Development and Characterization of Chitosan Microparticles-in-Films for Buccal Delivery of Bioactive Peptides

Whey Protein Isolate as a Substrate to Design Calendula officinalis Flower Extract Controlled-Release Materials

The use of natural active substances and the development of new formulations are promising directions in the cosmetic and pharmacy industries. The primary purpose of this research was the production of microparticles based on whey protein isolate (WPI) and calcium alginate (ALG) containing Calendula officinalis flower extract and their incorporation into films composed of gelatin, WPI, and glycerol. Both swollen and dry microparticles were studied by optical microscopy and their sizes were measured. Water absorption by the microparticles, their loading capacity, and the release profile of flower extract were also characterized. The films were analyzed by mechanical tests (Young's modulus, tensile strength, elongation at break), swelling capacity, contact angle, and moisture content measurements. The presented data showed that the active ingredient was successfully enclosed in spherical microparticles and completely released after 75 min of incubation at 37 °C. The incorporation of the microparticles into polymer films caused a decrease in stiffness and tensile strength, simultaneously increasing the ductility of the samples. Moreover, the films containing microparticles displayed higher swelling ability and moisture content compared to those without them. Hence, the materials prepared in this study with Calendula officinalis flower extract encapsulated into polymeric microspheres can be a starting point for the development of new products intended for skin application; advantages include protection of the extract against external factors and a controlled release profile.

Tamarind seed polysaccharide-guar gum buccal films loaded with resveratrol-bovine serum albumin nanoparticles: Preparation, characterization, and mucoadhesiveness assessment

Mucoadhesive films based on tamarind seed polysaccharide and guar gum (TSP-GG) were formulated for buccal delivery of resveratrol. Resveratrol-bovine serum albumin nanoparticles (Res-BSA) were prepared and dispersed in TSP-GG to improve its buccal mucoadhesiveness. The impregnation of Res-BSA induced the dense internal structures of TSP-GG and improved its strength and rigidity. Structural characterization showed that resveratrol existed in an amorphous state in the films containing Res-BSA, and hydrogen bonding was formed between Res-BSA and the film matrices. The films containing Res-BSA exhibited good uniformity in thickness, weight, and resveratrol content, and their surface pH was near neutral, ranging between 6.78 and 7.09. Increasing Res-BSA content reduced the water contact angle of TSP-GG (from 75.9° to 59.6°). The swelling and erosion studies indicated the favorable hydration capacity and erosion resistance of the films containing Res-BSA. Additionally, the addition of Res-BSA imparted enhanced ex vivo mucoadhesive force, in the range of 1.53 N to 1.98 N, and extended ex vivo residence time, between 17.9 h and 18.9 h, to TSP-GG. The current study implied that the composite systems of TSP-GG and Res-BSA may be a novel platform for buccal mucosal delivery of resveratrol.

The Potential of Films as Transmucosal Drug Delivery Systems

Pharmaceutical films are polymeric formulations used as a delivery platform for administration of small and macromolecular drugs for local or systemic action. They can be produced by using synthetic, semi-synthetic, or natural polymers through solvent casting, electrospinning, hot-melt extrusion, and 3D printing methods, and depending on the components and the manufacturing methods used, the films allow the modulation of drug release. Moreover, they have advantages that have drawn interest in the development and evaluation of film application on the buccal, nasal, vaginal, and ocular mucosa. This review aims to provide an overview of and critically discuss the use of films as transmucosal drug delivery systems. For this, aspects such as the composition of these formulations, the theories of mucoadhesion, and the methods of production were deeply considered, and an analysis of the main transmucosal pathways for which there are examples of developed films was conducted. All of this allowed us to point out the most relevant characteristics and opportunities that deserve to be taken into account in the use of films as transmucosal drug delivery systems.

Quality by Design-Guided Systematic Development and Optimization of Mucoadhesive Buccal Films

Mucoadhesive buccal films have found increased popularity in pharmaceutical drug delivery due to the several advantages that they possess. The present study strives to develop and optimize chitosan-based mucoadhesive buccal films by relying on quality-by-design (QbD) principles. Previous knowledge and experience were employed to firstly identify the critical quality attributes (CQAs), followed by a thorough risk assessment, which led to the selection of seven critical material attributes and process parameters, namely, the polymer grade and concentration, the plasticizer type and concentration, the citric acid (CA) concentration, the amount of the casted solution, and the drying condition. Their effects on the breaking hardness and mucoadhesivity, selected as CQAs, were investigated in three steps by three designs of the experiment (DoE). The medium molecular weight of chitosan (CH) was the preferred choice in the optimized formulation, and its concentration was the most important factor affecting the CQAs, thickness, and moisture content of the films. It was found that 0.364 g/cm2 was the suitable amount of the casting solution, and its optimum drying conditions were presented in the form of a design space. Glycerol (Gly) was the best choice as a plasticizer, and a design space representing several combinations of CH and CA concentrations that produce films with the required quality was constructed at a fixed concentration of 35% Gly. A formula from this design space was selected and employed to load with two model drugs to test its drug-carrying properties for drugs with different physicochemical characteristics. Uniform drug distribution with an immediate release profile was achieved in both drugs, although one of the CQAs was outside of the specifications in the case of lidocaine-containing film. To summarize, the obtention of the optimum mucoadhesive buccal film based on CH was efficiently facilitated by the rational application of QbD principles and the DoE approach.

Eco-friendly synthesis of chitosan and its medical application: from chitin extraction to nanoparticle preparation

Background and Purpose

Chitosan, a chitin deacetylation product, has been applied in nanoparticle or nano-chitosan for medical applications. However, the chitin extraction from crustacean shells and other natural resources, chitin deacetylation, and crosslinking of the chitosan forming the nano-chitosan mostly involve hazardous chemical and physical processes. The risks of these processes to human health and the environment attract the attention of scientists to develop safer and greener techniques. This review aims to describe the progress of harmless chitosan synthesis.

Experimental Approach

All strongly related publications to each section, which were found on scientific search engines (Google Scholar, Scopus, and Pubmed), were studied, selected, and then used as references in writing this review. No limitation for the publication year was applied. The publications were searched from April 2022 - June 2023.

Key Results

Nano-chitosan could be synthesized in harmless techniques, including the preparation of the chitosan raw materials and crosslinking the chitosan polymer. Enzymatic processes in shell deproteination in the chitin extraction and deacetylation are preferable to reduce the negative effects of conventional chemical-physical processes. Mild alkalines and deep eutectic solvents also provide similar benefits. In the nano-chitosan synthesis, naturally derived compounds (carrageenan, genipin, and valinin) show potency as safer crosslinkers, besides tripolyphosphate, the most common safe crosslinker.

Conclusion

A list of eco-friendly and safer processes in the synthesis of nano-chitosan has been reported in recent years. These findings are suggested for the nano-chitosan synthesis on an industrial scale in the near future.

Contemporary Aspects of Designing Marine Polysaccharide Microparticles as Drug Carriers for Biomedical Application

The main goal of modern pharmaceutical technology is to create new drug formulations that are safer and more effective. These formulations should allow targeted drug delivery, improved drug stability and bioavailability, fewer side effects, and reduced drug toxicity. One successful approach for achieving these objectives is using polymer microcarriers for drug delivery. They are effective for treating various diseases through different administration routes. When creating pharmaceutical systems, choosing the right drug carrier is crucial. Biomaterials have become increasingly popular over the past few decades due to their lack of toxicity, renewable sources, and affordability. Marine polysaccharides, in particular, have been widely used as substitutes for synthetic polymers in drug carrier applications. Their inherent properties, such as biodegradability and biocompatibility, make marine polysaccharide-based microcarriers a prospective platform for developing drug delivery systems. This review paper explores the principles of microparticle design using marine polysaccharides as drug carriers. By reviewing the current literature, the paper highlights the challenges of formulating polymer microparticles, and proposes various technological solutions. It also outlines future perspectives for developing marine polysaccharides as drug microcarriers.

Development and Characterization of Microparticles with Actinidia arguta Leaves Extract by Spray-Drying: A New Mind-Set Regarding Healthy Compounds for Oral Mucositis

Actinidia arguta leaves have gained notoriety over the past years due to their rich bioactive composition with human pro-healthy effects, particularly in relation to antioxidants. Nevertheless, antioxidants are well known for their chemical instability, making it necessary to develop suitable delivery systems, such as microparticles, to provide protection and ensure a controlled release. The aim of this work was to produce polymeric particles of A. arguta leaves extract by spray-drying that may improve the oral mucositis condition. Microparticles were characterized by size, shape, antioxidant/antiradical activities, swelling capacity, moisture content, and effect on oral cells (TR146 and HSC-3) viability, with the aim to assess their potential application in this oral condition. The results attested the microparticles' spherical morphology and production yields of 41.43% and 36.40%, respectively, for empty and A. arguta leaves extract microparticles. The A. arguta leaves extract microparticles obtained the highest phenolic content (19.29 mg GAE/g) and antioxidant/antiradical activities (FRAP = 81.72 µmol FSE/g; DPPH = 4.90 mg TE/g), being perceived as an increase in moisture content and swelling capacity. No differences were observed between empty and loaded microparticles through FTIR analysis. Furthermore, the exposure to HSC-3 and TR146 did not lead to a viability decrease, attesting their safety for oral administration. Overall, these results highlight the significant potential of A. arguta leaves extract microparticles for applications in the pharmaceutical and nutraceutical industries.

Polymeric Biomaterials for Topical Drug Delivery in the Oral Cavity: Advances on Devices and Manufacturing Technologies

There are several routes of drug administration, and each one has advantages and limitations. In the case of the topical application in the oral cavity, comprising the buccal, sublingual, palatal, and gingival regions, the advantage is that it is painless, non-invasive, allows easy application of the formulation, and it is capable of avoiding the need of drug swallowing by the patient, a matter of relevance for children and the elderly. Another advantage is the high permeability of the oral mucosa, which may deliver very high amounts of medication rapidly to the bloodstream without significant damage to the stomach. This route also allows the local treatment of lesions that affect the oral cavity, as an alternative to systemic approaches involving injection-based methods and oral medications that require drug swallowing. Thus, this drug delivery route has been arousing great interest in the pharmaceutical industry. This review aims to condense information on the types of biomaterials and polymers used for this functionality, as well as on production methods and market perspectives of this topical drug delivery route.

Oromucosal delivery of macromolecules: Challenges and recent developments to improve bioavailability

Owing to their biological diversity, high potency, good tolerability, low immunogenicity, site-specific activity, and great efficacy, macromolecular drugs (i.e., proteins and peptides, antibodies, hormones, nucleic acids, vaccines, etc.) are extensively used as diagnostics, prophylactics, and therapeutics in various diseases. To overcome drawbacks associated with parenteral (invasive) delivery of macromolecules as well as to preserve their therapeutic integrity, oromucosal route (sublingual and buccal) has been proven efficient alternate port of delivery. This review aims to summarize challenges associated with oromucosal route and overtime developments in conventional delivery systems with special emphasis on most recent delivery strategies. Over the past few decades, significant efforts have been made for improving the oromucosal absorption of macromolecules by employing chemical penetration enhancers (CPE), enzyme inhibitors, chemical modification of drug structure (i.e., lipidation, PEGylation, etc.), and mucoadhesive materials in the form of buccal tablets, films (or patches), sprays, fast disintegrating tablets, and microneedles. Adaptation of adjunct strategies (e.g., iontophoresis in conjunction with CPE) has shown significant improvement in oromucosal absorption of macromolecules; however, these approaches were also associated with many drawbacks. To overcome these shortcomings and to further improve therapeutic outcomes, specialized delivery devices called "hybrid nanosystems" have been designed in recent times. This newer intervention showed promising potential for promoting oromucosal absorption and absolute bioavailability of macromolecules along with improved thermostability (cold chain free storage), enabling self-administration, site-specific activity, improving therapeutic efficacy and patient compliance. We anticipate that tailoring of hybrid nanosystems to clinical trials as well as establishing their short- and long-term safety profile would substantiate their therapeutic value as pharmaceutical devices for oromucosal delivery of macromolecules.

Patches as Polymeric Systems for Improved Delivery of Topical Corticosteroids: Advances and Future Perspectives

Mucoadhesive polymer patches are a promising alternative for prolonged and controlled delivery of topical corticosteroids (CS) to improve their biopharmaceutical properties (mainly increasing local bioavailability and reducing systemic toxicity). The main biopharmaceutical advantages of patches compared to traditional oral dosage forms are their excellent bioadhesive properties and their increased drug residence time, modified and unidirectional drug release, improved local bioavailability and safety profile, additional pain receptor protection, and patient friendliness. This review describes the main approaches that can be used for the pharmaceutical R&D of oromucosal patches with improved physicochemical, mechanical, and pharmacological properties. The review mainly focuses on ways to increase the bioadhesion of oromucosal patches and to modify drug release, as well as ways to improve local bioavailability and safety by developing unidirectional -release poly-layer patches. Various techniques for obtaining patches and their influence on the structure and properties of the resulting dosage forms are also presented.

Synthesis, characterization, and biological activities of new conjugates of Guanosine grafted on polyvinyl alcohol, carbohydrate chitosan, and cellulose

Guanosine (GU) is a purine nucleoside that has different biological applications. This study aimed to synthesize, characterize, and enhance the biological activities of GU through its covalently grafting on polyvinyl alcohol (PVA), chitosan (CS), and cellulose (CL). In this regard, the conjugation was constructed by different linkers such as chloroacetyl chloride, 2-bromopropionyl bromide, and epichlorohydrin (EPCH). The resulted novel conjugates were characterized by FT-IR, 1H-NMR, GPC, and TGA techniques. FT-IR spectra revealed the main characteristic groups, O–H, N–H, C=O and C=N of GU moieties. Furthermore, 1H-NMR spectra showed the aromatic C–H, O–H, and N–H protons of the grafted GU moieties. Two decomposition stages of grated polymers with high thermal stability are illustrated by TGA. GU showed no antifungal activity against Aspergillus fumigatus and Candida albicans. However, its conjugates: P-1A, P-1B, P-2A, P-2B, P-3A, and P-3B displayed significant antifungal effect with inhibitory zones in the range 8–11 mm. As compared to GU group, most of GU-polymer conjugates showed significant in vivo antitumor activity against EAC-bearing mice via the reduction in total tumor volume. In summary, these conjugates are biologically active macromolecules and may act as candidate carrier systems for other applications such as drug delivery.

Multiple Roles of Chitosan in Mucosal Drug Delivery: An Updated Review

Chitosan (CS) is a linear polysaccharide obtained by the deacetylation of chitin, which, after cellulose, is the second biopolymer most abundant in nature, being the primary component of the exoskeleton of crustaceans and insects. Since joining the pharmaceutical field, in the early 1990s, CS attracted great interest, which has constantly increased over the years, due to its several beneficial and favorable features, including large availability, biocompatibility, biodegradability, non-toxicity, simplicity of chemical modifications, mucoadhesion and permeation enhancer power, joined to its capability of forming films, hydrogels and micro- and nanoparticles. Moreover, its cationic character, which renders it unique among biodegradable polymers, is responsible for the ability of CS to strongly interact with different types of molecules and for its intrinsic antimicrobial, anti-inflammatory and hemostatic activities. However, its pH-dependent solubility and susceptibility to ions presence may represent serious drawbacks and require suitable strategies to be overcome. Presently, CS and its derivatives are widely investigated for a great variety of pharmaceutical applications, particularly in drug delivery. Among the alternative routes to overcome the problems related to the classic oral drug administration, the mucosal route is becoming the favorite non-invasive delivery pathway. This review aims to provide an updated overview of the applications of CS and its derivatives in novel formulations intended for different methods of mucosal drug delivery.

Recent Fabrication Methods to Produce Polymer-Based Drug Delivery Matrices (Experimental and In Silico Approaches)

The study of novel drug delivery systems represents one of the frontiers of the biomedical research area. Multi-disciplinary scientific approaches combining traditional or engineered technologies are used to provide major advances in improving drug bioavailability, rate of release, cell/tissue specificity and therapeutic index. Biodegradable and bio-absorbable polymers are usually the building blocks of these systems, and their copolymers are employed to create delivery components. For example, poly (lactic acid) or poly (glycolic acid) are often used as bricks for the production drug-based delivery systems as polymeric microparticles (MPs) or micron-scale needles. To avoid time-consuming empirical approaches for the optimization of these formulations, in silico-supported models have been developed. These methods can predict and tune the release of different drugs starting from designed combinations. Starting from these considerations, this review has the aim of investigating recent approaches to the production of polymeric carriers and the combination of in silico and experimental methods as promising platforms in the biomedical field.

Untangling Mucosal Drug Delivery: Engineering, Designing, and Testing Nanoparticles to Overcome the Mucus Barrier

Mucus is a complex viscoelastic gel and acts as a barrier covering much of the soft tissue in the human body. High vascularization and accessibility have motivated drug delivery to various mucosal surfaces; however, these benefits are hindered by the mucus layer. To overcome the mucus barrier, many nanomedicines have been developed, with the goal of improving the efficacy and bioavailability of drug payloads. Two major nanoparticle-based strategies have emerged to facilitate mucosal drug delivery, namely, mucoadhesion and mucopenetration. Generally, mucoadhesive nanoparticles promote interactions with mucus for immobilization and sustained drug release, whereas mucopenetrating nanoparticles diffuse through the mucus and enhance drug uptake. The choice of strategy depends on many factors pertaining to the structural and compositional characteristics of the target mucus and mucosa. While there have been promising results in preclinical studies, mucus-nanoparticle interactions remain poorly understood, thus limiting effective clinical translation. This article reviews nanomedicines designed with mucoadhesive or mucopenetrating properties for mucosal delivery, explores the influence of site-dependent physiological variation among mucosal surfaces on efficacy, transport, and bioavailability, and discusses the techniques and models used to investigate mucus-nanoparticle interactions. The effects of non-homeostatic perturbations on protein corona formation, mucus composition, and nanoparticle performance are discussed in the context of mucosal delivery. The complexity of the mucosal barrier necessitates consideration of the interplay between nanoparticle design, tissue-specific differences in mucus structure and composition, and homeostatic or disease-related changes to the mucus barrier to develop effective nanomedicines for mucosal delivery.

Validation of Psychophysiological Measures for Caffeine Oral Films Characterization by Machine Learning Approaches

(1) Background: The oral films are a new delivery system that can carry several molecules, such as neuromodulator molecules, including caffeine. These delivery systems have been developed and characterized by pharmacokinetics assays. However, new methodologies, such as psychophysiological measures, can complement their characterization. This study presents a new protocol with psychophysiological parameters to characterize the oral film delivery systems based on a caffeine model. (2) Methods: Thirteen volunteers (61.5% females and 38.5% males) consumed caffeine oral films and placebo oral films (in different moments and without knowing the product). Electrocardiogram (ECG), electrodermal (EDA), and respiratory frequency (RF) data were monitored for 45 min. For the data analysis, the MATLAB environment was used to develop the analysis program. The ECG, EDA, and RF signals were digitally filtered and processed, using a windowing process, for feature extraction and an energy mean value for 5 min segments. Then, the data were computed and presented to the entries of a set of Machine Learning algorithms. Finally, a data statistical analysis was carried out using SPSS. (3) Results: Compared with placebo, caffeine oral films led to a significant increase in power energy in the signal spectrum of heart rate, skin conductance, and respiratory activity. In addition, the ECG time-series power energy activity revealed a better capacity to detect caffeine activity over time than the other physiological modalities. There was no significant change for the female or male gender. (4) Conclusions: The protocol developed, and the psychophysiological methodology used to characterize the delivery system profile were efficient to characterize the drug delivery profile of the caffeine. This is a non-invasive, cheap, and easy method to apply, can be used to determine the neuromodulator drugs delivery profile, and can be implemented in the future.

Investigation of Surface Properties and Free Volumes of Chitosan-Based Buccal Mucoadhesive Drug Delivery Films Containing Ascorbic Acid

Nowadays, the buccal administration of mucoadhesive films is very promising. Our aim was to prepare ascorbic acid-containing chitosan films to study the properties and structures important for applicability and optimize the composition. During the formulation of mucoadhesive films, chitosan as the polymer basis of the film was used. Ascorbic acid, which provided the acidic pH, was used in different concentrations (2–5%). The films were formulated by the solvent casting method. The properties of films important for applicability were investigated, such as physical parameters, mucoadhesive force, surface free energy, and breaking strength. The fine structure of the films was analyzed by atomic force microscopy, and the free volume was analyzed by PALS, which can be important for drug release kinetics and the location of the drug in the film. The applicability of the optimized composition was also tested with two different types of active ingredients. The structure of the films was also analyzed by XRPD and FTIR. Ascorbic acid can be used well in chitosan films, where it can function as a permeation enhancer when reacting to chitosan, it is biodegradable, and can be applied in 2% of our studies.

Formulation and Evaluation of Topical Biodegradable Films Loaded with Levofloxacin Lipid Nanocarriers

Skin ulcers have increased sharply due to rise in the incidence of obesity and diabetes. This study investigated lipid nanocarriers as a strategy to improve the efficacy of levofloxacin (LV) in penetrating skin. Two surfactant types and different lipid mixtures were used in preparation of lipid nanocarriers. Mean particle size, percentage entrapment efficiency (%EE), in vitro release, and antimicrobial activity were examined. The selected formula was incorporated into a chitosan (CS) film that was subjected to physic-chemical characterization and ex vivo permeation study. The selected formula showed particle size, PDI, and ZP: 80.3 nm, -0.21, and -26 mV, respectively, synchronized with 82.12 %EE. In vitro release study showed slow biphasic release of LV from lipid nanocarriers. The antimicrobial effect illustrated statistically significant effect of lipid nanocarriers on decreasing the minimum effective concentration (MIC) of LV, particularly against E. coli. The optimized nanocarriers' formula loaded into CS film was clear, colorless, translucent, and smooth in texture. Based on the release profiles, it could be speculated that the CS film loaded with LV nanocarriers can maintain the antibacterial activity for 4 consecutive days. Thus, the local delivery of the drug in a sustained release manner could be predicted to enhance the therapeutic effect. Further clinical studies are strongly recommended. Graphical Abstract.

In Silico Factorial Screening and Optimization of Chitosan Based Gel for Urapidil Loaded Microparticle using Reduced Factorial Design

OBJECTIVE

Literature study revealed the poor mechanical strength of chitosan-based microparticles. Our research aimed at developing sufficient strength of microparticle with a suitable concentration of chitosan and non-ionic surfactants such as poloxamer-188 (pluronic). It also aimed to develop and study the effect of variables for prepared microparticles utilizing insilico screening methodology, such as reduced factorial design, followed by optimization.

METHODS

Preliminary trial batches were prepared with variable concentration of chitosan and poloxamer-188 utilizing cross-linked ion-gelation technique. A 20% w/v sodium citrate solution was used as a cross-linking solution. The resolution-IV of 24-1 reduced factorial design was selected to screen the possible and significant independent variables or factors in the dosage form design. A total number of eight runs were suggested by statistical software and responses were recorded. The responses such as spreadability, pH, viscosity and percentage of drug released at 12 h were considered in the screening study. Based on the result, selected factors were included in the optimization technique, including graphical and numerical methods.

RESULTS

The signified factors based on reduced two-level factorial screening design with randomized subtype, were identified by Half-normal and Pareto chart. Mathematical fitting and analysis were performed by the factorial equation during the optimization process. The validation and fitting of models were suggested and evaluated by p-value, adjusted R2, and predicted R2 values. The significant and non-significant terms were evaluated, followed by finding the optimal concentration and region with yellow color highlighted in an overlay plot. Based on the data obtained by the overlay study, the final formulation batch was prepared and the observed value was found to be pretty much nearer as compared to predicted values. Drug-polymer interaction study included attenuated total reflectance, differential scanning calorimetry, and X-Ray diffraction study.

CONCLUSION

The principal of the study design was based on finding the prefixed set parameter values utilizing the concept of in-silico screening technique and optimization with a minimal number of trials and study expenses. It concluded that Poloxamer-188 (0.94%), chitosan (2.38%), swelling time (1.81 h), and parts of chitosan (78.51%) in a formulation batch would fulfill the predetermined parameter with specific values.

Freeze-Dried Matrices Composed of Degradable Polymers with Surfactant-Loaded Microparticles Based on Pectin and Sodium Alginate

Gelatin/polyvinylpyrrolidone/hydroxyethyl cellulose/glycerol porous matrices with microspheres made of sodium alginate or pectin and sodium alginate were produced. A surfactant was loaded into these microparticles. The microspheres were characterized using optical microscopy, scanning electron microscopy SEM, and laser diffraction particle size analyzer. For the matrices, the density, porosity, swelling capacity, dissolution in phosphate saline buffer were determined and SEM, mechanical, and thermogravimetric studies were applied. The results showed that the size of the two-component microspheres was slightly larger than that of single-ingredient microparticles. The images confirmed the spherical shape of the microparticles. The prepared matrices had high water uptake ability and porosity due to the presence of hydrophilic polymers. The presence of microparticles in the matrices caused a decrease in these parameters. Degradation of the composites with the microspheres was significantly faster than the matrix without them. The addition of microparticles increased the stiffness and toughness of the prepared materials. The efficiency of the thermal decomposition main stage was reduced in the samples with microspheres, whereas a char residue increased in these composites.

Tissue-Specific Microparticles Improve Organoid Microenvironment for Efficient Maturation of Pluripotent Stem-Cell-Derived Hepatocytes

Liver organoids (LOs) are receiving considerable attention for their potential use in drug screening, disease modeling, and transplantable constructs. Hepatocytes, as the key component of LOs, are isolated from the liver or differentiated from pluripotent stem cells (PSCs). PSC-derived hepatocytes are preferable because of their availability and scalability. However, efficient maturation of the PSC-derived hepatocytes towards functional units in LOs remains a challenging subject. The incorporation of cell-sized microparticles (MPs) derived from liver extracellular matrix (ECM), could provide an enriched tissue-specific microenvironment for further maturation of hepatocytes inside the LOs. In the present study, the MPs were fabricated by chemical cross-linking of a water-in-oil dispersion of digested decellularized sheep liver. These MPs were mixed with human PSC-derived hepatic endoderm, human umbilical vein endothelial cells, and mesenchymal stromal cells to produce homogenous bioengineered LOs (BLOs). This approach led to the improvement of hepatocyte-like cells in terms of gene expression and function, CYP activities, albumin secretion, and metabolism of xenobiotics. The intraperitoneal transplantation of BLOs in an acute liver injury mouse model led to an enhancement in survival rate. Furthermore, efficient hepatic maturation was demonstrated after ex ovo transplantation. In conclusion, the incorporation of cell-sized tissue-specific MPs in BLOs improved the maturation of human PSC-derived hepatocyte-like cells compared to LOs. This approach provides a versatile strategy to produce functional organoids from different tissues and offers a novel tool for biomedical applications.

Effect of Doxycycline Microencapsulation on Buccal Films: Stability, Mucoadhesion and In Vitro Drug Release

The aim of this work was to stabilize doxycycline in mucoadhesive buccal films at room temperature (25 °C). Since doxycycline is susceptible to degradation such as oxidation and epimerization, tablets are currently the only formulation that can keep the drug fully stable at room temperature, while liquid formulations are limited to refrigerated conditions (4 °C). In this study, the aim was to make formulations containing subclinical (antibiotic) doxycycline concentration that can act as matrix metalloproteinase inhibitors (MMPI) and can be stored at temperatures such as 25 °C. Here, doxycycline was complexed with excipients using three techniques and entrapped into microparticles that were stored at 4 °C, 25 °C and 40 °C. Effect of addition of precomplexed doxycycline microparticles on films: stability mucoadhesion capacity, tensile strength, swelling index and in vitro release was studied. The complexation efficiency between drug-excipients, microparticles and films was studied using Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Two of the films were found to be stable at 4 °C but the film containing microparticle composed of precomplexed doxycycline with β-cyclodextrin, MgCl₂, sodium thiosulfate, HPMC and Eudragit^® RS 12.5 was found to be stable at 25 °C until 26 weeks. The addition of microparticles to the films was found to reduce the mucoadhesive capacity, peak detachment force, tensile strength and elasticity, but improved the stability at room temperature.

Design and applications of protein delivery systems in nanomedicine and tissue engineering

Proteins are biological macromolecules involved in a wide range of biological functions, which makes them very appealing as therapeutics agents. Indeed, compared to small molecule drugs, their endogenous nature ensures their biocompatibility and biodegradability, they can be used in a large range of applications and present a higher specificity and activity. However, they suffer from unfolding, enzymatic degradation, short half-life and poor membrane permeability. To overcome such drawbacks, the development of protein delivery systems to protect, carry and deliver them in a controlled way have emerged importantly these last years. In this review, the formulation of a wide panel of protein delivery systems either in the form of polymer or inorganic nanoengineered colloids and scaffolds are presented and the protein loading and release mechanisms are addressed. A section is also dedicated to the detection of proteins and the characterization methods of their release. Then, the main protein delivery systems developed these last three years for anticancer, tissue engineering or diabetes applications are presented, as well as the major in vivo models used to test them. The last part of this review aims at presenting the perspectives of the field such as the use of protein-rich material or the sequestration of proteins. This part will also deal with less common applications and gene therapy as an indirect method to deliver protein.

Chitosan-olive oil microparticles for phenylethyl isothiocyanate delivery: Optimal formulation

Phenylethyl isothiocyanate (PEITC), a chemopreventive compound, is highly reactive due to its considerably electrophilic nature. Furthermore, it is hydrophobic and has low stability, bioavailability and bioaccessibility. This restricts its use in biomedical and nutraceutical or food applications. Thus, the encapsulation of this agent has the function of overcoming these limitations, promoting its solubility in water, and stabilizing it, preserving its bioactivity. So, polymeric microparticles were developed using chitosan-olive oil-PEITC systems. For this, an optimisation process (factors: olive oil: chitosan ratio and PEITC: chitosan ratio) was implemented through a 3-level factorial experimental design. The responses were: the particle size, zeta-potential, polydisperse index, and entrapment efficiency. The optimal formulation was further characterised by FTIR and biocompatibility in Caco-2 cells. Optimal conditions were olive oil: chitosan and PEITC: chitosan ratios of 1.46 and 0.25, respectively. These microparticles had a size of 629 nm, a zeta-potential of 32.3 mV, a polydispersity index of 0.329, and entrapment efficiency of 98.49%. We found that the inclusion process affected the optical behaviour of the PEITC, as well as the microparticles themselves and their interaction with the medium. Furthermore, the microparticles did not show cytotoxicity within the therapeutic values of PEITC. Thus, PEITC was microencapsulated with characteristics suitable for potential biomedical, nutraceutical and food applications.

Recent advances in the formulation of PLGA microparticles for controlled drug delivery

Polymeric microparticles (MPs) are recognized as very popular carriers to increase the bioavailability and bio-distribution of both lipophilic and hydrophilic drugs. Among different kinds of polymers, poly-(lactic-co-glycolic acid) (PLGA) is one of the most accepted materials for this purpose, because of its biodegradability (due to the presence of ester linkages that are degraded by hydrolysis in aqueous environments) and safety (PLGA is a Food and Drug Administration (FDA)-approved compound). Moreover, its biodegradability depends on the number of glycolide units present in the structure, indeed, lower glycol content results in an increased degradation time and conversely a higher monomer unit number results in a decreased time. Due to this feature, it is possible to design and fabricate MPs with a programmable and time-controlled drug release. Many approaches and procedures can be used to prepare MPs. The chosen fabrication methodology influences size, stability, entrapment efficiency, and MPs release kinetics. For example, lipophilic drugs as chemotherapeutic agents (doxorubicin), anti-inflammatory non-steroidal (indomethacin), and nutraceuticals (curcumin) were successfully encapsulated in MPs prepared by single emulsion technique, while water-soluble compounds, such as aptamer, peptides and proteins, involved the use of double emulsion systems to provide a hydrophilic compartment and prevent molecular degradation. The purpose of this review is to provide an overview about the preparation and characterization of drug-loaded PLGA MPs obtained by single, double emulsion and microfluidic techniques, and their current applications in the pharmaceutical industry.Graphic abstract.

In Vitro and Ex Vivo Evaluation of Penetratin as a Non-invasive Permeation Enhancer in the Penetration of Salmon Calcitonin through TR146 Buccal Cells and Porcine Buccal Tissues

Buccal tissues are considered one of the potential alternative delivery route because of fast drug absorption and onset of action due to high vascularization and a non-keratinized epithelial membrane. In this study, the effect of Penetratin on the permeation of salmon calcitonin (sCT), a model macromolecular peptide drug, through TR146 buccal cells and porcine buccal tissues has been evaluated. To observe permeation profile of sCT, TR146 buccal cells were treated with Alexa 647 conjugated sCT (Alexa 647-sCT) with different concentrations of fluorescein isothiocyanate -labeled Penetratin (FITC-Penetratin) ranging from 0 to 40 μM, and analyzed using flow cytometry and confocal laser scanning microscopy. Intracellular penetration of FITC-Penetratin rapidly increased at low concentrations from 0 to 15 μM and it gradually increased at concentrations above 15 μM. Intracellular penetration of Alexa 647-sCT enhanced with the increase of FITC-Penetratin concentration. When TR146 cell layers and buccal tissues were co-treated with sCT and Penetratin as permeation enhancer, the flux of sCT increased as per Penetratin concentration. Compared to the control, 12.2 μM of Penetratin enhanced the flux of sCT in TR146 cell layers and buccal tissues by 5.5-fold and 93.7-fold, respectively. These results strongly suggest that Penetratin may successfully act as a non-invasive permeation enhancer for macromolecular peptide drug delivery through buccal routes.

Novel biopolymer-based nanocomposite food coatings that exhibit active and smart properties due to a single type of nanoparticles

We used nanoparticles which possess simultaneously active (antimicrobial, UV-protective and antioxidant) and smart (temperature sensing) properties. The nanoparticles (2Rh = 450 nm, PDI = 0.118 ± 0.014, ζ-potential = 21 mV and T_g = 8 ± 1 °C) are based on polyethylene glycol (PEG)/methyl cellulose (MC) core with anthocyanidin and sodium acetate, and chitosan/gallotannin-based shell. The core of nanoparticles acts as a temperature indicator, changing its color from colorless into deep purple at 8 °C, while the shell provides antimicrobial (due to chitosan), UV-protective and antioxidant (due to gallotannin) effects. We incorporated these nanoparticles into the chitosan matrix. The coatings demonstrated improved mechanical and barrier properties compared with the pure chitosan coating. The elaborated coatings pronouncedly improve the shelf-life of Ricotta cheese. Moreover, they serve as thermo indicators, which warn about cheese storage at an unacceptable temperature. Thus, we developed new coatings in which all properties are enabled by a single type of nanoparticles.

Supramolecular aggregates of cyclodextrins with co-solvent modulate drug dispersion and release behavior of poorly soluble corticosteroid from chitosan membranes

In this study, the ability of different beta-cyclodextrins to facilitate homogeneous dispersion of triamcinolone acetonide (TA) into chitosan membranes is assessed. Drug loading was assessed through atomic force microscopy (AFM), scanning electron microscopy (MEV-FEG), and X-ray diffraction analyses. Drug interactions with the co-polymer were investigated with Fourier transform infrared spectroscopy, thermal analyses. Swelling assay, and in vitro drug release experiment were used to assess TA release behavior. Undispersed particles of drug were observed to remain in the simple chitosan membranes. Hydroxypropyl-β-cyclodextrin enabled the dispersion of TA into chitosan membranes and subsequent sustained drug release. In addition, the membrane performance as a drug delivery device is improved by adding specified amounts of the co-solvent triethanolamine. The experimental data presented in this study confirm the utility of our novel and alternative approach for obtaining a promising device for slow and controlled release of glucocorticoids, such as triamcinolone acetonide, for topical ulcerations.

Development and Characterization of Inkjet Printed Edible Films for Buccal Delivery of B-Complex Vitamins

Buccal films containing two vitamins, i.e., thiamine hydrochloride (THCl) and nicotinic acid (NA), were fabricated via two-dimensional (2D) inkjet printing. For the preparation of buccal films, solubility studies and rheological evaluations were conducted in distilled water and propylene-glycol (PG) as main solvent and viscosity/surface tension modifier, respectively. The increased solubility in the solvents' mixture indicated that manufacturing of several doses of the THCl and NA is achievable. Various doses were deposited onto sugar-sheet substrates, by increasing the number of printing passes. The physiochemical characterization (SEM, DSC, FTIR) revealed that inkjet printing does not affect the solid state of the matrix. Water uptake studies were conducted, to compare the different vitamin-loaded formulations. The in vitro release studies indicated the burst release of both vitamins within 10 min, a preferable feature for buccal administration. The in vitro permeation studies indicated that higher concentrations of the vitamins onto the sugar sheet improved the in vitro permeation performance of printed formulations.

Enhanced pharmacokinetic performance of dapoxetine hydrochloride via the formulation of instantly-dissolving buccal films with acidic pH modifier and hydrophilic cyclodextrin: Factorial analysis, in vitro and in vivo assessment

Instantly dissolving buccal films have gained attention owing to their easy administration and capability to surmount the hepatic first pass effect of drugs. Dapoxetine hydrochloride (DPX) has a low oral bioavailability due to significant hepatic first pass metabolism. In addition, DPX is a weakly basic drug with a pH dependent solubility that could limit its dissolution in the body neutral fluids. In order to surpass these challenges, this work aimed at enhancing DPX bioavailability via the formulation of instantly dissolving buccal films comprising a pH modifier and a hydrophilic cyclodextrin. Tartaric acid and hydroxypropyl beta-cyclodextrin were selected as dual solubilizing agents based on the screening study. 3² factorial design was employed for the formulation and optimization of DPX films. Statistical analysis revealed that hydroxypropyl methyl cellulose E5: maltodextrin ratio and propylene glycol concentrations have significant effects on mechanical properties, percent DPX dissolved after 5 min, and in vivo mouth dissolving time at P  < 0.05. The optimized film [HPMC E5: MDX, 1:1 and 1% PG] showed no significant change of properties or drug dissolution upon storage at 40 °C/75% RH for a period of 3 months. In addition, the optimized film showed significantly enhanced absorption relative to the oral reference tablet. Therefore, the optimized film could be considered a promising delivery system for DPX with expected improved patient compliance and enhanced pharmacokinetic performance.

A chitosan film containing quercetin-loaded transfersomes for treatment of secondary osteoporosis

Osteoporosis, due to its prevalence worldwide, is a serious health problem. Topical administration of quercetin, a phytoestrogen, in the form of deformable transfersomes, could be used to treat osteoporosis to overcome its low oral solubility and bioavailability. Formulation process of transfersomes was screened by fractional factorial design and further optimized using full factorial design. Transfersomes showed good characteristics such as entrapment efficiency, particle size, zeta potential, and polydispersity index (83.0 ± 2.2%, 75.95 ± 2 nm, - 13.6 ± 6 mv and 0.333, respectively). Transfersomes were further loaded into chitosan film and showed good permeation through rat skin. Further, glucocorticoid-induced osteoporosis rat model showed induction of osteoporosis after day 30. On day 45, treatment with chitosan film containing quercetin-loaded transfersomes showed remarkable rise in femur thickness, length, density as well as in serum biochemical parameters such as calcium, phosphorous, alkaline phosphatase, and tartrate-resistant alkaline phosphatase compared to positive control group. Tensile strength of osteoporotic femur bone was also found to be increased and was comparable with normal group. Histomicrographic analysis of femur bone exhibited less disruptive and lytic changes. Thus, all the above findings indicated the beneficial effects of quercetin-loaded transfersome chitosan film, due to decline in osteoclastogenesis and osteoblast apoptosis, which further favored increase in osteoblast numbers and mineralization of bones. Thus, chitosan film containing quercetin-loaded transfersomes was found to be good alternative to oral administration of quercetin to treat osteoporosis, while easy applicability of film in the form of wrist band anytime, anywhere, and even at work achieve patient compliance. Graphical abstract.

Progress in the Development of Chitosan-Based Biomaterials for Tissue Engineering and Regenerative Medicine

Over the last few decades, chitosan has become a good candidate for tissue engineering applications. Derived from chitin, chitosan is a unique natural polysaccharide with outstanding properties in line with excellent biodegradability, biocompatibility, and antimicrobial activity. Due to the presence of free amine groups in its backbone chain, chitosan could be further chemically modified to possess additional functional properties useful for the development of different biomaterials in regenerative medicine. In the current review, we will highlight the progress made in the development of chitosan-containing bioscaffolds, such as gels, sponges, films, and fibers, and their possible applications in tissue repair and regeneration, as well as the use of chitosan as a component for drug delivery applications.

Adsorption of Vi Capsular Antigen of Salmonella Typhi in Chitosan-Poly (Methacrylic Acid) Nanoparticles

The development of a nanoparticulate system for the carrier antigen is now an important tool in the vaccination process, since a smaller number of doses is necessary for effective immunization. Thus, in this work a nanoparticulate system using polymers of chitosan and poly (methacrylic acid) (CS–PMAA) to adsorb the Vi antigen of Salmonella Typhi was developed. CS–PMAA nanoparticles with different proportions of chitosan and poly (methacrylic acid) were obtained and reached sizes from 123.9 ± 2.48 to 234.9 ± 2.66 nm, and spherical shapes were seen in transmission microscopy. At pH 7.2, the nanoparticles had a cationic surface charge that contributed to the adsorption of the Vi antigen. Qualitative analyses of the isolated Vi antigen were performed using Fourier-transform infrared spectroscopy, which indicated the presence of all the characteristic bands of the capsular polysaccharide, and nuclear magnetic resonance, which showed signals for the five hydrogens and the N-acetyl and O-acetyl groups which are characteristic of the Vi antigen structure. In the adsorption kinetics study, the Vi capsular antigen, contained in a phosphate buffer solution of pH 7.2, experienced 55% adsorption on the 1–1% (CS–PMAA) nanoparticles. The adsorption kinetics results showed the ability of the nanoparticulate system to adsorb the Vi antigen.

Biocompatible Inhibitor Based on Chitosan and Amphiphilic Peptide against Mutant Huntingtin Toxicity

Huntington's disease (HD) is classified as a protein-misfolding disease correlated with the mutant Huntingtin (mHtt) protein with abnormally expanded polyglutamine (polyQ) domains. Because no effective drugs have yet been reported, attempts to develop better therapy to delay the age of onset are in urgent demand. In this study, an amphiphilic peptide consisting of negatively charged hexaglutamic acid and a stretch of decaglutamine (E₆ Q₁₀ ) was chemically synthesized as an inhibitor against polyQ and mHtt toxicity. It is found that E₆ Q₁₀ selfassembles into spherical vesicles, as shown by means of TEM, cryoelectron microscopy, and dynamic light scattering. Assembled E₆ Q₁₀ prevented the polyQ-rich peptide (KKWQ₂₀ AKK) from forming amyloid fibrils. To enable the cell-penetration ability of E₆ Q₁₀ , the E₆ Q₁₀ ⋅chitosan complex was generated. It is demonstrated that the complex penetrates cells, interferes with the mHtt oligomerization and aggregation process, and prevents mHtt cytotoxicity. By combining positively charged chitosan and amphiphilic peptides with a negatively charge moiety, a new strategy is provided to develop biocompatible and biodegradable inhibitors against mHtt toxicity.