International Journal of Pharmaceutics (v.486, #1-2)
EDITORIAL BOARD (iii).
Specific in vitro binding of a new 99mTc-radiolabeled derivative of the C-terminal decapeptide of prothymosin alpha on human neutrophils by Chrysoula-Evangelia Karachaliou; Christos Liolios; Charalampos Triantis; Christos Zikos; Pinelopi Samara; Ourania E. Tsitsilonis; Hubert Kalbacher; Wolfgang Voelter; Minas Papadopoulos; Ioannis Pirmettis; Evangelia Livaniou (1-12).
Display OmittedProthymosin alpha (ProTα) is a conserved mammalian polypeptide with intracellular functions associated with cell proliferation and apoptosis and an extracellular role associated with immunopotentiation. The N-terminal fragment [1–28], which is identical with the immunostimulating peptide thymosin α1 (Tα1), was earlier considered as the immunoactive region of the polypeptide; however, recent data suggest that ProTα may exert a discrete immunomodulating action through its central or C-terminal region, via targeting Toll-like receptor- 4 (TLR4). In this work, a derivative of the C-terminal fragment ProTα[100-109] (ProTα-D1) that can be radiolabeled with 99mTc was developed. The biological activity of the non-radioactive 185/187rhenium-complex of this derivative ([185/187Re]ProTα-D1, structurally similar with [99mTc]ProTα-D1) was verified through suitable in vitro bioassays on human neutrophils. Subsequent cell-binding studies revealed specific, time-dependent and saturable binding of [99mTc]ProTα-D1 on neutrophils, which was inhibited by intact ProTα and ProTα[100-109], as well as by a “prototype” TLR4-ligand (lipopolysaccharide from Escherichia coli). Overall, our results support the existence of ProTα-binding sites on human neutrophils, recognizing [99mTc]ProTα-D1, which might involve TLR4. [99mTc]ProTα-D1 may be a useful tool for conducting further in vitro and in vivo studies, aiming to elucidate the extracellular mode of action of ProTα and, eventually, develop ProTα-based immunotherapeutics.
Keywords: Prothymosin alpha (ProTα); Synthetic ProTα-fragments; 99mTc-radiolabeling; Human neutrophils; Cell-binding studies;
Optimization of a pharmaceutical tablet formulation based on a design space approach and using vibrational spectroscopy as PAT tool by Pierre-François Chavez; Pierre Lebrun; Pierre-Yves Sacré; Charlotte De Bleye; Lauranne Netchacovitch; Serge Cuypers; Jérôme Mantanus; Henri Motte; Martin Schubert; Brigitte Evrard; Philippe Hubert; Eric Ziemons (13-20).
Display OmittedThe aim of the present study was to optimize a tablet formulation using a quality by design approach. The selected methodology was based on the variation of the filler grade, taking into account the particle size distribution (PSD) of active pharmaceutical ingredient (API) in order to improve five critical quality attributes (CQAs). Thus, a mixture design of experiments (DoE) was performed at pilot scale. The blending step was monitored using near infrared (NIR) spectroscopy as process analytical technology tool enabling real-time qualitative process monitoring. Furthermore, some tablets were analyzed by Raman imaging to evaluate the API distribution within the samples. Based on the DoE results, design spaces were computed using a risk-based Bayesian predictive approach to provide for each point of the experimental domain the expected probability to get the five CQAs jointly within the specifications in the future. Finally, the optimal conditions of the identified design space were successfully validated. In conclusion, a design space approach supported by NIR and Raman spectroscopy was able to define a blend that complies with the target product profile with a quantified guarantee or risk.
Keywords: Design space; Quality by design; Process analytical technology; Vibrational spectroscopy; Optimization; Pharmaceutical tablet formulation;
Influence of salt type and ionic strength on self-assembly of dextran sulfate-ciprofloxacin nanoplexes by Marika Kutscher; Wean Sin Cheow; Vera Werner; Udo Lorenz; Knut Ohlsen; Lorenz Meinel; Kunn Hadinoto; Oliver Germershaus (21-29).
Display OmittedWe evaluated an analytical setup to identify optimal preparation conditions for nanoplex formation of small molecule drugs and polyelectrolytes using ciprofloxacin (CIP) and dextran sulfate (DS) as model compounds. The suitability of isothermal titration calorimetry (ITC) as a screening tool for rational formulation optimization was assessed. Besides ITC, static and dynamic light scattering, zeta potential measurements and scanning electron microscopy were applied to analyze the influence of different salt types and ionic strengths on CIP/DS nanoplex formation. The addition of low amounts of salt, especially 0.1 M NaCl, improved the formation of CIP/DS nanoplexes. The presence of low amounts of salt led to smaller and more numerous particles of higher uniformity but had no influence on the release of CIP from nanoplexes. Furthermore, the molar range, within which efficient complexation was achieved, was broader in the presence of 0.1 M NaCl than in the absence of salt with overall comparable complexation efficiency. Importantly, binding affinity correlated with particle shape and morphology, potentially enabling optimization of critical quality attributes based on ITC data. Altogether, ITC along with supplemental methods is a versatile screening tool for the evaluation of nanoplex formulation conditions regarding mixing ratio, salt type and ionic strength.
Keywords: Polyelectrolyte complex; Ciprofloxacin; Dextran sulfate; Isothermal titration calorimetry;
Tuning dual-drug release from composite scaffolds for bone regeneration by J.L. Paris; J. Román; M. Manzano; M.V. Cabañas; M. Vallet-Regí (30-37).
Display OmittedThis work presents the tuning of drug-loaded scaffolds for bone regeneration as dual-drug delivery systems. Two therapeutic substances, zoledronic acid (anti-osteoporotic drug) and ibuprofen (anti-inflammatory drug) were successfully incorporated in a controlled manner into three dimensional designed porous scaffolds of apatite/agarose composite. A high-performance liquid chromatography method was optimized to separate and simultaneously quantify the two drugs released from the dual-drug codelivery system. The multifunctional porous scaffolds fabricated show a very rapid delivery of anti-inflammatory (interesting to reduce inflammation after implantation), whereas the anti-osteoporotic drug showed sustained release behaviour (important to promote bone regeneration). Since ibuprofen release was faster than desired, this drug was encapsulated in chitosan spheres which were then incorporated into the scaffolds, obtaining a release profile suitable for clinical application. The results obtained open the possibility to simultaneously incorporate two or more drugs to an osseous implant in a controlled way improving it for bone healing application.
Keywords: Dual-drug delivery system; Designed porous scaffold; Ibuprofen; Zoledronic acid; Co-delivery release; Tissue engineering;
In-situ forming composite implants for periodontitis treatment: How the formulation determines system performance by M.P. Do; C. Neut; H. Metz; E. Delcourt; K. Mäder; J. Siepmann; F. Siepmann (38-51).
Display OmittedPeriodontitis is the primary cause of tooth loss in adults and a very wide-spread disease. Recently, composite implants, based on a drug release rate controlling polymer and an adhesive polymer, have been proposed for an efficient local drug treatment. However, the processes involved in implant formation and the control of drug release in these composite systems are complex and the relationships between the systems’ composition and the implants’ performance are yet unclear. In this study, advanced characterization techniques (e.g., electron paramagnetic resonance, EPR) were applied to better understand the in-situ forming implants based on: (i) different types of poly(lactic-co-glycolic acid) (PLGA) as drug release rate controlling polymers; (ii) hydroxypropyl methylcellulose (HPMC) as adhesive polymer; and (iii) doxycycline or metronidazole as drugs. Interestingly, HPMC addition to shorter chain PLGA slightly slows down drug release, whereas in the case of longer chain PLGA the release rate substantially increases. This opposite impact on drug release was rather surprising, since the only difference in the formulations was the polymer molecular weight of the PLGA. Based on the physico-chemical analyses, the underlying mechanisms could be explained as follows: since longer chain PLGA is more hydrophobic than shorter chain PLGA, the addition of HPMC leads to a much more pronounced facilitation of water penetration into the system (as evidenced by EPR). This and the higher polymer lipophilicity result in more rapid PLGA precipitation and a more porous inner implant structure. Consequently, drug release is accelerated. In contrast, water penetration into formulations based on shorter chain PLGA is rather similar in the presence and absence of HPMC and the resulting implants are much less porous than those based on longer chain PLGA.
Keywords: In-situ forming implant; Periodontitis; PLGA; EPR; Doxycycline;
Feasibility study for intraepidermal delivery of proteins using a solid microneedle array by Madeleine Witting; Katja Obst; Markus Pietzsch; Wolfgang Friess; Sarah Hedtrich (52-58).
Display OmittedSolid microneedles (MN) are a promising tool for dermal drug delivery. Particular focus lies on the field of vaccination due to pain-free, safe, hygienic and patient compliant antigen deposition. Diverse coating techniques and formulations have been developed to preserve vaccine activity and to enable targeted drug deposition in the skin. Process and long-term storage stability of coated MN, however, have not yet been studied in detail. Hence, a feasibility study was conducted determining the appropriate needle length (300 μm) for local intraepidermal protein delivery. Moreover, a protein-stabilizing coating formulation was developed. Coating of the MN resulted in protein concentrations between 10 and 23 μg, 90% of the bioactivity of the model protein asparaginase was maintained for 3 months. Skin experiments verified the intraepidermal deposition of 68.0 ± 11.7% of the coated model protein after single application. Slightly increased interleukin 8 levels right after MN insertion indicated minor skin irritation due to the mechanical piercing stress. Thus, specifically highlighting protein stabilization during storage, we demonstrated that selective intraepidermal deposition of proteins or peptides’ using solid MN is a feasible approach.
Keywords: Solid microneedle array; Proteins; Coating formulation; Protein stability; Human reconstructed skin; Skin irritation;
Casein/pectin nanocomplexes as potential oral delivery vehicles by Yangchao Luo; Kang Pan; Qixin Zhong (59-68).
Display OmittedDelivery systems prepared with natural biopolymers are of particular interests for applications in food, pharmaceutics and biomedicine. In this study, nanocomplex particles of sodium caseinate (NaCas) and pectin were fabricated and investigated as potential oral delivery vehicles. Nanocomplexes were prepared with three mass ratios of NaCas/pectin by acidification using glucono-δ-lactone and thermal treatment. NaCas/pectin at 1:1 mass ratio resulted in dispersions with the lowest turbidity and the smallest and most uniform nanocomplexes. Thermal treatment at 85 °C for 30 min facilitated the formation of stable, compact, and spherical nanocomplexes. Heating not only greatly increased the yield of nanocomplexes but also significantly improved the encapsulation capability of rutin studied as a model compound. Pectin in nanocomplexes delayed the hydrolysis of NaCas by pepsin at gastric conditions and enabled the controlled release of most rutin in simulated intestinal conditions. The nanocomplexes based on food-sourced biopolymers have promising features for oral delivery of nutrients and medicines.
Keywords: Casein; Pectin; Nanocomplexes; Delayed gastric digestion; Oral delivery vehicles;
Evaluation of pharmacokinetic properties and anaesthetic effects of propofol in a new perfluorohexyloctane (F6H8) emulsion in rats – A comparative study by Charalambos Tsagogiorgas; Sonja Theisinger; Elisabeth Heesch; Jörg Krebs; René Holm; Grietje Beck; Benito Yard (69-76).
Display OmittedPropofol (2,6-diisopropylphenol) is a safe and widely used anaesthetic, but due to low water solubility and high lipophilicity a difficult compound to formulate. The solubility of propofol in the semifluorinated alkane perfluorohexyloctane (F6H8) is very high (>300 mg/ml). In the present work we investigate if a F6H8-based emulsion could be used as a new intravenous drug delivery system for propofol from a pharmacokinetic, pharmacodynamic and safety point of view. The pharmacokinetic parameters were evaluated after an intravenous bolus injection of either Disoprivan® or a F6H8-based propofol emulsion in Wistar rats. The onset and end of sedation after multiple dosings (5, 10 and 15 mg/kg bw) were examined. Clinical chemistry and histology were assessed. No significant difference was found for any of the pharmacokinetic parameters. No differences in the onset nor the end of sedation in the tested dosages could be detected. Histology scores revealed no differences. A slightly increased alanine aminotransferase (ALT) was measured after multiple application of the F6H8-propofol emulsion. In conclusion, the F6H8-propofol emulsion showed no significant different pharmacokinetics and sedation properties, compared to a commercial soy-based propofol emulsion. Further, no toxic effects could be detected on the F6H8 emulsion indicating it was a safe excipient in rats.
Keywords: Drug delivery; Propofol; Semifluorinated alkane; F6H8; Perfluorocarbon; Emulsion;
Novel semisolid SNEDDS based on PEG-30-di-(polyhydroxystearate): Progesterone incorporation and in vitro digestion by Tamer H. Hassan; Karsten Mäder (77-87).
Display OmittedThe aim of this work is to study the digestibility of PEG-30-di-(polyhydroxystearate) (Cithrol® DPHS) and its semisolid novel self-nanoemulsifying drug delivery systems (SNEDDS). Furthermore, the SNEDDS-mediated solubility enhancement of the poorly water-soluble drug Progesterone was evaluated in different media. Additionally, the impact of digestion on Progesterone solubilization was investigated in vitro by a pancreatin digestion assay. The Progesterone-loaded semisolid self-nanoemulsifying formulation (F2) was comprehensively characterized by photon correlation spectroscopy (PCS), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and Fourier transform infrared spectroscopy (FTIR). SNEDDS were able to enhance the equilibrium solubility of Progesterone at various media. Only a minor part of Cithrol® DPHS was digested by pancreatin (less than 6%). Furthermore, protection of Progesterone against digestion-mediated precipitation was observed. Therefore, DPHS containing SNEDDS are attractive candidates for the development of bio robust drug delivery systems for the oral delivery of poorly soluble drugs.
Keywords: Semisolid SNEDDS; Cithrol® DPHS; pH-stat; Progesterone; HPTLC; Lipid digestion; Selfemuslifying;
Novel curcumin-loaded gel-core hyaluosomes with promising burn-wound healing potential: Development, in-vitro appraisal and in-vivo studies by Wessam M. El-Refaie; Yosra S.R. Elnaggar; Magda A. El-Massik; Ossama Y. Abdallah (88-98).
Display OmittedDespite its effectiveness, curcumin (Curc) dermal delivery is handicapped by hydrophobicity, high metabolism and poor skin permeation. In this work, the potential of novel self-assembled nanogels, namely gel-core hyaluosome (GC-HS) to enhance Curc delivery to wound sites, enhance healing rate and decrease scar formation was evaluated. Curc–GC-HS were prepared using film hydration technique and evaluated regarding size, zeta potential (ZP), entrapment efficiency (% EE), and in vitro release. Structure elucidation was performed using light, polarizing and transmission electron microscopy (TEM). In-vivo burn-wound healing potential, skin deposition ability and histological study were evaluated using female Sprague Dawley rats. Curc–GC-HS were compared to conventional transfersomal gel (Curc–T-Pl gel), and other conventional gels. Curc–GC-HS showed nanosize (202.7 ± 0.66 nm), negative ZP (−33 ± 2.6 mV) and % EE (96.44 ± 1.29%). TEM revealed discrete vesicles with characteristic bilayer structure. Polarizing microscopy proposed liquid crystalline consistency. Burn-wound healing study showed that Curc–GC-HS was the only system exhibiting marked improvement at day 7 of treatment. At 11th day, Curc–GC-HS treated wounds showed almost normal skin with no scar confirmed by histological analysis. Curc–GC-HS showed five folds higher skin deposition compared to conventional Curc–T-Pl gel. To conclude, novel gel-core hyaluosomes elaborated are promising nanogels able to increase Curc skin penetration and dermal localization while protecting it against degradation. Future perspective encompasses assessing potential of novel nanocarrier for skin cancer therapy.
Keywords: Curcumin; Wound; Burn; Scar; Dermal; Vesicles; Gel-core liposomes; Hyaluronic acid;
Design and preclinical characterization of a novel vaccine adjuvant formulation consisting of a synthetic TLR4 agonist in a thermoreversible squalene emulsion by Jean Haensler; Patricia Probeck; Jin Su; Fabienne Piras; François Dalençon; Jean-François Cotte; Véronique Chambon; Shehzad M. Iqbal; Lynn Hawkins; Nicolas Burdin (99-111).
Different options for incorporating E6020 into AF03, a thermoreversible squalene emulsion adjuvant.Display OmittedWe describe the development, analytical characterization, stability and preclinical efficacy of AF04, a combination adjuvant comprising the synthetic toll-like receptor 4 (TLR4) agonist, E6020, formulated in AF03, a thermoreversible squalene emulsion. By using AF04 with the recombinant major outer membrane protein of Chlamydia trachomatis (Ct-MOMP) and with the recombinant surface glycoprotein gB from human cytomegalovirus (CMV-gB) as model antigens, we show that AF03 and E6020 can synergize to augment specific antibody and Th-1 cellular immune responses in mice. In terms of formulation, we observe that the method used to incorporate E6020 into AF03 affects its partition between the oil and water phases of the emulsion which in turn has a significant impact on the tolerability (IV pyrogenicity test in rabbits) of this novel adjuvant combination.
Keywords: Adjuvant; E6020; AF03; AF04; CMV; Chlamydia trachomatis;
Multivariate modelling to study the effect of the manufacturing process on the complete tablet dissolution profile by Melanie Dumarey; Daniel J. Goodwin; Chris Davison (112-120).
Display OmittedDissolution is invariably identified as a critical quality attribute for oral solid dosage forms, since it is related to when a drug is available for absorption and ultimately exert its effect. In this paper, the influence of granule and compression variability introduced by a design of experiments on the entire dissolution profile was studied with an innovative multivariate tool: bi-directional projections to orthogonal structures (O2PLS). This method enabled a more holistic process understanding compared to conventional approaches where only a single response is used to quantify dissolution. The O2PLS analysis of tablet manufacturing data showed that the disintegration phase of dissolution (10–15 min) was controlled by granule attributes and tablet hardness, while the later phase (15–30 min) was solely controlled by granule attributes. The bidirectional nature of the O2PLS model made it more fit for exploratory purposes, but decreased predictive ability. This approach does not require prior knowledge on the dissolution mechanism and is therefore particularly suited for exploratory studies gaining process understanding during early phase development. The outcome can then guide the selection of attributes, parameters and their ranges for the development of predictive models, e.g., models to define a suitable design space for the process.
Keywords: Dissolution; Oral solid dose; Process understanding; Orthogonal projections to latent structures; Multivariate analysis; Quality by design;
Theophylline–nicotinamide cocrystal formation in physical mixture during storage by Tuomas Ervasti; Jaakko Aaltonen; Jarkko Ketolainen (121-130).
Display OmittedPharmaceutically relevant properties, such as solubility and dissolution rate, of active pharmaceutical ingredients can be enhanced by cocrystal formation. Theophylline and nicotinamide are known to form cocrystals, for example if subjected to solid-state grinding. However, under appropriate conditions, cocrystals can also form in physical mixtures without any mechanical activation. The purpose of this work was to study whether theophylline and nicotinamide could form cocrystals spontaneously, without mechanical activation. Crystalline theophylline and nicotinamide powders were gently mixed manually in a 1:1 molar ratio and stored at different relative humidity and temperature conditions. The solid state of the samples was analyzed by differential scanning calorimetry, Raman spectroscopy and X-ray powder diffractometry. Three different variations of theophylline were used as starting materials, e.g., two size fractions of theophylline anhydrate (large 710 μm–1 mm and small 180–355 μm), and monohydrate (recrystallized from water). As a reference, anhydrous theophylline–nicotinamide cocrystals were prepared by solid-state grinding. The results of this study indicate that theophylline–nicotinamide cocrystals can form without any mechanical activation from physical mixtures of theophylline and nicotinamide during storage. For anhydrous samples, storage humidity was found to be a critical parameter for cocrystal formation. Increasing temperature was also found to have an accelerating effect on the transformation. The effect of particle size of anhydrous theophylline on the transformation rate could not be completely resolved; DSC and Raman indicated slightly faster transformation with a physical mixture prepared from large size fraction of anhydrous theophylline, but the differences were only minor. Cocrystal formation was also observed in the physical mixture prepared from theophylline monohydrate, but the rate was not as high as with samples prepared from anhydrous material.
Keywords: Theophylline; Nicotinamide; Cocrystal; Raman-spectroscopy; DSC; XRPD;
Controlling protein stability: Mechanisms revealed using formulations of arginine, glycine and guanidinium HCl with three globular proteins by Lauren Platts; Robert J. Falconer (131-135).
Display OmittedThree distinct interactions between the amino acid arginine and a protein explain arginine’s ability to modulate the thermal stability of proteins. Arginine’s effect on the protein unfolding behaves like the sum of its constituent parts, glycine and the guanidinium ion. The authors propose that glycine can affect the thermal stability of a protein in two ways: (1) direct interaction with the charged side chains and/or the peptide backbone of the protein which is observed at low concentrations and (2) competition for water between the unfolding protein and the cosolute increasing the energy required to hydrate the unfolding protein. The guanidinium ion acts by (3) direct interaction with apolar regions exposed during unfolding reducing the energy required to hydrate the unfolding protein.
Keywords: Calorimetry; DSC; Aggregation; Stabilization; Formulation; Osmolyte;
Characterising the disintegration properties of tablets in opaque media using texture analysis by Rebekah L. Scheuerle; Stephen E. Gerrard; Richard A. Kendall; Catherine Tuleu; Nigel K.H. Slater; Krishnaa T. Mahbubani (136-143).
Display OmittedTablet disintegration characterisation is used in pharmaceutical research, development, and quality control. Standard methods used to characterise tablet disintegration are often dependent on visual observation in measurement of disintegration times. This presents a challenge for disintegration studies of tablets in opaque, physiologically relevant media that could be useful for tablet formulation optimisation. This study has explored an application of texture analysis disintegration testing, a non-visual, quantitative means of determining tablet disintegration end point, by analysing the disintegration behaviour of two tablet formulations in opaque media. In this study, the disintegration behaviour of one tablet formulation manufactured in-house, and Sybedia Flashtab placebo tablets in water, bovine, and human milk were characterised. A novel method is presented to characterise the disintegration process and to quantify the disintegration end points of the tablets in various media using load data generated by a texture analyser probe. The disintegration times in the different media were found to be statistically different (P < 0.0001) from one another for both tablet formulations using one-way ANOVA. Using the Tukey post-hoc test, the Sybedia Flashtab placebo tablets were found not to have statistically significant disintegration times from each other in human versus bovine milk (adjusted P value 0.1685).
Keywords: Rapidly disintegrating tablet; Texture analysis; Infant drug delivery; Breast milk; Nipple shield delivery system; NSDS;
Controlled drug release from hydrogel-based matrices: Experiments and modeling by Diego CACCAVO; Sara CASCONE; Gaetano LAMBERTI; Anna Angela BARBA (144-152).
Display OmittedControlled release by oral administration is mainly achieved by pharmaceuticals based on hydrogels. Once swallowed, a matrix made of hydrogels experiences water up-take, swelling, drug dissolution and diffusion, polymer erosion. The detailed understanding and quantification of such a complex behavior is a mandatory prerequisite to the design of novel pharmaceuticals for controlled oral delivery. In this work, the behavior of hydrogel-based matrices has been investigated by means of several experimental techniques previously pointed out (gravimetric, and based on texture analysis); and then all the observed features were mathematically described using a physical model, defined and recently improved by our research group (based on balance equations, rate equations and swelling predictions). The agreement between the huge set of experimental data and the detailed calculations by the model is good, confirming the validity of both the experimental and the theoretical approaches.
Keywords: Hydrogels; Water uptake; Texture analysis; Transport phenomena; Modeling;
A comprehensive production method of self-cryoprotected nano-liposome powders by Rikhav P. Gala; Iftikhar Khan; Abdelbary M.A. Elhissi; Mohamed A. Alhnan (153-158).
Display OmittedThis study provided a convenient approach for large scale production of hydrogenated soya phosphatidylcholine nano-liposome powders using beclometasone dipropionate as a model drug and sucrose as proliposome carrier. Fluid-bed coating was employed to manufacture proliposomes by coating sucrose with the phospholipid (5%, 10%, 15% and 20% weight gains), followed by hydration, size reduction using high pressure homogenization, and freeze-drying to yield stable nano-vesicles. High pressure homogenization was compared with probe-sonication in terms of liposome size, zeta potential and drug entrapment. Furthermore, the effect of freeze-drying on vesicle properties generated using both size reduction methods was evaluated. Results have shown that high-pressure homogenization followed by freeze-drying and rehydration tended to yield liposomes smaller than the corresponding vesicles downsized via probe-sonication, and all size measurements were in the range of 72.64–152.50 nm, indicating that freeze-drying was appropriate, regardless of the size reduction technique. The liposomes, regardless of size reduction technique and freeze drying had slightly negative zeta potential values or were almost neutral in surface charge. The entrapment efficiency of BDP in homogenized liposomes was found to increase following freeze-drying, hence the drug entrapment efficiency values in rehydrated liposomes were 64.9%, 57%, 69.5% and 64.5% for 5%, 10%, 15% and 20% weight gains respectively. In this study, we have reported a reliable production method of nano-liposomes based on widely applicable industrial technologies such as fluid-bed coating, high pressure homogenization and freeze-drying. Moreover, sucrose played a dual role as a carrier in the proliposome formulations and as a cryoprotectant during freeze-drying.
Keywords: Homogenizer; Scale-up; Asthma; Cortisones; Aerosol; Inhalation;
Optimization and dissolution performance of spray-dried naproxen nano-crystals by Sumit Kumar; Jie Shen; Banu Zolnik; Nakissa Sadrieh; Diane J. Burgess (159-166).
Display OmittedThe purpose of this study was to investigate the in vitro dissolution performance of the different sized spray-dried nano-crystalline powders of naproxen. A DoE approach was used to formulate and optimize nano-crystalline suspensions. The critical wet milling operation parameters were i.e., drug concentration, drug-to-stabilizer ratio, stabilizer type (HPMC E15 or Tween 80) and milling intensity. The nano-crystalline suspensions were optimized for size and physical stability and then spray-dried to obtain nano-crystalline powders. Trehalose and lactose were investigated as spray-drying auxiliary excipients to achieve non-aggregating powders. Particle size, DSC and PXRD were utilized for characterization of powder formulations. A modified USP apparatus II was utilized to determine the in vitro release/dissolution of powder formulations. The size of the nano-crystalline suspensions was dependent on drug concentration and milling intensity. HPMC E15 containing formulations were better in terms of the spray-dried powder yield compared to Tween 80 containing formulations. Trehalose was selected to formulate non-aggregating nano-crystalline powders. No polymorphic changes were observed following the wet milling and spray-drying processes. Size dependent in vitro dissolution profiles, utilizing a dialysis sac method were obtained for the crystalline powders.
Keywords: Nano-suspension; Spray drying; Re-dispersion; DoE; Nano-crystalline; Spray-dried powder;
Gastro-resistant characteristics of GRAS-grade enteric coatings for pharmaceutical and nutraceutical products by Justyna K. Czarnocka; Mohamed A. Alhnan (167-174).
Display OmittedThe use of naturally derived excipients to develop enteric coatings offers significant advantages over conventional synthetic polymers. Unlike synthetic polymers, they are biodegradable, relatively abundant, have no daily intake limits or restrictions on use for dietary and nutraceutical products. However, little information is available on their dissolution properties under different gastrointestinal conditions and in comparison to each other. This work investigated the gastric resistance properties of commercially available GRAS-based coating technologies. Three coating systems were evaluated: ethyl cellulose + carboxymethyl cellulose (EC-CMC), ethyl cellulose + sodium alginate (EC-Alg) and shellac + sodium alginate (Sh-Alg) combinations. The minimum coating levels were optimized to meet USP pharmacopoeial criteria for delayed release formulations (<10% release after 2 h in pH 1.2 followed by >80% release after 45 min of pH change). Theophylline 150 mg tablets were coated with 6.5%, 7%, and 2.75% coating levels of formulations EC-CMC, EC-Alg and Sh-Alg, respectively. In vitro dissolution test revealed a fast release in pH 6.8 for ethyl cellulose based coatings: t80% value of 65 and 45 min for EC-CMC and EC-Alg respectively, while a prolonged drug release from Sh-Alg coating was observed in both pH 6.8 and 7.4 phosphate buffers. However, when more biologically relevant bicarbonate buffer was used, all coatings showed slower drug release. Disintegration test, carried out in both simulated gastric and intestinal fluid, confirmed good mechanical resistance of EC-CMC and EC-Alg coating, and revealed poor durability of the thinner Sh-Alg. Under elevated gastric pH conditions (pH 2, 3 and 4), EC-CMC and EC-Alg coatings were broken after 70, 30, 55 min and after 30, 15, 15 min, respectively, while Sh-Alg coated tablets demonstrated gastric resistance at all pH values. In conclusion, none of the GRAS-grade coatings fully complied with the different biological demands of delayed release coating systems.
Keywords: Probiotics; Code oil; Delayed release; pH-dependent;
Preparation and characterization of azithromycin – Aerosil 200 solid dispersions with enhanced physical stability by Xuechao Li; Huanhuan Peng; Bin Tian; Jingxin Gou; Qing Yao; Xiaoguang Tao; Haibing He; Yu Zhang; Xing Tang; Cuifang Cai (175-184).
Display OmittedThe main purpose of this study was to investigate the feasibility of azithromycin (AZI) – Aerosil 200 solid dispersions specifically with high stability under accelerated condition (40 °C/75% RH). Ball milling (BM) and hot-melt extrusion (HME) were used to prepare AZI solid dispersions. The physical properties of solid dispersions were evaluated by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). For solid dispersions prepared with both methods, no crystalline of AZI was detected (except for AZI: Aerosil 200 = 75:25) by DSC or PXRD, indicating the amorphous state of AZI in solid dispersions. The FT-IR results demonstrated the loss of crystallization water and the formation of hydrogen bonds between Aerosil 200 and AZI during the preparation of solid dispersions. After 4 weeks storage under accelerated condition, the degree of crystallinity of AZI increased in solid dispersions prepared by BM, whereas for solid dispersions containing AZI, Aerosil 200 and glyceryl behenate (GB) prepared by HME, no crystalline of AZI was identified. This high stability can be attributed to the hydrophobic properties of GB and the presence of hydrogen bonds. Based on the above results, it is inferred the protection of hydrogen bonds between AZI and Aerosil 200 formed during preparation process effectively inhibited the recrystallization of AZI and improved the physical stability of amorphous AZI in the presence of Aerosil 200.
Keywords: Solid dispersion; Physical stability; Ball milling; Hot-melt extrusion; Aerosil 200;
Two solid forms of tauroursodeoxycholic acid and the effects of milling and storage temperature on solid-state transformations by Kailin Xu; Shoujun Zheng; Yuanming Zhai; Liuqi Guo; Peixiao Tang; Jin Yan; Di Wu; Hui Li (185-194).
Display OmittedTwo phase-pure solid forms of tauroursodeoxycholic acid (TUDCA) were prepared and characterized by thermal analysis, vibrational spectroscopy, X-ray diffraction, solid-state nuclear magnetic resonance, and morphological analysis. All solid forms can be produced from solvents and also can be obtained by mechanically and non-mechanically activated polymorph conversion. Near-infrared (NIR) spectroscopy, in combination with chemometrical techniques, was used for the quantitative monitoring of the polymorph conversion of TUDCA in milling process and at different storage temperatures. The NIR spectra in the range of 7139–5488 cm−1 were considered for multivariate analysis. Results demonstrated that the NIR multivariate chemometric model can predict the percentage of crystal and amorphous TUDCA with the correlation coeffcient of 0.9998, root mean square error of calibration of 0.740%, root mean square error of prediction of 0.698%, and root mean square error of cross-validation of 1.49%. In the milling process of crystal TUDCA (Form I), a direct transformation from crystal to glass was observed in 4 h. Moreover, the impact of different storage temperatures on the stability of amorphous TUDCA was investigated, and the rate of polymorph transformation was found to be accelerated with increasing temperature.
Keywords: Tauroursodeoxycholic acid; Polymorphism; Amorphous; Milling; Solid-state transformations;
Solid state formulations composed by amphiphilic polymers for delivery of proteins: characterization and stability by Fernanda Andrade; Pedro Fonte; Mireia Oliva; Mafalda Videira; Domingos Ferreira; Bruno Sarmento (195-206).
Development of powders obtained by lyophilization of polymeric micelles delivery of proteins. Micelles are easily recovered from the nanocomposites its after dispersion in water. The conformation of the protein is maintained at high percentages after lyophilization and up to 6 months when stored at both 4 °C and 20 °C.Display OmittedNanocomposite powders composed by polymeric micelles as vehicles for delivery proteins were developed in this work, using insulin as model protein. Results showed that size and polydispersity of micelles were dependent on the amphiphilic polymer used, being all lower than 300 nm, while all the formulations displayed spherical shape and surface charge close to neutrality. Percentages of association efficiency and loading capacity up to 94.15 ± 3.92 and 8.56 ± 0.36, respectively, were obtained. X-ray photoelectron spectroscopy (XPS) measurements confirmed that insulin was partially present at the hydrophilic shell of the micelles. Lyophilization did not significantly change the physical characteristics of micelles, further providing easily dispersion when in contact to aqueous medium. The native-like conformation of insulin was maintained at high percentages (around 80%) after lyophilization as indicated by Fourier transform infrared spectroscopy (FTIR) and far-UV circular dichroism (CD). Moreover, Raman spectroscopy did not evidenced significant interactions among the formulation components. The formulations shown to be physically stable upon storage up to 6 months both at room-temperature (20 °C) and fridge (4 °C), with only a slight loss (maximum of 15%) of the secondary structure of the protein. Among the polymers tested, Pluronic® F127 produced the carrier formulations more promising for delivery of proteins.
Keywords: Amphiphilic polymers; Insulin; Polymeric micelles; Lyophilization; Stability;
Preparation and characterization of micronized ellagic acid using antisolvent precipitation for oral delivery by Yong Li; Xiuhua Zhao; Yuangang Zu; Yin Zhang; Yunlong Ge; Chen Zhong; Weiwei Wu (207-216).
The miconized ellagic acid (m-EA) freeze-dried powder was obtained by antisolvent precipitation and lyophilization process. The m-EA freeze-dried powder exhibited higher antioxidant capacity and bioavailability than raw EA.Display OmittedIn this work, poorly water soluble phytochemical ellagic acid (EA) was micronized to increase its solubility and thereby the bioavailability during antisolvent precipitation process using N-methyl pyrrolidone (NMP) as solvent and deionized water as antisolvent. The micronized EA (m-EA) freeze-dried powder was prepared by the subsequent lyophilization process. The effects of various experimental parameters on the mean particle size (MPS) of m-EA suspension (m-EAS) in the antisolvent precipitation process were investigated. MPS and production efficiency were taken into account comprehensively to obtain the optimum conditions of antisolvent precipitation. Under the optimum conditions, m-EA freeze-dried powder with a MPS of 429.2 ± 7.6 nm was obtained. The physico-chemical properties of m-EA freeze-dried powder were detected by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), liquid chromatography–tandem mass spectrometry (LC–MS/MS), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results indicated m-EA kept the same chemical structure with raw EA, but the crystallinity was greatly reduced. Furthermore, a comparison of the 50% inhibition concentration (IC50) values revealed that m-EA was more effective than raw EA in scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. Meanwhile, m-EA also showed higher reducing power. Moreover, the residual amount of NMP was lower than the International Conference on Harmonization limit (530 ppm) for solvents. The dissolution rate of m-EA was approximately 2 times of raw EA. Moreover, the solubility of m-EA was about 6.5 times of raw EA. Meanwhile, the bioavailability of m-EA increased about 2 times compared with raw EA via oral administration.
Keywords: Ellagic acid; Antisolvent precipitation; Antioxidant activity; Dissolution rate; Bioavailability;
A slow-release system of bacterial cellulose gel and nanoparticles for hydrophobic active ingredients by Yukari Numata; Leticia Mazzarino; Redouane Borsali (217-225).
Display OmittedA combination of bacterial cellulose (BC) gel and amphiphilic block copolymer nanoparticles was investigated as a drug delivery system (DDS) for hydrophobic active ingredients. Poly(ethylene oxide)-b-poly(caprolactone) (PEO-b-PCL) and retinol were used as the block copolymer and hydrophobic active ingredient, respectively. The BC gel was capable of incorporating copolymer nanoparticles and releasing them in an acetic acid–sodium acetate buffer solution (pH 5.2) at 37 °C. The percentage of released copolymer reached a maximum value of approximately 60% after 6 h and remained constant after 24 h. The percentage of retinol released from the copolymer-containing BC gel reached a maximum value at 4 h. These results show that the combination of BC gel and nanoparticles is a slow-release system that may be useful in the cosmetic and biomedical fields for skin treatment and preparation.
Keywords: Bacterial cellulose gel; Nanoparticles; Block copolymer; Biocompatibility; Drug delivery system; Retinol;
Vancomycin-modified silica: Synthesis, controlled release and biological activity of the drug by Joanna Kurczewska; Paulina Sawicka; Magdalena Ratajczak; Marzena Gajęcka; Grzegorz Schroeder (226-231).
Display OmittedVancomycin was immobilized on three different organically functionalized silicas. The materials obtained were used for a controlled release of the antibiotic. The influence of the type of chemical bond on the in vitro drug release was investigated. A weak ionic bonding caused burst release of the drug within one day. A covalent bonding resulted in a slowdown in the release process and uniformity of dosage release. For these two carriers, biological activity of the drug was retained because the minimal inhibitory concentration values against the strains tested were similar to that of a free form of the drug (about 2 μg/mL). A strong ionic bonding of vancomycin adversely affected both the drug release, as well as its biological activity. A strong base on the surface of the silica prevented disconnection of the antibiotic which then became ineffective.
Keywords: Vancomycin; Silica; Covalent bonding; Ionic bonding; Controlled release; Biological activity;
Kinetically stable propofol emulsions with reduced free drug concentration for intravenous delivery by Robert Damitz; Anuj Chauhan (232-241).
Display OmittedIntravenous injections of propofol emulsions are accompanied by pain likely due to the interaction of the dissolved drug with endothelial cells of the vasculature. It is commonly hypothesized that reducing the aqueous phase concentration of propofol could reduce pain.To minimize the propofol concentration in the aqueous phase, we developed stable oil-in-water emulsions with excipient oil mixtures that have an increased partition coefficient for propofol. We then explored the emulsion stability by measuring size distributions after extended durations of shelf storage and also after freeze–thaw cycling. The effects of oil type, surfactant and salt concentration on emulsion stability were also explored.Small chain oils like ethyl butyrate exhibit high drug partitioning but poor stability, while larger molecules such as soybean oil exhibit lower partitioning but excellent emulsion stability. Emulsions with mixtures of soybean oil and ethyl butyrate are stable for longer than a year, resistant to freeze–thaw cycling, and reduce aqueous drug concentrations of propofol twofold compared to pure soybean oil emulsions.Oil-in-water emulsions of propofol formulated with mixtures of ethyl butyrate and soybean oil are kinetically stable and significantly reduce the aqueous phase drug concentration making them promising candidates for future propofol therapies.
Keywords: Propofol; Emulsion stability; Excipients; Partition coefficient; Surfactant; Interfacial phenomena;
Predicting the dissolution behavior of pharmaceutical tablets with NIR chemical imaging by Ketsia Yekpe; Nicolas Abatzoglou; Bernard Bataille; Ryan Gosselin; Tahmer Sharkawi; Jean-Sébastien Simard; Antoine Cournoyer (242-251).
Display OmittedNear infrared chemical imaging (NIRCI) is a common analytical non-destructive technique for the analysis of pharmaceutical tablets. This powerful process analytical technology provides opportunity to chemically understand the sample, and also to determine spatial distribution and size of ingredients in a tablet. NIRCI has been used to link disintegrant, excipients and active pharmaceutical ingredient (API) to tablet dissolution, as disintegrants play an important role in tablet disintegration, resulting in API dissolution. This article describes a specific methodology to predict API dissolution based on disintegrant chemical information obtained with NIRCI.First, several tablet batches with different disintegrant characteristics were produced. Then, NIRCI was successfully used to provide chemical images of pharmaceutical tablets. A PLS regression model successfully predicted dissolution profiles.These results show that NIRCI is a robust and versatile technique for measuring disintegrant properties in tablet formulations and predicting their effects on dissolution profiles. Thus, NIRCI could routinely complement and eventually replace dissolution testing by monitoring a critical material attribute: disintegrant content.
Keywords: Dissolution testing; Disintegrant; Near infrared chemical imaging; Quality by design; Multivariate data analysis; Kollidon CL;
Systematic identification of thermal degradation products of HPMCP during hot melt extrusion process by Hrushikesh Karandikar; Rohan Ambardekar; Adrian Kelly; Tim Gough; Anant Paradkar (252-258).
Display OmittedA systematic identification of the degradation products of hydroxypropyl methylcellulose phthalate (HPMCP) during hot melt extrusion (HME) has been performed. A reverse phase HPLC method was developed for the extrudates of both hydroxypropyl methylcellulose acetate succinate (HPMCAS) and HPMCP polymers to quantify their thermal hydrolytic products: acetic acid (AA), succinic acid (SA) for HPMCAS and phthalic acid (PA) for HPMCP, without hydrolysing the polymers in strong alkaline solutions. The polymers were extruded in the temperature range of 160–190 °C at different screw rotation speeds and hydrolytic impurities were analysed. Investigation of extruded HPMCP showed an additional thermal degradation product, who is structural elucidation revealed to be phthalic anhydride (PAH). Moreover, two environmental analytical impurities, dimethyl phthalate and methyl benzoate formed in situ were recorded on GC–MS and their origin was found to be associated with PAH derivatization. Using the experimental data gathered during this study, a degradation mechanism for HPMCP is proposed.
Keywords: HME; HPMCAS; HPMCP; Thermal degradation; Degradation products and mechanism;
Curcumin delivery from poly(acrylic acid-co-methyl methacrylate) hollow microparticles prevents dopamine-induced toxicity in rat brain synaptosomes by Krassimira Yoncheva; Magdalena Kondeva-Burdina; Virginia Tzankova; Petar Petrov; Mohamed Laouani; Silvia S. Halacheva (259-267).
Display OmittedThe potential of poly(methyl methacrylate-co-acrylic acid) (PMMA-AA) copolymers to form hollow particles and their further formulation as curcumin delivery system have been explored. The particles were functionalized by crosslinking the acrylic acid groups via bis-amide formation with either cystamine (CYS) or 3,3′-dithiodipropionic acid dihydrazide (DTP) which simultaneously incorporated reversibility due to the presence of disulfide bonds within the crosslinker. Optical micrographs showed the formation of spherical hollow microparticles with a size ranging from 1 to 7 μm. Curcumin was loaded by incubation of its ethanol solution with aqueous dispersions of the cross-linked particles and subsequent evaporation of the ethanol. Higher loading was observed in the microparticles with higher content of hydrophobic PMMA units indicating its influence upon the loading of hydrophobic molecules such as curcumin. The in vitro release studies in a phosphate buffer showed no initial burst effect and sustained release of curcumin that correlated with the swelling of the particles under these conditions. The capacity of encapsulated and free curcumin to protect rat brain synaptosomes against dopamine-induced neurotoxicity was examined. The encapsulated curcumin showed greater protective effects in rat brain synaptosomes as measured by synaptosomal viability and increased intracellular levels of glutathione.
Keywords: Hollow microspheres; Poly(methyl methacrylate-co-acrylic acid); Disulphide crosslinking; Curcumin; Rat brain synaptosomes;
Downstream processing of polymer-based amorphous solid dispersions to generate tablet formulations by B. Démuth; Z.K. Nagy; A. Balogh; T. Vigh; G. Marosi; G. Verreck; I. Van Assche; M.E. Brewster (268-286).
Display OmittedApplication of amorphous solid dispersions (ASDs) is considered one of the most promising approaches to increase the dissolution rate and extent of bioavailability of poorly water soluble drugs. Such intervention is often required for new drug candidates in that enablement, bioavailability is not sufficient to generate a useful product. Importantly, tableting of ASDs is often complicated by a number of pharmaceutical and technological challenges including poor flowability and compressibility of the powders, compression-induced phase changes or phase separation and slow disintegration due to the formation of a gelling polymer network (GPN). The design principles of an ASD-based system include its ability to generate supersaturated systems of the drug of interest during dissolution. These metastable solutions can be prone to precipitation and crystallization reducing the biopharmaceutical performance of the dosage form. The main aim of the research in this area is to maintain the supersaturated state and optimally enhance bioavailability, meaning that crystallization should be delayed or inhibited during dissolution, as well as in solid phase (e.g., during manufacturing and storage). Based on the expanding use of ASD technology as well as their downstream processing, there is an acute need to summarize the results achieved to this point to better understand progress and future risks. The aim of this review is to focus on the conversion of ASDs into tablets highlighting results from various viewpoints.
Keywords: Amorphous solid dispersion; Tableting; Gelling polymer network; Electrospinning; Extrusion; Spray-drying;
Adenosine conjugated lipidic nanoparticles for enhanced tumor targeting by Rajan Swami; Indu Singh; Manish Kumar Jeengar; V.G.M. Naidu; Wahid Khan; Ramakrishna Sistla (287-296).
Display OmittedDelivering chemotherapeutics by nanoparticles into tumor is impeded majorly by two factors: nonspecific targeting and inefficient penetration. Targeted delivery of anti-cancer agents solely to tumor cells introduces a smart strategy because it enhances the therapeutic index compared with untargeted drugs. The present study was performed to investigate the efficiency of adenosine (ADN) to target solid lipid nanoparticles (SLN) to over expressing adenosine receptor cell lines such as human breast cancer and prostate cancer (MCF-7 and DU-145 cells), respectively. SLN were prepared by emulsification and solvent evaporation process using docetaxel (DTX) as drug and were characterized by various techniques like dynamic light scattering, differential scanning calorimeter and transmission electron microscopy. DTX loaded SLNs were surface modified with ADN, an adenosine receptors ligand using carbodiimide coupling. Conjugation was confirmed using infrared spectroscopy and quantified using phenol–sulfuric acid method. Conjugated SLN were shown to have sustained drug release as compared to unconjugated nanoparticles and drug suspension. Compared with free DTX and unconjugated SLN, ADN conjugated SLN showed significantly higher cytotoxicity of loaded DTX, as evidenced by in vitro cell experiments. The IC50 was 0.41 μg/ml for native DTX, 0.30 μg/ml for unconjugated SLN formulation, and 0.09 μg/ml for ADN conjugated SLN formulation in MCF-7 cell lines. Whereas, in DU-145, there was 2 fold change in IC50 of ADN–SLN as compared to DTX. IC50 was found to be 0.44 μg/ml for free DTX, 0.39 μg/ml for unconjugated SLN and 0.22 μg/ml for ADN–SLN. Annexin assay and cell cycle analysis assay further substantiated the cell cytotoxicity. Fluorescent cell uptake and competitive ligand-receptor binding assay corroborated the receptor mediated endocytosis pathway indicated role of adenosine receptors in internalization of conjugated particles. Pharmacokinetic studies of lipidic formulations depicted significant improvement in pharmacokinetic parameters than marketed formulation. ADN conjugated SLN proved to be an efficient drug delivery vehicle. Hence, ADN can be used as a potential ligand to target breast and prostate cancer.
Keywords: Adenosine; Adenosine receptors; Solid lipid nanoparticles; Conjugation; Cell cycle analysis;
Development of gastroretentive metronidazole floating raft system for targeting Helicobacter pylori by Nancy Abdel Hamid Abou Youssef; Abeer Ahmed Kassem; Magda Abd Elsamea EL-Massik; Nabila Ahmed Boraie (297-305).
Display OmittedThe study demonstrates the feasibility of prolonging gastric residence time and release rate of metronidazole (Mz) by preparing floating raft system (FRS) using ion-sensitive in situ gel forming polymers. FRSs contained 3, 4, 5 and 0.5, 0.75, 1% w/v sodium alginate (Alg) and gellan gum (G), respectively, 0.25% w/v sodium citrate and calcium carbonate (C). Lipids: glyceryl mono stearate (GMS), Precirol® and Compritol® were incorporated into G-based formulations (G1%C1%). Mz:lipid ratio was 1:1, except for Mz:GMS, ratios of 1:1.5 and 1:2 were also investigated. Buoyancy, gelation capacity and viscosity parameters were evaluated. Drug release and kinetics for selected formulae were examined. The selected lipid containing formula was subjected to an accelerated stability testing.Alg4%C2% FRS exhibited short gelation lag time (3 s), long duration (>24 h), floating lag time 1 min and duration >24 h, and a reliable sustained drug release (MDT 6 h). Gellan gum FRSs achieved successful floating gastroretention, but failed to achieve the required gelation capacity. Incorporation of GMS (Mz:GMS 1:1) enhanced the gelation lag time and duration (6 s and >24 h, respectively), keeping sustained drug release and formulation stability. The improved characteristics of the selected FRS make them excellent candidates for gastric targeting to eradicate Helicobacter pylori.
Keywords: Sodium alginate; Gellan gum; Glyceryl mono stearate; Precirol®; Compritol®; Gelation capacity;
Amorphous solid dispersions of piroxicam and Soluplus®: Qualitative and quantitative analysis of piroxicam recrystallization during storage by Andres Lust; Clare J. Strachan; Peep Veski; Jaakko Aaltonen; Jyrki Heinämäki; Jouko Yliruusi; Karin Kogermann (306-314).
Display OmittedThe conversion of active pharmaceutical ingredient (API) from amorphous to crystalline form is the primary stability issue in formulating amorphous solid dispersions (SDs). The aim of the present study was to carry out qualitative and quantitative analysis of the physical solid-state stability of the SDs of poorly water-soluble piroxicam (PRX) and polyvinyl caprolactam-polyvinyl acetate-polyethylene-glycol graft copolymer (Soluplus®). The SDs were prepared by a solvent evaporation method and stored for six months at 0% RH/6 °C, 0% RH/25 °C, 40% RH/25 °C and 75% RH/25 °C. Fourier transform infrared spectroscopy equipped with attenuated total reflection accessory (ATR-FTIR) and Raman spectroscopy were used for characterizing the physical solid-state changes and drug–polymer interactions. The principal component analysis (PCA) and multivariate curve resolution alternating least squares (MCR-ALS) were used for the qualitative and quantitative analysis of Raman spectra collected during storage. When stored at 0% RH/6 °C and at 0% RH/25 °C, PRX in SDs remained in an amorphous form since no recrystallization was observed by ATR-FTIR and Raman spectroscopy. Raman spectroscopy coupled with PCA and MCR-ALS and ATR-FTIR spectroscopy enabled to detect the recrystallization of amorphous PRX in the samples stored at higher humidity.
Keywords: Amorphous solid dispersion; Physical stability; Dissolution; Piroxicam; Soluplus®; Vibrational spectroscopy; Multivariate curve resolution; Principal component analysis;
Tablet mechanics depend on nano and micro scale adhesion, lubrication and structure by Maria Badal Tejedor; Niklas Nordgren; Michael Schuleit; Mark W. Rutland; Anna Millqvist-Fureby (315-323).
Display OmittedTablets are the most convenient form for drug administration. However, despite the ease of manufacturing problems such as powder adhesion occur during the production process. This study presents surface and structural characterization of tablets formulated with commonly used excipients (microcrystalline cellulose (MCC), lactose, mannitol, magnesium (Mg) stearate) pressed under different compaction conditions. Tablet surface analyses were performed with scanning electron microscopy (SEM), profilometry and atomic force microscopy (AFM). The mechanical properties of the tablets were evaluated with a tablet hardness test. Local adhesion detected by AFM decreased when Mg stearate was present in the formulation. Moreover, the tablet strength of plastically deformable excipients such as MCC was significantly decreased after addition of Mg stearate. Combined these facts indicate that Mg stearate affects the particle–particle bonding and thus elastic recovery. The MCC excipient also displayed the highest hardness which is characteristic for a highly cohesive material. This is discussed in the view of the relatively high adhesion found between MCC and a hydrophilic probe at the nanoscale using AFM. In contrast, the tablet strength of brittle materials like lactose and mannitol is unaffected by Mg stearate. Thus fracture occurs within the excipient particles and not at particle boundaries, creating new surfaces not previously exposed to Mg stearate. Such uncoated surfaces may well promote adhesive interactions with tools during manufacture.
Keywords: Tableting; Excipients; Adhesion; Atomic force microscopy; Profilometry; Surface roughness;
Nanomechanical testing technique for millimeter-sized and smaller molecular crystals by Michael R. Maughan; M. Teresa Carvajal; David F. Bahr (324-330).
Display OmittedLarge crystals are used as a control for the development of a mounting and nanoindentation testing technique for millimeter-sized and smaller molecular crystals. Indentation techniques causing either only elastic or elastic–plastic deformation produce similar results in assessing elastic modulus, however, the elastic indents are susceptible to surface angle and roughness effects necessitating larger sample sizes for similar confidence bounds. Elastic–plastic indentations give the most accurate results and could be used to determine the different elastic constants for anisotropic materials by indenting different crystal faces, but not by rotating the indenter about its axis and indenting the same face in a different location. The hardness of small and large crystals is similar, suggesting that defect content probed in this study is similar, and that small crystals can be compared directly to larger ones. The Young’s modulus and hardness of the model test material, griseofulvin, are given for the first time to be 11.5 GPa and 0.4 GPa respectively.
Keywords: Griseofulvin; Nanoindentation; Molecular crystals; Elastic–plastic indentation; Batch variation;
Dehydration mechanism of caffeine hydrate and structural description of driven metastable anhydrates analyzed by micro Raman spectroscopy by Alain Hédoux; Laurent Paccou; Patrick Derollez; Yannick Guinet (331-338).
Display OmittedThis study shows the contribution of Raman spectroscopy to carefully describe the mechanism of solid-state transformation at the molecular level, by simultaneously monitoring the molecular reorganization and the water escape during the dehydration kinetics. Dehydration of monohydrate caffeine was analyzed at various temperatures. In-situ low- and high-frequency Raman investigations provide information on the long-range and local arrangement of caffeine molecules, during the dehydration kinetics and in the anhydrate state. The nature of the anhydrate was determined, from the analysis in the low-frequency region, as metastable and transient between both polymorphic forms of anhydrous caffeine. It was shown that changing the temperature mainly induces structural reorganization of caffeine molecules in the hydrate state, leading to an anhydrate more or less transformed in form I of anhydrous caffeine.
Keywords: Raman spectroscopy; Dehydration; Solid-state transformation; Caffeine;
A miniaturized in vitro release method for investigating drug-release mechanisms by E. Ahnfelt; E. Sjögren; N. Axén; H. Lennernäs (339-349).
Display OmittedWe have evaluated a miniaturized in vitro method, based on the μDISS Profiler™ technique that enables on-line monitoring of drug release from a 21 μl sample with 10 ml of release medium. Four model drugs in eight clinically used formulations, including both solid and non-solid drug delivery systems, were investigated. The acquired data were compared with historical in vitro release data from the same formulations. Use of the Weibull function to describe the in vitro drug-release profiles allowed discrimination between the selected formulations with respect to the drug-release mechanisms. Comparison of the release data from the same formulation in different in vitro set-ups showed that the methodology used can affect the mechanism of in vitro release. We also evaluated the ability of the in vitro methods to predict in vivo activity by comparing simulated plasma concentration-time profiles acquired from the application of the biopharmaceutical software GI-Sim to the in vitro observations. In summary, the simulations based on the miniaturized-method release data predicted the plasma profiles as well as or more accurately than simulations based on the historical release data in 71% of the cases and this miniaturized in vitro method appears to be applicable for both solid and non-solid formulations.
Keywords: In vitro release methods; Release mechanisms; Weibull function; GI-Sim; In vivo prediction;
Semi-solid fluorinated-DPPC liposomes: Morphological, rheological and thermic properties as well as examination of the influence of a model drug on their skin permeation by Denise-Silvia Mahrhauser; Gottfried Reznicek; Harald Kotisch; Marlene Brandstetter; Corinna Nagelreiter; Kristina Kwizda; Claudia Valenta (350-355).
Display OmittedThe goal of this study was to investigate the influence of an incorporated model drug on the skin permeation of the vehicle itself as it may affect the microstructure and properties of the applied formulation via molecular interactions. For this purpose, we performed skin permeation studies using liposomes prepared with F-DPPC, a monofluorinated analog of dipalmitoylphosphatidylcholine (DPPC), with and without sodium fluorescein (SoFl) serving as model drug. Interestingly, the liposome preparation with F-DPPC yielded semi-solid opalescent systems. Hence, a thorough characterization was accomplished beforehand by electron microscopy imaging, rheological and thermoanalytical experiments. Freeze-fracture electron microscopy images confirmed the existence of globular shaped vesicles in the F-DPPC preparations and oscillatory rheological measurements proved the viscoelastic properties of F-DPPC and F-DPPC+SoFl liposomes in contrast to the viscous characteristics of DPPC liposomes. Thermoanalytical measurements revealed an increased phase transition temperature T m of about 50 °C for F-DPPC and F-DPPC+SoFl liposomes compared to pure DPPC liposomes with a T m of about 43 °C. The similar T m of F-DPPC+SoFl and F-DPPC liposomes as well as the similar skin permeation of the vehicle compound F-DPPC compared to its drug-free counterpart suggest an incorporation of sodium fluorescein into the aqueous core of F-DPPC liposomes.
Keywords: F-DPPC; Fluorescein sodium salt; Freeze fracture; Mass spectrometry; Skin permeation;
In vitro and in vivo evaluation of APRPG-modified angiogenic vessel targeting micelles for anticancer therapy by Pan Guo; Shuangshuang Song; Zhao Li; Ye Tian; Jiatong Zheng; Xinggang Yang; Weisan Pan (356-366).
Display OmittedThe study was aimed to evaluate the antitumor potential of the Ala-Pro-Arg-Pro-Gly (APRPG)-modified angiogenic vessel targeting drug delivery system using paclitaxel (PTX) as a model drug.In this study, an angiogenesis homing peptide APRPG was conjugated to the amphipathic copolymer PLGA–PEG and the synthesized copolymer APRPG–PEG–PLGA was used to prepare PTX encapsulated micelles (APRPG–PEG-Mic). The micelles were uniform spherical and exhibited a unimodal particle size distribution and a slight negative zeta-potential. The in vitro drug release result demonstrated a significant sustained release property of APRPG–PEG-Mic. Compared to Taxol® and Cont-PEG-Mic, APRPG–PEG-Mic showed a stronger cytotoxicity against two cancerous cell lines. In the cell uptake studies, the APRPG-modified micelles enhanced intracellular fluorescent intensity in EA.hy926 cells. The biodistribution study revealed the accumulation of APRPG–PEG-Mic in tumor tissues as a result of passive accumulation and active targeting. In comparison with Taxol® and Cont-PEG-Mic, APRPG–PEG-Mic reduced the tumor volume more significantly and prolonged the survival time of tumor-bearing mice, indicating a higher antitumor efficacy and lower systematic side effects of APRPG–PEG-Mic.The results indicated that APRPG-modified micelles could be an efficient target-delivery method to angiogenic vessels and a highly promising therapeutic system in anticancer therapy.
Keywords: Anticancer therapy; Paclitaxel; Angiogenic vessel targeting; Micelle; Long circulation; Tumor targeting;
Stability of colistimethate sodium in a disposable elastomeric infusion device by Alan Abdulla; Roelof W.F. van Leeuwen; Aurelia H.M. de Vries Schultink; Birgit C.P. Koch (367-369).
Display OmittedInfections of the respiratory tract with Pseudomonas aeruginosa in cystic fibrosis patients are frequently treated with colistimethate sodium (CMS). For the intravenous administration of CMS a disposable elastomeric pump is a convenient option. To date, there are no data available on the chemical stability of CMS solutions stored in elastomeric pumps. We evaluated the chemical stability of 0.8 mg/mL solutions of CMS by measuring the degradation over a period of 7 days. Test samples were prepared by diluting CMS with saline solution (0.9%). The preparations were transferred to 100-mL elastomeric pumps and stored at 4 °C. The chemical stability was measured by a high-performance liquid chromatography method with UV detection. There was no degradation of CMS (<0.5% of CMS present as colistin) for at least 3 day at 4 °C, and after 7 days all test samples remained chemically stable (<5% of CMS present as colistin). Since colistin formed in pharmacy-compounded CMS solutions prior to administration may cause toxicity, we advise that the solution should be used before the hydrolysis of CMS occurs. Therefore, we recommend that the 0.8 mg/mL solution of CMS can be stored for up to 3 days at 4 °C in an elastomeric pump.
Keywords: Colistin; Colistimethate sodium; Elastomeric pump; Stability;
Novel coprocessed excipients composed of lactose, HPMC, and PVPP for tableting and its application by SongTao Wang; JinZhi Li; Xiao Lin; Yi Feng; Xiang Kou; Sreehari Babu; Riccardo Panicucci (370-379).
Display OmittedNew coprocessed excipients composed of α-lactose monohydrate (a filler), HPMC E3 (a binder), and PVPP (a superdisintegrant) were developed by spray drying in this study to improve the tableting properties of lactose. Factors affecting the properties of the coprocessed excipients were investigated by a 3 × 3× 2 factorial design. These factors include lactose grade (90 M, 200 M, and 450 M), percentage of HPMC (3.5%, 7.0%, and 10.5%), and percentage of PVPP (0% and 3.5%). The results show that the compactability of the excipients could be significantly improved by increasing either the percentage of HPMC or the primary particle size of lactose. The addition of 3.5% PVPP had little effect on the compactability, but significantly improved the disintegration ability. The developed coprocessed excipients have much lower yield pressures and much higher working efficiency during tableting compared to the main raw material (α-lactose monohydrate). These improvements are mainly attributed to the addition of HPMC and the proximately 30% amorphous lactose formed during process. Both HPMC and amorphous lactose were homogeneously distributed on the surface of the secondary particles, maximizing their effect. Furthermore, the low hygroscopicity and high glass transition temperature of HPMC led to a high yield. The drug loading capacity of the newly coprocessed excipients is also excellent. In summary, the tri-component coprocessed excipients investigated are promising and worthy of further development.
Keywords: Lactose; HPMC; Spray drying; Compactability; Coprocessed excipients;
Core–shell structured Fe3O4@TiO2-doxorubicin nanoparticles for targeted chemo-sonodynamic therapy of cancer by Song Shen; Lin Wu; Jiejie Liu; Meng Xie; Haijun Shen; Xueyong Qi; Yongmin Yan; Yanru Ge; Yi Jin (380-388).
Display OmittedTo facilitate targeting drug delivery and combined therapy, we develop titanium dioxide-encapsulated Fe3O4 nanoparticles (Fe3O4@TiO2 NPs). Titanium dioxide (TiO2), which is employed as a sonosensitizer for sonodynamic therapy (SDT), can also be used for the loading of doxorubicin (DOX). The fabricated Fe3O4@TiO2 NPs exhibit pH-dependent loading and release of doxorubicin (DOX) in vitro. After incubation with cancer cells, reactive oxygen species (ROS) are generated efficiently upon the irradiation of ultrasound. In the biodistribution experiments, extremely high in vivo tumor accumulation of Fe3O4@TiO2 NPs and long-time retention effect are observed. Compared with chemotherapy or sonodynamic treatment alone, the combined therapy demonstrated a synergistic effect, resulting in stronger cytotoxicity and higher therapeutic efficacy. Thus, the constructed NPs are endowed with multifunctions which allow them to selectively deliver combinatorial therapeutic payload to tumor with enhanced therapeutic effectiveness and minimal side effects.
Keywords: Sonodynamic therapy; Magnetic iron oxide; Tumor targeting; Doxorubicin; Combined therapy;