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Background: Hydrophilic Hydroxypropyl Methylcellulose (HPMC) matrix tablets are the standard role model of the oral controlled-release formulation. Nevertheless, the HPMC kinetics for the mechanistic understanding of drug release and hydrodynamic behaviors are rarely investigated. This study aims to investigate the release behaviors of both HPMC and paracetamol (model drug) from the hydrophilic matrix tablet. Methods: Two different viscosity grades of HPMC were used (Low viscosity: 6 cps, High viscosity: 4,000 cps). Three different ratios of drug/HPMC (H:38.08%, M:22.85%, and L:15.23% (w/w) of HPMC amounts in total weight) matrix tablets were prepared by wet granulation technique. The release profiles of the drug and HPMC in a matrix tablet were quantitatively analyzed by HPLC and 1H-Nuclear Magnetic Resonance (NMR) spectroscopy. The hydrodynamic changes of HPMC were determined by the gravimetric behaviors such as swelling and erosion rates, gel layer thickness, front movement data,and distributive Near-Infrared (NIR) chemical imaging of HPMC in a matrix tablet during the dissolution process. Results: High viscosity HPMC tablets showed slower release of HPMC than the release rate of drug, suggesting that drug release preceded polymer release.Different hydration phenomenon was qualitatively identified and corresponded to the release profiles. The release behaviors of HPMC and drug in the tablet could be distinguished with the significant difference with fitted dissolution kinetics model (Low viscosity HPMC 6cps; Korsmeyer-Peppas model, High viscosity HPMC 4000cps; Hopfenberg model, Paracetamol; Weibull model) according to the weight of ingredients and types of HPMC. Conclusion: The determination of HPMC polymer release correlating with drug release, hydrodynamic behavior, and NIR chemical imaging of HPMC can provide new insights into the drug release- modulating mechanism in the hydrophilic matrix system.

Background: This study aimed to evaluate the effects of hydrophobic and hydrophilic Film-Forming Gels (FFGs) on the controlled delivery of drugs with different levels of hydrophobicity. Methods: This evaluation was carried out by employing zein and polyvinylpyrrolidone as hydrophobic and hydrophilic film-forming agents, respectively, in combination with hydroxypropyl methylcellulose functionalized as a hydrogel basement at a ratio that had been optimized to achieve the fastest drying time. Free curcumin or terbinafine hydrochloride was subsequently dispersed into blank FFGs to produce the final FFG formulations. Results: Although the extreme hydrophobicity of curcumin strongly limited its topical permeability compared to that of terbinafine hydrochloride, zein FFGs clearly resulted in a favourable sustained release system for highly hydrophobic drugs, such as curcumin. Moreover, polyvinylpyrrolidone would be highly effective for the sustained release of a less hydrophobic drug, such as terbinafine hydrochloride. Analyses of the wettability, surface morphology, chemical interactions and crystallinity of FFGs also helped to elucidate the mechanisms of their drug release profiles. Conclusion: This fundamental finding is beneficial for further design studies on FFGs as sustained drug delivery systems for topical drugs with a wide range of hydrophobicities.

Industrial-scale pharmaceutical applications still face many challenges in overcoming the low absorption and bioavailability of poorly water-soluble drugs. Hot-melt extrusion has emerged as a promising approach with continuous processing on an industrial scale for the preparation of drug delivery systems. Many reviews have mentioned the potential applications, processes, principles and advantages and disadvantages of hot-melt extrusion in the pharmaceutical industry. However, a focus on the recent progress of hot-melt extrusion, which investigates the impacts of processes and formulations of solid dispersions of poorly water-soluble drugs, is missing. In this review, various factors, including polymers, drug properties, additives and surfactants, in solid dispersion SD formulations by hot-melt extrusion will be discussed. Moreover, the effects of the hot-melt extrusion process on the physicochemical properties of solid dispersions will be mentioned. The utilization of molecular interactions in hot-melt extrusion to improve drug stability will also be described. Overall, this summary of recent studies on solid dispersion by hot-melt extrusion will provide perspectives and effectiveness for the development of formulations containing poorly water-soluble drugs.

Aspirin has emerged as a promising intervention in cancer in the past decade. However, there are existing controversies regarding the anticancer properties of aspirin as its mechanism of action has not been clearly defined. In addition, the risk of bleeding in the gastrointestinal tract from aspirin is another consideration that requires medical and pharmaceutical scientists to work together to develop more potent and safe aspirin therapy in cancer. This review presents the most recent studies of aspirin with regard to its role in cancer prevention and treatment demonstrated by highlighted clinical trials, mechanisms of action as well as approaches to develop aspirin therapy best beneficial to cancer patients. Hence, this review provides readers with an overview of aspirin research in cancer that covers not only the unique features of aspirin, which differentiate aspirin from other non-steroidal anti-inflammatory drugs (NSAIDs), but also strategies that can be used in the development of drug delivery systems carrying aspirin for cancer management. These studies convey optimistic messages on the continuing efforts of the scientist on the way of developing an effective therapy for patients with a low response to current cancer treatments.

A new pH-responsive cationic co-liposomal formulation was prepared in this study using the twin version of the amphiphile palmitoyl homocysteine, TPHC; natural zwitterionic lipid, DOPE; and cholesterol-based twin cationic lipid, C5C, at specified molar ratios. This co-liposome was further decorated with a newly designed fluorescently tagged, cholesterol-tethered EpCAM-targeting RNA aptamer for targeted gene delivery. This aptamer-guided nanoliposomal formulation, C5C/DOPE/TPHC at 8:24:1 molar ratio, could efficiently transport the genes in response to low pH of cellular endosomes selectively to the EpCAM overexpressing cancer stem cells. This particular observation was extended using siRNA against GFP to validate their transfection capabilities in response to EpCAM expression. Overall, the aptamer-guided nanoliposomal formulation was found to be an excellent transfectant for in vitro siRNA gene delivery.

Yongjun Yu,1 Hai V Ngo,1 Gang Jin,1 Phuong HL Tran,2 Thao TD Tran,3,4 Van Hong Nguyen,5 Chulhun Park,6 Beom-Jin Lee1 1College of Pharmacy, Ajou University, Suwon, 16499, Republic of Korea; 2Deakin University, School of Medicine, Geelong, Australia; 3Institute of Research and Development, Duy Tan University, Danang, 550000, Vietnam; 4The Faculty of Pharmacy, Duy Tan University, Danang, 550000, Vietnam; 5Pharmaceutical Engineering Laboratory, Biomedical Engineering Department, International University, Vietnam National University, Ho Chi Minh City, 70000, Vietnam; 6Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, CanadaCorrespondence: Beom-Jin LeeBioavailability Control Laboratory, College of Pharmacy, Ajou University, Suwon, 16499, Republic of KoreaTel +82312193442Fax +82312193435Email bjl@ajou.ac.krPurpose: To investigate the effects of solvents on the formation of self-assembled nanonization of albumin-oleic acid conjugates (AOCs) using a solvent exchange mechanism for the construction of in situ forming implants (ISFI).Methods: A poorly water-soluble drug, paliperidone palmitate (PPP), was chosen as the model drug. AOC was synthesized with the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) reaction. Dichloromethane, tetrahydrofuran, ethanol, N-methyl-2-pyrrolidone, dimethyl sulfoxide, and deionized water were selected to investigate the formation of self-assembled AOC nanoparticles (AONs). The volume ratios of organic solvents against water could determine the miscibility, injectability, and in situ nanonizing capability without aggregation.Results: As the polarity of the organic solvents increased, the AONs exhibited a spherical shape, and the larger the volume of the solvent, the smaller the size of the AONs. To use AOC in ISFI for controlled release of PPP, poly(d,l-lactide-co-glycolide) (PLGA) was combined with the AOC in 2 mL of N-methyl-2-pyrrolidone and water solution (1.8/0.2 ratio). The release rates of all formulations exhibited similar curve patterns overall but were more controlled in decreasing order as follows: AOC, PLGA, and AOC/PLGA for 14 days.Conclusion: A combined formulation of AOC and PLGA was found to effectively control the initial burst release of the drug.Keywords: albumin-oleic acid conjugate, self-assembled nanonization, solvent type, in situ forming implant, solvent exchange, controlled release

Solid dispersions offer many advantages for oral drug delivery of poorly water-soluble drugs over other systems, including an increase in drug solubility and drug dissolution. An improvement in drug absorption and the higher bioavailability of active pharmaceutical ingredients in the gastrointestinal tract have been reported in various studies. In certain circumstances, a rapid pharmacological effect is required for patients. Fastdissolving solid dispersions provide an ideal formulation in such cases. This report will provide an overview of current studies on fast-dissolving solid dispersions, including not only solid dispersion powders with fast dissolution rates but also specific dose form for the controlled release of poorly water-soluble drugs. Specifically, the applications of fast-dissolving solid dispersions will be described in every specific case. Moreover, pharmaceutical approaches and the utilization of polymers will be summarized. The classification and analysis of fastdissolving solid dispersions could provide insight into strategies and potential applications in future drug delivery developments.

Mucoadhesive formulations have been demonstrated to result in efficient drug delivery systems with advantages over existing systems such as increased local retention and sustained drug release via adhesiveness to mucosal tissues. The controlled release of colon-targeted, orally administered drugs has recently attracted a number of studies investigating mucoadhesive systems. Consequently, substantial designs, from mucoadhesive cores to shells of particles, have been studied with promising applications. This review will provide an overview of specific strategies for developing mucoadhesive systems for colon-targeted oral delivery with controlled drug release, including mucoadhesive matrices, cross-linked mucoadhesive microparticles, coatings and mucoadhesive nanoparticles. The understanding of the basic principle of these designs and advanced formulations throughout will lead to the development of products with efficient drug delivery at the colon for therapies for different diseases.

Aims: The purpose of this study was to investigate and compare the formation of polymeric and Ocimum gratissimum seed films containing solid lipid particles for controlled drug release. Methods: The hot homogeneous method was selected to form solid lipid particles containing sodium fusidate to load the drug into the film. The in vitro drug release and drug permeability of the films were tested with dialysis tubes and the Franz diffusion cell method, respectively. The mucoadhesive time and swelling and erosion rates were also studied. Results: The solid lipid particles showed the ability to form Ocimum gratissimum seed and polymeric films for use in drug delivery. Although the polymeric matrix yielded excellent swelling and erosion rates, leading to a faster drug release rate and drug permeation than that of the Ocimum gratissimum seed film, the mucoadhesive time of the polymer film was worse than that of the seed film. Conclusion: Therefore, the characteristics of the individual systems may be further studied in a combined system to take full advantage of both in the desired film.

It has been well established that solid dispersions have a high potential to increase the release rate of poorly water-soluble drugs, resulting in high drug bioavailability. Solid dispersions have been vigorously investigated with various practical approaches in recent decades. Improvements in wettability, molecular interactions and drugs being held in an amorphous state in solid dispersions are the main mechanisms underlying the high drug release rate. Moreover, the synergistic effect of incorporating nanotechnology in solid dispersions is expected to lead to an advanced drug delivery system for poorly water-soluble drugs. However, to date, there is still a lack of reviews providing outlooks on the nano-sized solid dispersions that have been substantially investigated for improving the bioavailability of poorly water-soluble drugs. In the current review, we aim to overview key advantages and approaches for producing nano-sized solid dispersions. The classification of key strategies in developing nano-sized solid dispersions will advance the creation of even more efficient solid dispersions, which will translate into clinical studies.

Background: Natural materials have been encouraged in controlled drug release and improved drug bioavailability. Objective: This study aimed to develop a modification process for the use of a natural material, Ocimum gratissimum seeds (OGS), in Orally Disintegrating Tablets (ODTs). Methods: The OGS was investigated with four different modification processes including only milling, swelling, swelling/milling, and swelling/milling/incubation. The ODTs containing the modified OGS as a disintegrant were prepared by the wet granulation method. Furthermore, an evaluation to assess parameters of tablets, such as weight variation, hardness, friability, wetting time, disintegration time, drug content, and dissolution studies, was performed. Results: The modification of OGS using the swelling/ milling process resulted in a completion of OGS modification, leading to an ideal wetting time, disintegrating time, and dissolution rate. The OGS concentrations also affected the wetting and disintegrating time with the optimal range of ODTs from 15% to 20%. On the other hand, the modification with the incubation processes varied by temperature and time increased the wetting time and disintegrating time. Conclusions: The modified OGS demonstrated that it is a potential material with the advantages of cost-effectiveness, non-toxicity and easy manufacture in the preparation of ODTs.

Extracellular vesicles have an excellent ability to transfer their contents to cells. Extracellular vesicles can also be engineered to deliver therapeutic molecules to target cells. Although a number of studies have exploited synthesized nanoparticles in the treatment of neurological disease in the past few years, extracellular vesicles have been investigated and shown tremendous promise for clinical applications because they are safe and have strong targeting specificity. Different types of extracellular vesicles have been studied and modified for delivering therapeutic factors in neurological disease, including extracellular vesicles loaded with natural therapeutic factors and therapeutic molecules. In this review, we discuss delivery systems using extracellular vesicles containing molecules of interest and then focus on main strategies used for EV loading and surface modification. Discussing these important issues will support and facilitate the design and development of promising techniques and products for neurological therapy.

Improving drug bioavailability in the pharmaceutical field is a challenge that has attracted substantial interest worldwide. The controlled release of a drug can be achieved with a variety of strategies and novel materials in the field. In addition to the vast development of innovative materials for improving therapeutic effects and reducing side effects, the exploration of remarkable existing materials could encourage the discovery of diverse approaches for adapted drug delivery systems. Recently, superdisintegrants have been proposed for drug delivery systems as alternative approaches to maximize the efficiency of therapy. Although superdisintegrants are well known and used in solid dosage forms, studies on strategies for the development of drug delivery systems using superdisintegrants are lacking. Therefore, this study reviews the use of superdisintegrants in controlled drug release dosage formulations. This overview of superdisintegrants covers developed strategies, types (including synthetic and natural materials), dosage forms and techniques and will help to improve drug delivery systems.

Exosomes are small extracellular vesicles with diameters of 30-150 nm. In both physiological and pathological conditions, nearly all types of cells can release exosomes, which play important roles in cell communication and epigenetic regulation by transporting crucial protein and genetic materials such as miRNA, mRNA, and DNA. Consequently, exosome-based disease diagnosis and therapeutic methods have been intensively investigated. However, as in any natural science field, the in-depth investigation of exosomes relies heavily on technological advances. Historically, the two main technical hindrances that have restricted the basic and applied researches of exosomes include, first, how to simplify the extraction and improve the yield of exosomes and, second, how to effectively distinguish exosomes from other extracellular vesicles, especially functional microvesicles. Over the past few decades, although a standardized exosome isolation method has still not become available, a number of techniques have been established through exploration of the biochemical and physicochemical features of exosomes. In this work, by comprehensively analyzing the progresses in exosome separation strategies, we provide a panoramic view of current exosome isolation techniques, providing perspectives toward the development of novel approaches for high-efficient exosome isolation from various types of biological matrices. In addition, from the perspective of exosome-based diagnosis and therapeutics, we emphasize the issue of quantitative exosome and microvesicle separation.

Background: Natural nanostructure materials have been involved in antitumor drug delivery systems due to their biocompatibility, biodegradation, and bioactive properties. Methods: These materials have contributed to advanced drug delivery systems in the roles of both bioactive compounds and delivery nanocarriers. Fucoidan, a valuable ocean material used in drug delivery systems, has been exploited in research on cancer and a variety of other diseases. Results: Although the uniqueness, structure, properties, and health benefits of fucoidan have been mentioned in various prominent reviews, current developments and designs of fucoidan-based formulations still need to be assessed to further develop an effective anticancer therapy. In this review, current important formulations using fucoidan as a functional material and as an anticancer agent will be discussed. This article will also provide a brief principle of the methods that incorporate functional nanostructure materials in formulations exploiting fucoidan. Conclusion: Current research and future perspectives on the use of fucoidan in anticancer therapy will advance innovative and important products for clinical uses.

This study aims to develop mucoadhesive tablets containing solid lipid particles for controlled release pattern through buccal delivery. The buccal tablets containing drug-loaded solid lipid particles (SLPs) were fabricated using the ultrasonication method and lyophilisation with the incorporation of bioadhesive excipients. The role of stearic acid in the lipid phase and the effects of different surfactant contents were thoroughly evaluated. The stearic acid in formulations showed its impacts on particle formation and release characteristics. Although liquid surfactants could create SLPs of nano-size, the dissolution profile resulted in low drug release. The combination of a solid surfactant and a liquid surfactant resulted in better tablet formation and an improvement in the dissolution rate of prednisolone in both immediate release and sustained release. Furthermore, an adaptable pH surface, long mucoadhesion time, and satisfactory permeation resulted in suitable conditions for buccal tablet design without causing any irritations. The success of this work could contribute to a new strategy for improving the bioavailability of poorly water-soluble drugs by buccal delivery.

Although zein is a natural protein derived from corn, it has attracted much interest in pharmaceutical and biomedical sciences. Recent remarkable investigations on the use of zein in controlled drug delivery have contributed both important knowledge and potential applications of various products, particularly in the delivery of poorly water-soluble drugs. Zein has also been approved by the Food and Drug Administration for oral delivery. Substantial research has been performed to demonstrate the roles and promise of materials containing zein for pharmaceutical applications. Significant efforts have focused on the biodegradable and hydrophobic properties of zein and on technology using zein as a nanocarrier specifically for nanomedicine. However, important issues concerning the use of zein in technical advances and in the development of poorly water-soluble drugs must be addressed in order to use zein in translational research. This review aims to focus on the classification of potential approaches for using zein in the controlled release of poorly water-soluble drugs and to discuss recommended techniques for creating high-quality products from zein.

Despite their great potential, the nano-sized extracellular vesicles are yet to become effective delivery systems for poorly water-soluble drugs. Here, we present a novel platform of exosomes as a drug delivery system by engineering of a poorly water-soluble drug into a poloxamer-based molecular nanostructured dispersion composed of a hydrophilic and a hydrophobic moiety for an enhanced anticancer efficacy. For the first time, aspirin was loaded into exosomes as an anticancer agent via a one-step fabrication combining the nano-matrix formation of the nanostructured dispersion and exosomes loading. Our approach could transform crystalline aspirin to a nanoamorphous form in the nano-matrix structured exosomes, leading to increased drug encapsulation efficiency for exosomes, improved dissolution and strongly enhanced cytotoxicity of aspirin to cancer cells. Interestingly, cytotoxicity of aspirin to both breast and colorectal cancer cells could be strongly enhanced by the nanoamorphous aspirin-loaded exosomes, and this cytotoxic effect was more pronounced to parental cells of the exosomes, reminiscent of homing effect. Hence, this study has pioneered a novel nanoplatform of nanoamorphous exosomal delivery system to transform an anti-inflammatory drug into a potent anti-cancer agent.

The aim of this study was to investigate the impact of different chain length fatty acids on physicochemical properties and cancer targeting of fattigation-platform nanoparticles (NPs). Two different types of fatty acids (short chain, 2-hydroxybutyric acid, C4; long chain, oleic acid, C18:1) were successfully conjugated to human serum albumin (HSA) via simple 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) coupling reaction. These conjugates readily formed HSA-C4 and HSA-C18:1 NPs which showed good stability in serum and desirable biocompatibility with normal cell line (HEK293T). Doxorubicin hydrochloride (DOX) was efficiently loaded into NPs by incubation process via electrostatic interaction. The structure, morphology, and texture of DOX-loaded NPs were characterized by Transmission electron microscopy (TEM) equipped with Energy-dispersive X-ray spectroscopy (EDS). The initial burst release of DOX-loaded NPs was controlled by the presence and chain length of fatty acids. In vitro cytotoxicity studies with three cancer cell lines (A549, HT-29, and PANC-1) suggested that fattigation-platform NPs have distinctive cytotoxic effects compared to Doxil®. Confocal microscopy and flow cytometry exhibited that the cellular uptake of DOX-loaded NPs was varied by the different chain lengths of fatty acids. It was evident that the chain length of fatty acids in the fattigation-platform NPs could play a vital role in varying physicochemical properties and cancer cell targeting of NPs.

Two ATP-binding cassette transporters, ABCB1/MDR1 and ABCG2/BCRP, are considered the most critical determinants for chemoresistance in hepatocellular carcinoma. However, their roles in the chemoresistance in liver cancer stem cells remain elusive. Here we explored the role of inhibition of MDR1 or ABCG2 in sensitizing liver cancer stem cells to doxorubicin, the most frequently used chemotherapeutic agent in treating liver cancer. We show that the inhibition of MDR1 or ABCG2 in Huh7 and PLC/PRF/5 cells using either pharmacological inhibitors or RNAi resulted in the elevated level of intracellular concentration of doxorubicin and the accompanied increased apoptosis as determined by confocal microscopy, high-performance liquid chromatography, flow cytometry, and annexin V assay. Notably, the inhibition of MDR1 or ABCG2 led to the reversal of the chemoresistance, as evident from the enhanced death of the chemoresistant liver cancer stem cells in tumorsphere-forming assays. Thus, the elevation of effective intracellular concentration of doxorubicin via the inhibition of MDR1 or ABCG2 represents a promising future strategy that transforms doxorubicin from a traditional chemotherapy agent into a robust killer of liver cancer stem cells for patients undergoing transarterial chemoembolization.

Clays have been used in various health care products, including drug delivery systems. Advanced formulations have been investigated to take full advantage of clays or clay-based materials. The remarkable properties of clays, such as high adsorption, high surface area and high ion exchange capacities, provide an ideal system for the delivery of poorly water-soluble drugs. Currently, there is still limited information on the classification and discussion of clay-based formulations for poorly water-soluble drugs. This review aims to describe efficient delivery systems that use clay as the main excipient in formulations. More details regarding the strategies of using clays in formulations as well as fabrication methods will be discussed. Moreover, combinations with other excipients in hybrid formulations will also be mentioned and the efficacy of these systems will be evaluated. The recent studies on claybased formulations for poorly water-soluble drugs provide fundamental approaches and prospects to be applied in drug development.

The freeze-drying process has been particularly attractive for preparing tablets for controlled drug release. Although traditional methods, such as granulation or direct compression methods, have been used in various studies to produce tablets with controlled release, freeze-drying processes have been utilized in certain circumstances due to their distinct advantages. However, overall, further development of these strategies, which started with early studies on orally disintegrating tablets, is still necessary. In this review, the incorporation of different formulations into freeze-dried tablets will be discussed. Moreover, the use of excipients, freeze-drying conditions, formulation reconstitution and tablet structure for optimizing the performance of freeze-dried tablets will be reported, including strategies with nanoformulations and natural materials. Generally, this discussion with potential approaches will benefit further development of freeze-dried tablets containing drugs in the pharmaceutical industry.

BACKGROUND: The mucoadhesive polymers play an important role in targeted and controlled drug delivery. OBJECTIVES: This study aimed to investigate the drug release behaviour and interpret the role of mucoadhesive polymers involved in the coating layer of mucoadhesive tablets for the sustained release of a poorly water-soluble drug. METHODS: A solid dispersion of prednisolone and zein was used in the core tablets created with two mucoadhesive polymers, which included Carbopol 940 and hydroxypropyl methylcellulose K4M. In addition, the properties of a single-layer coating, created from the combination of zein and Kollicoat MAE 100P to delay release through the upper parts of the gastrointestinal tract, were investigated in the presence of the above mucoadhesive polymers; these properties included drug dissolution, mucoadhesion, surface morphology, swelling and erosion. RESULTS: The mucoadhesive polymer concentrations and types were integrated not only into the core tablets through a swelling/erosion mechanism but also into the surface polymer coatings for controlled drug release. HPMC was preferred in the formulations due to the ability to form pores on the surface coating, allowing water uptake so that the coating could control drug release for a later stage via a swelling/erosion mechanism. CONCLUSION: The proposed mechanism determined in this project could be beneficial in the selection of polymers for applications targeting the colon with coated mucoadhesive tablets. [Figure: see text]

Physicochemical characterization is a crucial step for the successful development of solid dispersions, including the determination of drug crystallinity and molecular interactions. Typically, the detection of molecular interactions will assist in the explanation of different drug performances (e.g., dissolution, solubility, stability) in solid dispersions. Various prominent reviews on solid dispersions have been reported recently. However, there is still no overview of recent techniques for evaluating the molecular interactions that occur within solid dispersions of poorly water-soluble drugs. In this review, we aim to overview common methods that have been used for solid dispersions to identify different bond formations and forces via the determination of interaction energy. In addition, a brief background on the important role of molecular interactions will also be described. The summary and discussion of methods used in the determination of molecular interactions will contribute to further developments in solid dispersions, especially for quick and potent drug delivery applications.

In recent decades, solid dispersions have been demonstrated as an effective approach for improving the bioavailability of poorly water-soluble drugs, as have solid dispersion techniques that include the application of nanotechnology. Many studies have reported on the ability to change drug crystallinity and molecular interactions to enhance the dissolution rate of solid dispersions using hydrophilic carriers. However, numerous studies have indicated that insoluble carriers are also promising excipients in solid dispersions. In this report, an overview of solid dispersion strategies involving insoluble carriers has been provided. In addition to the role of solubility and dissolution enhancement, the perspectives of the use of these polymers in controlled release solid dispersions have been classified and discussed. Moreover, the compatibility between methods and carriers and between drug and carrier is mentioned. In general, this report on solid dispersions using insoluble carriers could provide a specific approach and/or a selection of these polymers for further formulation development and clinical applications.

Background: Mucoadhesive polymers play a critical role in controlled-release tablets for buccal drug delivery. Objective: This research aimed to investigate the characterization and mechanisms of solid lipid particle-based tablets with different mucoadhesive polymers for buccal delivery. Methods: Prednisolone (PSL)-loaded solid lipid particles (SLPs) were conventionally prepared by ultrasonication. The freeze-drying method was used to convert the SLP suspension into a solid dosage form for buccal delivery by using mucoadhesive polymers. Results: All formulations showed over 80% drug release after 6 h, which followed immediate and sustained release patterns depending on the SLP type. However, the different polymers in the formulations resulted in different mucoadhesion times and drug release and drug permeability profiles. HPMC 4000 showed higher drug permeation (3327 μg vs. 2589 μg after 6 h) but a shorter mucoadhesion time than Carbopol (197 min vs. 361 min). In addition, surface morphology, swelling and erosion, particle size and zeta potential were also noted for the different mechanisms for buccal tablet design with different controlled release profiles. Conclusion: The results of this work indicate a good strategy for the selection of mucoadhesive polymers for SLP-based tablets in improving the bioavailability of poorly water-soluble drugs.

The objective of this study was to achieve an optimal formulation of hydrophilic-hydrophobic conjugates for nano-sized solid dispersions (SDs) with enhanced dissolution of multiple drugs in different gastrointestinal (GI) tract environments. A new conjugate powder with an optimized process was used to fabricate SDs that contained three poorly water-soluble drugs that were also poorly soluble in different dissolution media. The self-assembled nanoparticle formation, drug crystallinity and SD molecular interactions were investigated by measuring the particle size during dissolution testing and physicochemical property analysis (powder X-ray diffraction and Fourier transform infrared spectroscopy). Drug release studies indicated that SD containing conjugated powder significantly improved the dissolution rates of these poorly water-soluble drugs in the GI tract. In addition, particle size analysis showed nano-sized particles in the dissolution media in the early stage with a tendency to reduce smaller particles over time. Physicochemical characterizations demonstrated almost amorphous drug states and hydrogen bonding interactions between the drugs and conjugates in the SD. This study optimized a promising material for SD, and the material was shown to have a promising performance under various pH medium conditions with poorly water-soluble drugs.

Background: The aim of this study was to develop and compare polymeric micelles of fucoidan, a sulfated polysaccharide, and hydrophobic drugs such as paclitaxel and curcumin. Paclitaxel and curcumin are both known for their medicinal properties, including anticancer efficacy. However, their very low water solubility, absorption and rapid metabolism leads to reduced bioavailability. To redress these problems and enhance anti-cancer therapeutics using fucoidan, polymeric micelles were synthesized from conjugates of fucoidan and hydrophobic drugs. Methods: The chemical conjugation of fucoidan and hydrophobic drugs has been achieved by utilizing reactive functional groups on the molecules, such as carboxylic groups and hydroxyl groups. Results: The micelles revealed a homogeneous spherical morphology, size, negative surface charge. Fourier transform infrared spectroscopy was used to investigate the physicochemical properties of the polymeric micelles, which form a self-assembled polymeric micelle in aqueous medium. The results of the in vitro release of curcumin and fucoidan showed that their release rates were higher at a pH of 4.5 than at a pH of 7.4. In contrast, the paclitaxel conjugate had a similar release profile at pH of 4.5 and pH of 7.4. Conclusion: In the present work, we also found an effective drug delivery system that had the ability to release two types of anticancer drugs, fucoidan and hydrophobic drugs, in the tumour environment.

Background Ternary solid dispersions have been demonstrated to be an effective strategy in the improvement of drug absorption and bioavailability. Method The applications of the combination of hydrophilic polymers with the potential of hydrophobic polymer incorporation at moderate concentrations have been discussed in recent publications. Results In this paper, the general review of this specific type of solid dispersion will be provided with comprehensive understanding of polymer blends of either hydrophilic or hydrophobic polymers. A detailed description of miscible polymers has been developed in recent studies. In addition to dissolution rate improvement, the role of second polymers in crystal growth inhibition and in maintaining the amorphous state will be mentioned. Conclusion We also present a summary of characterization techniques commonly used to evaluate solid dispersion and polymer miscibility.

Albumin is the most abundant protein in blood, and is the most frequently identified protein in the protein corona of nanoparticles (NPs). Thus, albumin plays an important role in modulating NPs' physicochemical properties and bioavailability. In this study, the effect of bovine serum albumin (BSA) on gelatin-oleic nanoparticles' (GONs) physicochemical properties and cellular uptake were evaluated. Coumarin-6 was used as indicator to track the cellular uptake of GONs. The binding of BSA onto the GON surface increased the size, slightly reduced the negative net charge of the GON, and improved GON stability. The presence of BSA in cell culture media reduced the cellular uptake of BSA-uncoated GONs on human embryonic kidney cells 293 (HEK 293) and human adenocarcinoma alveolar basal epithelial cells (A549) in the media without FBS addition. Pre-coated BSA corona decreased cellular uptake of GONs in A549 cells in the media, with and without supplemented with 10% fetal bovine serum (FBS) but drastically increased cellular uptake on HEK 293 cells. BSA could be used to modulate protein corona as an endogenous ligand in NP design simply by mixing or incubating BSA with NPs before in vivo administration to inhibit or induce cellular uptake in specific cell types.

The aims of this work were to design pH-independent controlled release (CR) tablet containing nanonizing solid dispersion (SD) adsorbed on hydrophilic silica (Aeroperl® 300/30). Valsartan (VAL) was chosen to simultaneously modulate solubility and release rate due to its poor water solubility in low pH condition and short elimination half-life. Based on extensive equilibrium solubility and compatibility studies, poloxamer 407 was selected as a SD carrier. The melted mixtures of drug and poloxamer 407 were adsorbed onto hydrophilic fumed silica (Aeroperl® 300/30). Ternary SD system changed crystalline drug into an amorphous state and had intermolecular hydrogen bonding as confirmed by FT-IR with poloxamer 407. The dissolution rate of SD system was markedly enhanced as compared with pure VAL or commercial Diovan® tablet in simulated gastric fluid (pH 1.2). Interestingly, the particle size of SD system was gradually nanonized for 2 hr, ranging from 600 nm to 150 nm during dissolution process. The SD-loaded CR (SD-CR) tablets using hydroxypropylmethylcellulose (HPMC 4000) showed pH-independent zero-order release and good stability at accelerated conditions for six months. The SD-CR tablet showed minimized inter-subject variation of maximum plasma concentration as compared with commercial Diovan® tablets in healthy human volunteers.

BACKGROUND: The aim of this research was to engineer solid dispersion lipid particles (SD-SLs) in which a solid dispersion (SD) was encapsulated to form the core of solid lipid particles (SLs), thereby achieving an efficient enhancement in the dissolution of a poorly water-soluble drug. METHODS: Ultrasonication was introduced into the process to obtain micro/nanoscale SLs. The mechanism of dissolution enhancement was investigated by analysing the crystalline structure, molecular interactions, and particle size of the formulations. RESULTS: The drug release from the SD-SLs was significantly greater than that from the SD or SLs alone. This enhancement in drug release was dependent on the preparation method and the drug-to-polymer ratio of the SD. With an appropriate amount of polymer in the SD, the solidification method had the potential to alter the drug crystallinity to an amorphous state, resulting in particle uniformity and molecular interactions in the SD-SLs. CONCLUSIONS: The proposed system provides a new strategy for enhancing the dissolution rate of poorly water-soluble drugs and further improving their bioavailability.

Sprouted grains, which is a natural polysaccharide, is the subject of increasing scientific interest due to many benefits for human health. The aim of the present work was to develop sprouted rice (SR) as a safe and useful material for application in dissolution enhancement of anticancer poorly water-soluble drugs such as curcumin by solid dispersions (SDs). SDs were prepared with pure SR and modified sprouted rice (MSR) by the melting method. The dissolution rate, drug crystallinity changes, molecular interactions and wettability were characterized and compared between the formulations. The use of MSR could result in a promising system for improving the dissolution rate of poorly water-soluble drugs. MSR could induce a greater amorphous state and improved wettability of drugs for dissolution enhancement compared to SR. Although both SR and MSR showed hydrogen bonding interaction, insignificant differences between SR and MSR were observed. We found that the crystallinity, interactions and wettability of the drug were significantly affected and modulated by MSR.

Background Efficient colon-specific drug delivery has been demonstrated recently in the treatment of various diseases, including Crohn's disease, ulcerative colitis (inflammatory bowel disease), and colorectal cancer. Methods Of all strategies, the conjugation of a model drug to a carrier (with or without spacers) has been recognized as promising for targeting the colon. Results This is because the conjugation method releases large amounts of the drug while reducing the amount of the drug released in the stomach and small intestine. Conclusion This review focuses on the design of linkage conjugates that carry out specific delivery to the colon. The types of conjugation for application in colorectal cancer therapy will be discussed as well.

A major hurdle in cancer treatment is the precise targeting of drugs to the cancer site. As many cancer cells overexpress the transferrin receptor (TfR), the transferrin (Tf)-TfR interaction is widely exploited to target cancer cells. In this study, novel amphiphilic apo-Tf stearic acid (TfS) conjugates were prepared and characterized by Fourier transform infrared (FTIR) spectroscopy, matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry, and trinitrobenzenesulfonic acid (TNBS) assay. The prepared TfS conjugates were readily self-assembled in water to form nanoparticles (NPs), consisting of TfS as a core of NPs, whose sizes and zeta potentials were determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and a particle size analyzer. Hydrophilic water-soluble doxorubicin (DOX) was chosen as a model drug. DOX-loaded TfS NPs (NP+DOX), prepared by the adsorption of DOX on the NP surface via the incubation method, were analyzed for their cell targeting and killing efficiencies in TfR-overexpressing A549 and HCT116 cell lines by MTT assay, confocal microscopy, and fluorescence assisted cell sorting (flow cytometry). The data showed that NP+DOX exhibited improved cancer cell targeting and killing properties compared to that reported for free DOX. Further, the cytotoxic efficiency of NP+DOX was comparable to that of PEGylated liposomal product, Doxil®, while its cellular uptake was higher than that of Doxil®. Thus, this novel receptor-based TfS NP drug delivery system has great potential to target TfR-overexpressing cancer cells without off-target effects.

Poorly water-soluble drugs, which commonly face the issue of poor absorption and low bioavailability, have been under ongoing research of many formulation scientists for the past few decades. Solid dispersion is one of the most effective strategies in concerns for improving bioavailability of poorly water-soluble drugs. Either application of solid dispersions in dissolution enhancement of poorly water-soluble drugs or the use of swellable polymers in controlled drug release has been reported in pharmaceutical designs widely. However, a review of strategies of using swellable polymers in solid dispersion to take a full advantage of these polymers as a current perspective in facilitating drug bioavailability enhancement is still missing. In this review, we aim to provide a summary of techniques used to formulate a swellable polymer in solid dispersion especially a description of a suitable fabrication method in design of a controlled release solid dispersion.

Gene therapy has a strong potential in neuroscience by suppressing or replacing abnormalities in genetic materials. The employment of nano-gene carrier for neurological disorders is comparatively young and restricted since the aim to effectively deliver therapeutic agents into the central nervous system (CNS) commonly has confronted difficulties of several natural occurring barriers in the body and unfavorable characteristics of pharmaceutical agents. Two major anatomical and biochemical barriers are blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB), which significantly prevent permeation of most drugs and genes to brain parenchyma. In this concern, nanotechnology emerges as an innovative method for transporting therapeutics to the CNS. Diverse nano-systems have been closely investigated, some of which have demonstrated initial success for in vivo studies. The perspectives of nanotechnology for gene therapy would be a promising field to be further explored in the near future.

Sonication-assisted nanoprecipitation provides an effective tool for nanomedicine engineering in therapeutic improvement. In the scope of this review, original works in interdisciplinary areas of using sonication with precipitation method for nanoparticulate drug delivery systems and its applications in management of different diseases are discussed. The use of sonication-assisted nanoprecipitation has been proved to improve drug bioavailability, which attracts tremendous interests as an effective strategy for drug delivery. However, many challenges still remain. To overcome these barriers, different approaches such as precipitation method, rational design, optimization and modification have been investigated. Accordingly, current knowledge of sonication-assisted nanoprecipitation proposes a broad perspective and optimization for the applications of nanotechnology in drug delivery.

In this study, the population pharmacokinetic (PK) analysis of rebamipide (Reba) in healthy male Korean subjects was analyzed using the nonlinear mixed effects modeling method. The possible effects of physiological covariates and the multidrug resistance (MDR1) gene 3435C>T polymorphism on PK parameters were also investigated. Data were collected from a bioequivalence study, in which 26 subjects who participated in the study were administered a single oral dose of 100 mg Reba; only data from the reference formulation were used. Reba showed a relatively large inter-individual variability (from 2.6- to 3.3-fold) in the PK parameters with double peaks or the concentration plateau after the peak concentration in its serum concentration–time profiles. The population PKs of Reba was best described by a one-compartment model with three fraction absorption processes followed a single Weibull-type function and two first-order kinetics, and lag times. The study suggests that the efflux transporter MDR1 3435C>T allele affects the substantial inter-individual variability in the absorption of Reba according to genetic polymorphism. A significant difference was found in the absorption rate ka 1 among the MDR1 3435C>T genotype groups (P T and body mass index as covariates for ka 1 exerted a more significant effect (P

Microemulsion has the potentials to enhance dissolution as well as facilitate absorption and permeation of poorly water-soluble drugs through biological membranes. However, its application to govern a controlled release buccal delivery for local treatment has not been discovered. The aim of this study is to develop microemulsion-based mucoadhesive wafers for buccal delivery based on an incorporation of the microemulsion with mucoadhesive agents and mannitol. Ratio of oil to surfactant to water in the microemulsion significantly impacted quality of the wafers. Furthermore, the combination of carbopol and mannitol played a key role in forming the desired buccal wafers. The addition of an extra 50% of water to the formulation was suitable for wafer formation by freeze-drying, which affected the appearance and distribution of carbopol in the wafers. The amount of carbopol was critical for the enhancement of mucoadhesive properties and the sustained drug release patterns. Release study presented a significant improvement of the drug release profile following sustained release for 6 h. Ex vivo mucoadhesive studies provided decisive evidence to the increased retention time of wafers along with the increased carbopol content. The success of this study indicates an encouraging strategy to formulate a controlled drug delivery system by incorporating microemulsions into mucoadhesive wafers.

The study aims to design and evaluate the ability of zein in solid dispersion (SD) system to enhance drug dissolution rate for a further application of colonic delivery of poorly water-soluble drug. The SD samples were prepared by solvent method and the investigation of drug release was performed at pH 7.4. The wettability, molecular interactions and drug’s crystal behaviours of SDs were studied by contact angle measurement, Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (PXRD), respectively. Zein-based SDs showed its potential in enhancing the rate of drug release. The PXRD results pointed out a rearrangement of drug’s crystalline structure in some SD samples through the appearance of new peaks on PXRD diffractogram, while a formation of a hydrogen bond between prednisolone (PRL) and zein was also confirmed by FTIR spectra. It was evident that a strong relationship between the amount of zein and the dissolution rate of PRL in SD system attributed to zein hydrophobicity, recrystallization and molecular interaction which were factors inducing the enhanced drug release rate. In conclusion, zein is a potential carrier for controlled release SD systems, especially further application for poorly water-soluble drugs in colonic delivery like PRL due to the resistance of zein at low pH environment.

An accurate, precise, selective, and sensitive liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of imperatorin (IMP) and its metabolite, xanthotoxol (XAN), in rat plasma and urine samples. The analytes, along with psoralen as an internal standard, were determined by multiple reaction monitoring (MRM) operated in the positive electrospray ionization (ESI) mode. Chromatographic separation was performed on an Acquity UPLC BEH C18 column (50mm×2.1mm, 1.7μm) with a mobile phase consisting of 0.1% formic acid solution and 0.1% formic acid in methanol at a flow rate of 0.3mL/min. The run time was 6min per sample and the injection volume was 5μL. The method had a lower limit of quantification (LLOQ) of 0.25ng/mL for IMP in plasma and urine, and 1ng/mL for XAN in urine. The linear calibration curves were fitted over the range of 0.25-1000ng/mL for IMP in plasma, 0.25-1000ng/mL for IMP in urine, and 1-1000ng/mL for XAN in urine, with correlation coefficients greater than 0.995. The inter- and intra-day accuracies (relative error, RE%) were between -8.5% and 3.5%, and the precisions (relative standard deviation, RSD%) were less than 10.0% for all quality control samples (QCs). The analytes were extracted from rat plasma and urine samples using a liquid-liquid extraction method with the extraction recovery in the range of 60.3-79.1%. A good stability of the analytes was observed in all the analysis procedures. The method was successfully validated and applied to determine the pharmacokinetics of IMP in rat plasma and, for the first time, the metabolite kinetics of IMP to XAN in rat urine after IMP administration.

Although synthetic materials have been used in film coating processes for drug delivery for many years, substantial studies on natural materials have also been conducted because of their biodegradable and unique properties. Methods: Because of the ability to form and modify films for controlled oral drug delivery, increasing attention has been shown to these materials in the design of film coating systems in recent research. Results: This review aims to provide an overview of natural materials focusing on film coating for oral delivery, specifically in terms of their classification and their combinations in film coating formulations for adjusting the desired properties for controlled drug delivery. Conclusion: Discussing natural materials and their potential applications in film coating would benefit the optimization of processes and strategies for future utilization.

Targeted exosomal delivery systems for precision nanomedicine attract wide interest across areas of molecular cell biology, pharmaceutical sciences, and nanoengineering. Exosomes are naturally derived 50-150 nm nanovesicles that play important roles in cell-to-cell and/or cell-to-tissue communications and cross-species communication. Exosomes are also a promising class of novel drug delivery vehicles owing to their ability to shield their payload from chemical and enzymatic degradations as well as to evade recognition by and subsequent removal by the immune system. Combined with a new class of affinity ligands known as aptamers or chemical antibodies, molecularly targeted exosomes are poised to become the next generation of smartly engineered nanovesicles for precision medicine. Here, recent advances in targeted exosomal delivery systems engineered by aptamer for future strategies to promote human health using this class of human-derived nanovesicles are summarized.

Background:: An increase in poorly water-soluble drugs makes the design of drug delivery systems challenging. Methods:: Currently, a number of prospective solid dispersions have been investigated with potential applications for delivering a variety of poorly water-soluble drugs. A number of traditional solid dispersions and modifiedsolid dispersions offer attractive advantages in the fabrication, design and development of those drugs for effective therapeutics. Results:: Although traditional solid dispersions can produce a higher release rate, resulting in higher bioavailability compared to conventional dosage forms, this method is not always a promising approach. Modified-solid dispersion has demonstrated both the ability of its polymers to transform drug crystals into amorphous forms and molecular interactivity, thereby improving drug dissolution rate and bioavailability, especially with tough drugs. However, the classification of modified-solid dispersion, which guides the selection of the right strategy in solid dispersion preparation, remains ill-defined. Conclusions:: This review focused on effective strategies in using additives in solid dispersion for improving drug bioavailability.