped ultradeformable liposomes (MTX-UDLs) with the optimal phosphatidylcholine to Tween 80 ratio (7:3, w/w) were incorporated into 1% Carbopol gel. MTX-UDLs-gel was characterized in terms of appearance, clarity, homogeneity, pH and drug content. The permeation of MTX-UDLs-gel across rat skin was investigated using Franz diffusion cell. In vivo anti-rheumatic activity of MTX-UDLs-gel was assessed in terms of edema volume, paw edema and leukocyte infiltration scores, histopathological analysis and inflammatory cytokines level in complete Freund’s adjuvant (CFA)-induced arthritis rat model. MTX-UDLs-gel showed good homogeneity and clarity, neutral pH and about 99.5% drug content. The cumulative amount of MTX permeated for 24 h from MTX-UDLs-gel (164.6 μg) was 1.5 and 2.15 times higher than that of MTX-CLs-gel (113.3 μg) and MTX-plain-gel (76.6 μg), respectively. MTX-UDLs-gel significantly alleviated the severity of inflammation by reducing edema volume, histological scores and accumulation of neutrophils and improving tissue architecture in CFA-induced arthritis rat model. MTX-UDLs-gel effectively suppressed the expression of pro-inflammatory cytokines, TNF-α and IL-1β, in paw tissues. In conclusion, the developed MTX-UDLs-gel has a great potential for effective delivery of MTX into the inflamed joints in rheumatoid arthritis.
Keywords: Methotrexate; Ultradeformable liposomes; Rheumatoid arthritis; Transdermal delivery; Complete Freund’s adjuvant; Inflammation;

Display OmittedDevelopments in the field of molecular oncology have revealed that resistance to chemotherapeutics is acqured through several mechanisms including overexpression of common oncogenic proteins. Signal Transducer and Activator of Transcription 3 (STAT3) is one of these oncogenes that is overexpressed in many cancer types. RNA interference (RNAi) is proven powerful tool for downregulating STAT3, allowing re-sensitization of resistant cancer cells. However, delivery of RNA interference-mediating molecules for STAT3 downregulation in lung cancer cells is limited to a small number of studies most of which employ commercially available transfection kits. The aim of this study was to develop and evaluate cationic solid lipid nanoparticles for delivery of RNAi-mediating plasmid DNA in order to down regulate STAT3 in cisplatin resistant lung cancer cells. We focused on obtaining cSLN:plasmid DNA complexes with size below or equal to 100 nm, and a positive zeta potential. Two successful candidate cSLN:plasmid DNA complexes (K2 and K3) were selected for in vitro tests and cell culture studies. These formulations have particle sizes of 98 and 93 nm, and zeta potential values of 10.5 and 8.9 mV, respectively. Plasmid DNA in these complexes was protected against DNaseI and serum-mediated degradation. Substantial part of DNA retained its supercoiled and circular conformation. TEM images showed nearly spherical complex structure. Both formulations reduced STAT3 expression by approx. 5-fold in cisplatin resistant Calu1 cell line and increased the sensitivity of cells to cisplatin.
Keywords: STAT3 downregulation; Lung cancer; Chemotherapy resistance reversal; Plasmid delivery; Hot microemulsion method; SLNs;

Laser-treated electrospun fibers loaded with nano-hydroxyapatite for bone tissue engineering by Javier Aragon; Nuria Navascues; Gracia Mendoza; Silvia Irusta (112-122).
Display OmittedCore-shell polycaprolactone/polycaprolactone (PCL/PCL) and polycaprolactone/polyvinyl acetate (PCL/PVAc) electrospun fibers loaded with synthesized nanohydroxyapatite (HAn) were lased treated to create microporosity. The prepared materials were characterized by XRD, FTIR, TEM and SEM. Uniform and randomly oriented beadless fibrous structures were obtained in all cases. Fibers diameters were in the 150–300 nm range. Needle-like HAn nanoparticles with mean diameters of 20 nm and length of approximately 150 nm were mostly encase inside the fibers. Laser treated materials present micropores with diameters in the range 70–120 μm for PCL-HAn/PCL fibers and in the 50–90 μm range for PCL-HAn/PVAC material. Only samples containing HAn presented bioactivity after incubation during 30 days in simulated body fluid. All scaffolds presented high viability, very low mortality, and human osteoblast proliferation. Biocompatibility was increased by laser treatment due to the surface and porosity modification.
Keywords: Bone regeneration; Scaffold; Laser treatment; Electrospinning; Nanohydroxyapatite;

A novel serum-stable liver targeted cytotoxic system using valerate-conjugated chitosan nanoparticles surface decorated with glycyrrhizin by Eman M. El-Marakby; Rania M. Hathout; Ismail Taha; Samar Mansour; Nahed D. Mortada (123-138).
Valerate-conjugated chitosan nanoparticles surface decorated with glycyrrhizin augments the cytotoxicity of ferulic acid and successfully targets it to the liver.Display OmittedThe aim of this study was to target a naturally chemotherapeutic agent: ferulic acid to the liver using a biocompatible and an in vivo stable carrier. Accordingly, chitosan as a biopolymer was modified using a hydrophobic moiety and valeric acid in order to increase its in vivo stability. The structure of the newly synthesized product was confirmed using FT-IR and NMR techniques together with the ninhydrin assay. Ferulic acid was conjugated to the modified nanoparticles that were further characterized for particle size, PDI and zeta potential and subjected to ex vivo stability study in serum and cytotoxicity studies in HepG2 cell lines. Furthermore, the nanoparticles were surface-decorated with glycyrrhizin for active liver targeting. The in vivo biodistribution was experimented using radiolabeling assay where the liver scored the highest accumulation of the glycyrrhizin containing nanoparticles after 6 h reaching a value of 13.34% ID/g of the total injected dose of labeled drug compared to drug solution and glycyrrhizin free nanoparticles where the accumulation percent did not exceed 4.19% ID/g and 4.26% ID/g, respectively. As a conclusion, the conducted physico-chemical and biological investigations suggested that the proposed selected system can be efficiently utilized as a successful platform for targeting a natural chemotherapeutic agent viz. ferulic acid to the liver.
Keywords: Chitosan; Nanoparticles; Ferulic acid; Valerate; Glycyrrhizin;

Unmet clinical needs in the treatment of systemic fungal infections: The role of amphotericin B and drug targeting by Raquel Fernández-García; Esther de Pablo; María Paloma Ballesteros; Dolores R. Serrano (139-148).
Display OmittedRecently an increase in both the prevalence and incidence of invasive fungal infections have been reported. The number of fungal species that can cause systemic mycoses are higher and current antifungal therapies are still far from ideal. The emergence of antifungal resistances has a major clinical impact when using azoles and echinocandins leading to possible treatment failure and ultimately putting the patient’s life at risk. Amphotericin B can play a key role in treating severe invasive mycoses as the incidence of antifungal resistance is very low combined with a high efficacy against a wide range of fungi. However, the use of this drug is limited due to its high toxicity and the infusion-related side effects often necessitating patient hospitalisation. New medicines based on lipid-based systems have been commercialised in the last decade, these treatments are able to reduce the toxicity of the drug but intravenous administration is still required. An oral or topically self-administered amphotericin B formulation can overcome these challenges, however such a product is not yet available. Several drug delivery systems such as cochleates, nanoparticulate and self-emulsifying systems are under development in order to enhance the solubility of the drug in aqueous media and promote oral absorption and cutaneous permeation across the skin. In this review, the type of drug delivery system and the effect of particle size on efficacy, toxicity and biodistribution will be discussed.
Keywords: Amphotericin B; AmBisome®; Drug delivery; Candida spp; Nanoparticles; Poly-aggregates; Nephrotoxicity;

Feasibility of mini-tablets as a flexible drug delivery tool by Biplob Mitra; Jessica Chang; Sy-Juen Wu; Chad N. Wolfe; Robert L. Ternik; Thomas Z. Gunter; Michael C. Victor (149-159).
Display OmittedMini-tablets have potential applications as a flexible drug delivery tool in addition to their generally perceived use as multi-particulates. That is, mini-tablets could provide flexibility in dose finding studies and/or allow for combination therapies in the clinic. Moreover, mini-tablets with well controlled quality attributes could be a prudent choice for administering solid dosage forms as a single unit or composite of multiple mini-tablets in patient populations with swallowing difficulties (e.g., pediatric and geriatric populations). This work demonstrated drug substance particle size and concentration ranges that achieve acceptable mini-tablet quality attributes for use as a single or composite dosage unit. Immediate release and orally disintegrating mini-tablet formulations with 30 μm to 350 μm (particle size d90) acetaminophen and Compap™ L (90% acetaminophen) at concentrations equivalent to 6.7% and 26.7% acetaminophen were evaluated. Mini-tablets achieved acceptable weight variability, tensile strength, friability, and disintegration time at a reasonable solid fraction for each formulation. The content uniformity was acceptable for mini-tablets of 6.7% formulations with ≤170 μm drug substance, mini-tablets of all 26.7% formulations, and composite dosage units containing five or more mini-tablets of any formulation. Results supported the manufacturing feasibility of quality mini-tablets, and their applicability as a flexible drug delivery tool.
Keywords: Mini-tablets; Orally disintegrating mini-tablets; Drug delivery tool; Dose flexibility; Fixed dose combination; Content uniformity; Physico-mechanical attributes;

Surface modification of acetaminophen particles by atomic layer deposition by Tommi O. Kääriäinen; Marianna Kemell; Marko Vehkamäki; Marja-Leena Kääriäinen; Alexandra Correia; Hélder A. Santos; Luis M. Bimbo; Jouni Hirvonen; Pekka Hoppu; Steven M. George; David C. Cameron; Mikko Ritala; Markku Leskelä (160-174).
Display OmittedActive pharmaceutical ingredients (APIs) are predominantly organic solid powders. Due to their bulk properties many APIs require processing to improve pharmaceutical formulation and manufacturing in the preparation for various drug dosage forms. Improved powder flow and protection of the APIs are often anticipated characteristics in pharmaceutical manufacturing. In this work, we have modified acetaminophen particles with atomic layer deposition (ALD) by conformal nanometer scale coatings in a one-step coating process. According to the results, ALD, utilizing common chemistries for Al2O3, TiO2 and ZnO, is shown to be a promising coating method for solid pharmaceutical powders. Acetaminophen does not undergo degradation during the ALD coating process and maintains its stable polymorphic structure. Acetaminophen with nanometer scale ALD coatings shows slowed drug release. ALD TiO2 coated acetaminophen particles show cytocompatibility whereas those coated with thicker ZnO coatings exhibit the most cytotoxicity among the ALD materials under study when assessed in vitro by their effect on intestinal Caco-2 cells.
Keywords: Atomic layer deposition; Acetaminophen; Drug release; Cytocombatibility; Drug delivery system;

Display OmittedAerobic vaginitis (AV) leads to uterus deep infection or preterm birth. Antibacterial agents are not optimal therapeutics of AV. Here, we report a series of temperature-sensitive in situ forming acidic buffered gels for topical treatment of AV, involving lactate, acetate, and citrate gels at pH 3.5, 5.0, and 6.5. AV rat models were prepared following vaginal infection with Staphylococcus aureus and Escherichia coli. In vitro/in vivo studies of the buffered gels were performed compared with ofloxacin gels and blank gels. All the buffered gels showed the lower in vitro antibacterial activities than ofloxacin gels but the better in vivo anti-S. aureus effects and similar anti-E. coli effects. The buffered gels improved Lactobacillus growth in the vaginas. Both the healthy rat vaginal pH and the pH of rat vaginas treated with the buffered gels were about 6.5 though the AV rat models or ones treated with ofloxacin gels still remained at the high pH more than 7.0. After treatments with the buffered gels, the vaginal smears changed to a clean state nearly without aerobic bacteria, the vaginal tissues were refreshed, and the immunoreactions were downregulated. The acidic buffered gels bring rapid decrease of local vaginal pH, high antibacterial activities, improvement of probiotics, and alleviation of inflammation. They are simple, highly efficient, and safe anti-AV formulations.
Keywords: Aerobic vaginitis; Buffer; Escherichia coli; Gel; Lactobacillus; Microenvironment; Staphylococcus aureus;

Enhanced release of poorly water-soluble drugs from synergy between mesoporous magnesium carbonate and polymers by Jiaojiao Yang; Caroline Alvebratt; Peng Zhang; Teresa Zardán Gómez de la Torre; Maria Strømme; Christel A.S. Bergström; Ken Welch (183-190).
Display OmittedThe need to combat poor water solubility has increased interest in supersaturating drug delivery systems. In this study, amorphous mesoporous magnesium carbonate (MMC) was used as a drug carrier to achieve supersaturation of tolfenamic acid and rimonabant, two drug compounds with low aqueous solubility. The potential synergy between MMC and hydroxypropyl methylcellulose (HPMC), a polymer commonly included as a precipitation inhibitor in drug delivery systems, was explored with the aim of extending the time that high supersaturation levels were maintained. Release was studied under physiological conditions using USP-2 dissolution baths. A new small-scale method was developed to enable measurement of the initial drug release occurring when the MMC is immersed in the water phase. It was shown that MMC and HPMC together resulted in significant supersaturation and that the polymer enabled both the achievement of a higher API concentration and extension of the supersaturation period. The new small-scale release method showed that the release was linearly increasing with the dose and that similar release rates were observed for the two model compounds. It was hence concluded that the MMC release was diffusion limited for the compounds explored.
Keywords: Magnesium carbonate; Mesoporous; Hydroxypropyl methylcellulose; Tolfenamic acid; Rimonabant; Supersaturation;

Tailoring the supramolecular structure of amphiphilic glycopolypeptide analogue toward liver targeted drug delivery systems by Aisha Roshan Mohamed Wali; Jie Zhou; Shengnan Ma; Yiyan He; Dong Yue; James Zhenggui Tang; Zhongwei Gu (191-202).
Display OmittedAmphiphilic glycopolypeptide analogues have harboured great importance in the development of targeted drug delivery systems. In this study, lactosylated pullulan-graft-arginine dendrons (LP-g-G3P) was synthesized using Huisgen azide-alkyne 1,3-dipolar cycloaddition between lactosylated pullulan and generation 3 arginine dendrons bearing Pbf and Boc groups on the periphery. Hydrophilic lactosylated pullulan was selected for amphiphilic modification, aiming at specific lectin recognition. Macromolecular structure of LP-g-G3P combined alkyl, aromatic, and peptide dendritic hydrophobic moieties and was able to self-assemble spontaneously into core-shell nanoarchitectures with small particle sizes and low polydispersity in the aqueous media, which was confirmed by CAC, DLS and TEM. Furthermore, the polyaromatic anticancer drug (doxorubicin, DOX) was selectively encapsulated in the hydrophobic core through multiple interactions with the dendrons, including π-π interactions, hydrogen bonding and hydrophobic interactions. Such multiple interactions had the merits of enhanced drug loading capacity (16.89 ± 2.41%), good stability against dilution, and excellent sustained release property. The cell viability assay presented that LP-g-G3P nanoparticles had an excellent biocompatibility both in the normal and tumor cells. Moreover, LP-g-G3P/DOX nanoparticles could be effectively internalized into the hepatoma carcinoma cells and dramatically inhibited cell proliferation. Thus, this approach paves the way to develop amphiphilic and biofunctional glycopolypeptide-based drug delivery systems.
Keywords: Amphiphilic polysaccharide; Peptide dendrons; Glycopolypeptide; Sustained release; Targeted drug delivery;

Chitosan and hyaluronan coated liposomes for pulmonary administration of curcumin by Maria Manconi; Maria Letizia Manca; Donatella Valenti; Elvira Escribano; Hervé Hillaireau; Anna Maria Fadda; Elias Fattal (203-210).
Display OmittedAiming at improving the nebulization performances and lung antioxidant protection of curcumin, chitosan or hyaluronan-coated liposomes were prepared and their characteristics and performances were compared with that of uncoated liposomes. Curcumin loaded liposomes displayed a diameter lower than 100 nm, the coating with both polymers led to a small increase of vesicle size around 130 nm and the zeta potential turned to positive values using chitosan while remained negative using hyaluronan. Chitosan allowed the formation of more lamellar and stiffer vesicles with a higher bilayer thickness (dB  ∼ 59 Ǻ) with respect to the uncoated liposomes, whereas hyaluronan allowed the interdigitation of the bilayers (dB  ∼ 47 Ǻ) due to the polymer intercalation between phospholipid head groups resulting in vesicles mainly organized in uncorrelated bilayers. Both polymer coatings, especially hyaluronan, greatly improved the stability of the vesicles, especially during the nebulization process, promoting the deposition of the phytodrug in the furthest stages of the impactor in high amount (≥50%). Polymer coated vesicles were biocompatible and improved the curcumin ability to protect A549 cells from the oxidative stress induced by hydrogen peroxide, restoring healthy conditions (cell relative metabolic activity 100%). In particular, a synergic effect of curcumin and hyaluronan was observed resulting in a proliferative effect and a subsequent further enhancement of cell relative metabolic activity up to 120%.
Keywords: Hydrophilic polymers; Coated liposomes; Oxidative stress; Pulmonary delivery; A549 cells;

Display OmittedThis study evaluated the fasted state gastrointestinal behavior of the lipophilic drug itraconazole, orally administered to healthy volunteers as either a solid dispersion (Sporanox® capsules) or a cyclodextrin-based solution (Sporanox® solution). Following intake of the drug products, gastric and duodenal fluids were aspirated and analyzed for itraconazole concentration, total content and solubilizing capacity. Release of itraconazole from the solid dispersion generated high and metastable supersaturated levels in the stomach, but the dissolved fraction in the duodenum remained extremely low (median 2.5%). After intake of the itraconazole solution, precipitation was limited in the stomach but pronounced in the small intestine. Still, the dissolved fraction of itraconazole in the duodenum (median 38%) appeared much higher than after intake of the solid dispersion, possibly explaining the improved absorption of itraconazole from the solution. As for the solid dispersion, the absorption-enabling ability of the solution appeared mainly related to increased intraluminal concentrations by means of supersaturation. Cyclodextrin-based solubilization of itraconazole occurred only in the case of limited intraluminal dilution, but did not further enhance itraconazole absorption. The obtained data will help to understand critical aspects of supersaturating drug delivery systems and act as direct reference for the optimization of in vitro simulation tools for gastrointestinal drug behavior.
Keywords: Intestinal absorption; Itraconazole; Solid dispersion; Cyclodextrin-based oral solution; Supersaturation; Precipitation;

Development of light-driven gas-forming liposomes for efficient tumor treatment by Jae Min Lee; Yu Seok Youn; Eun Seong Lee (218-225).
Display OmittedIn this study, we report a gas-forming liposome containing 1H-1H-2H-perfluoro-1-hexene (PFH) and gold nanoparticles (AuNPs). These liposomes were rapidly destabilized by external near-infrared (NIR) light, as a result of the vaporization of PFH influenced by an AuNPs-mediated photothermal event. In particular, these liposomes showed the triggered release of the encapsulated d-(KLAKLAK)2 peptide drug. The experimental results demonstrated that the light-irradiated liposomes significantly enhanced in vitro photothermal and d-(KLAKLAK)2 peptide-mediated cell death of CAOV-3 tumor cells.
Keywords: Gas-forming liposome; Gold nanoparticles (AuNPs); Perfluorohexene; d-(KLAKLAK)2 peptide drug;

Improved release of triamcinolone acetonide from medicated soft contact lenses loaded with drug nanosuspensions by Eva García-Millán; Mónica Quintáns-Carballo; Francisco Javier Otero-Espinar (226-236).
Display OmittedDrug nanosuspensions (NSs) show a significant potential to improve loading and release properties of the poorly water soluble drug triamcinolone acetonide (TA) from poly(hydroxyethyl methacrylate) (pHEMA) soft contact lenses. In this work, TA NSs were developed by a controlled precipitation method using a fractional factorial Plackett–Burmann design. Poloxamer 407 (PL) and polyvinyl alcohol (PVA) as stabilizing agents were selected. NSs were characterized in terms of their drug content, particle size and morphology. Results indicate that all studied factors, except homogenization speed and sonication, have significant influence on the drug incorporation yield into NSs. Drug nanoparticles showed an interesting size that may be suitable for their incorporation into topical ocular drug delivery systems, as hydrogels.pHEMA hydrogels and daily-wear Hilafilcon B commercial contact lenses (SCLs) were employed to study TA loading capacity and drug release properties using NSs as loading system. Hydrogels have been synthesised by copolymerization of 2-hydroxyethyl methacrylate (HEMA) with methacrylic acid (MA) in accordance with a previous work (García-Millán et al., 2015). Both synthesised hydrogels and SCLs were characterized in terms of their mechanical and physical properties and TA loading and release properties. Selected TA NS was further characterized by studying its physical-chemical stability during the loading process.Results show that the use of TA NSs as loading medium significantly increases drug loading capacity and release of soft contact lenses in comparison with drug saturated solution. Synthesised pHEMA hydrogels and SCLs lenses have good properties as ophthalmic drug delivery systems, but SCLs load higher quantities of drug and release TA in shorter time periods than synthesised pHEMA hydrogel.
Keywords: Medicated soft contact lenses; Nanosuspensions; Ocular; pHEMA hydrogels; Triamcinolone acetonide; Ocular drug release;

Dual-functional nanoparticles for precise drug delivery to Alzheimer’s disease lesions: Targeting mechanisms, pharmacodynamics and safety by Xiaoyao Zheng; Chi Zhang; Qian Guo; Xu Wan; Xiayan Shao; Qingfeng Liu; Qizhi Zhang (237-248).
Display OmittedAlzheimer’s disease (AD) is the most common form of dementia and is characterized by the cerebral accumulation of extracellular amyloid plaques. In a previous study, this histopathological hallmark was used as a target on a dual-functional nanoparticle (TQNP) to deliver biotechnological drugs, such as the H102 peptide, a β-sheet breaker, to AD lesions precisely. This delivery system could reduce the amyloid-β (Aβ) burden in the brains of AD model mice, as well as ameliorated the memory impairment of the mice. Regretfully, the mechanism how nanoparticles penetrated the BBB and subsequently targeted to the plaques is still unclear. In this study, the internalization, subcellular fate and transportation of the nanoparticles on bEnd.3 cells and an in vitro BBB model, demonstrated that TQNP could be taken up through various routes, including caveolae-mediated endocytosis, suggesting that some of TQNP were able to cross the BBB intact. Then, the TQNP were visualized to specifically bind to the Aβ plaques. TQNP targeting to amyloid plaques might lead to enhanced therapeutic efficacy, which was further evaluated in APP/PS1 transgenic mice. The TQNP/H102 obtained better ability in decreasing amyloid plaques, increasing Aβ-degrading enzymes, reducing tau protein phosphorylation, protecting synapses and improving the spatial learning and memory of transgenic mice than nanoparticles modified with a single ligand. And good biocompatibility of TQNP was indicated with subacute toxicity assays. In conclusion, TQNP was a valuable nanodevice for the precise delivery for biotechnological drugs to treat AD.
Keywords: Dual-functional nanoparticles; BBB transport mechanism; Amyloid plaque; H102 peptide; Transgenic mice; Alzheimer’s disease;

Optimization of critical quality attributes in continuous twin-screw wet granulation via design space validated with pilot scale experimental data by Huolong Liu; S.C. Galbraith; Brendon Ricart; Courtney Stanton; Brandye Smith-Goettler; Luke Verdi; Thomas O’Connor; Sau Lee; Seongkyu Yoon (249-263).
Display OmittedIn this study, the influence of key process variables (screw speed, throughput and liquid to solid (L/S) ratio) of a continuous twin screw wet granulation (TSWG) was investigated using a central composite face-centered (CCF) experimental design method. Regression models were developed to predict the process responses (motor torque, granule residence time), granule properties (size distribution, volume average diameter, yield, relative width, flowability) and tablet properties (tensile strength). The effects of the three key process variables were analyzed via contour and interaction plots. The experimental results have demonstrated that all the process responses, granule properties and tablet properties are influenced by changing the screw speed, throughput and L/S ratio. The TSWG process was optimized to produce granules with specific volume average diameter of 150 μm and the yield of 95% based on the developed regression models. A design space (DS) was built based on volume average granule diameter between 90 and 200 μm and the granule yield larger than 75% with a failure probability analysis using Monte Carlo simulations. Validation experiments successfully validated the robustness and accuracy of the DS generated using the CCF experimental design in optimizing a continuous TSWG process.
Keywords: Continuous twin screw wet granulation; Design of experiment (DoE); Monte Carlo simulation; Design space;

Display OmittedBiocompatible, biodegradable polymers are commonly used as excipients to improve the drug delivery properties of aerosol formulations, in which acetalated dextran (Ac-Dex) exhibits promising potential as a polymer in various therapeutic applications. Despite this promise, there is no comprehensive study on the use of Ac-Dex as an excipient for dry powder aerosol formulations. In this study, we developed and characterized pulmonary drug delivery aerosol microparticle systems based on spray-dried Ac-Dex with capabilities of (1) delivering therapeutics to the deep lung, (2) targeting the particles to a desired location within the lungs, and (3) releasing the therapeutics in a controlled fashion. Two types of Ac-Dex, with either rapid or slow degradation rates, were synthesized. Nanocomposite microparticle (nCmP) and microparticle (MP) systems were successfully formulated using both kinds of Ac-Dex as excipients and curcumin as a model drug. The resulting MP were collapsed spheres approximately 1 μm in diameter, while the nCmP were similar in size with wrinkled surfaces, and these systems dissociated into 200 nm nanoparticles upon reconstitution in water. The drug release rates of the Ac-Dex particles were tuned by modifying the particle size and ratio of fast to slow degrading Ac-Dex. The pH of the environment was also a significant factor that influenced the drug release rate. All nCmP and MP systems exhibited desirable aerodynamic diameters that are suitable for deep lung delivery (e.g. below 5 μm). Overall, the engineered Ac-Dex aerosol particle systems have the potential to provide targeted and effective delivery of therapeutics into the deep lung.
Keywords: Acetalated dextran; Nanocomposite microparticles; Microparticles; Pulmonary delivery; Spray drying; Controlled release;

EXCI-CEST: Exploiting pharmaceutical excipients as MRI-CEST contrast agents for tumor imaging by Dario Livio Longo; Fatima Zzahra Moustaghfir; Alexandre Zerbo; Lorena Consolino; Annasofia Anemone; Martina Bracesco; Silvio Aime (275-281).
Display OmittedChemical Exchange Saturation Transfer (CEST) approach is a novel tool within magnetic resonance imaging (MRI) that allows visualization of molecules possessing exchangeable protons with water. Many molecules, employed as excipients for the formulation of finished drug products, are endowed with hydroxyl, amine or amide protons, thus can be exploitable as MRI-CEST contrast agents. Their high safety profiles allow them to be injected at very high doses. Here we investigated the MRI-CEST properties of several excipients (ascorbic acid, sucrose, N-acetyl-d-glucosamine, meglumine and 2-pyrrolidone) and tested them as tumor-detecting agents in two different murine tumor models (breast and melanoma cancers). All the investigated molecules showed remarkable CEST contrast upon i.v. administration in the range 1–3 ppm according to the type of mobile proton groups. A marked increase of CEST contrast was observed in tumor regions up to 30 min post injection. The combination of marked tumor contrast enhancement and lack of toxicity make these molecules potential candidates for the diagnosis of tumors within the MRI-CEST approach.
Keywords: Excipients; MRI; CEST; Tumor; Imaging; Chemical exchange saturation transfer;

Display OmittedThe coating layer thickness of enteric-coated tablets is a key factor that determines the drug dissolution rate from the tablet. Near-infrared spectroscopy (NIRS) enables non-destructive and quick measurement of the coating layer thickness, and thus allows the investigation of the relation between enteric coating layer thickness and drug dissolution rate. Two marketed products of aspirin enteric-coated tablets were used in this study, and the correlation between the predicted coating layer thickness and the obtained drug dissolution rate was investigated. Our results showed correlation for one product; the drug dissolution rate decreased with the increase in enteric coating layer thickness, whereas, there was no correlation for the other product. Additional examination of the distribution of coating layer thickness by X-ray computed tomography (CT) showed homogenous distribution of coating layer thickness for the former product, whereas the latter product exhibited heterogeneous distribution within the tablet, as well as inconsistent trend in the thickness distribution between the tablets. It was suggested that this heterogeneity and inconsistent trend in layer thickness distribution contributed to the absence of correlation between the layer thickness of the face and side regions of the tablets, which resulted in the loss of correlation between the coating layer thickness and drug dissolution rate. Therefore, the predictability of drug dissolution rate from enteric-coated tablets depended on the homogeneity of the coating layer thickness. In addition, the importance of micro analysis, X-ray CT in this study, was suggested even if the macro analysis, NIRS in this study, are finally applied for the measurement.
Keywords: Enteric coated tablet; Eudragit L30D-55; Coating layer thickness; Dissolution; near infrared spectroscopy; X-ray computed tomography;