Chitosan as Valuable Excipient for Oral and Topical Carvedilol Delivery Systems

Chitosan: An overview of biological activities, derivatives, properties, and current advancements in biomedical applications

The second and most often utilized natural polymer is chitosan (CS), a naturally existing amino polysaccharide that is produced by deacetylating chitin. Numerous applications have been the subject of in-depth investigation due to its non-hazardous, biologically compatible, and biodegradable qualities. Chitosan's characteristics, such as mucoadhesion, improved permeability, controlled release of drugs, in situ gelation process, and antibacterial activity, depend on its amino (-NH2) and hydroxyl groups (-OH). This study examines the latest findings in chitosan research, including its characteristics, derivatives, preliminary research, toxic effects, pharmaceutical kinetics and chitosan nanoparticles (CS-NPs) based for non-parenteral delivery of drugs. Chitosan and its derivatives have a wide range of physical and chemical properties that make them highly promising for use in the medicinal and pharmaceutical industries. The characteristics and biological activities of chitosan and its derivative-based nanomaterials for the delivery of drugs, therapeutic gene transfer, delivery of vaccine, engineering tissues, evaluations, and other applications in medicine are highlighted in detail in the current review. Together with the techniques for binding medications to nanoparticles, the application of the nanoparticles was also dictated by their physical properties that were classified and specified. The most recent research investigations on delivery of drugs chitosan nanoparticle-based medication delivery methods applied topically, through the skin, and through the eyes were considered.

Intranasal Delivery of Carvedilol- and Quercetin-Encapsulated Cationic Nanoliposomes for Cardiovascular Targeting: Formulation and In Vitro and Ex Vivo Studies

Carvedilol (CVD), an adrenoreceptor blocker, is a hydrophobic Biopharmaceutics Classification System class II drug with poor oral bioavailability due to which frequent dosing is essential to attain pharmacological effects. Quercetin (QC), a polyphenolic compound, is a potent natural antioxidant, but its oral dosing is restricted due to poor aqueous solubility and low oral bioavailability. To overcome the common limitations of both drugs and to attain synergistic cardioprotective effects, we formulated CVD- and QC-encapsulated cationic nanoliposomes (NLPs) in situ gel (CVD/QC-L.O.F.) for intranasal administration. We designed CVD- and QC-loaded cationic nanoliposomal (NLPs) in situ gel (CVD/QC-L.O.F.) for intranasal administration. In vitro drug release studies of CVD/QC-L.O.F. (16.25%) exhibited 18.78 ± 0.57% of QC release and 91.38 ± 0.93% of CVD release for 120 h. Ex vivo nasal permeation studies of CVD/QC-L.O.F. demonstrated better permeation of QC (within 96 h), i.e., 75.09% compared to in vitro drug release, whereas CVD permeates within 48 h, indicating the better interaction between cationic NLPs and the negatively charged biological membrane. The developed nasal gel showed a sufficient mucoadhesive property, good spreadability, higher firmness, consistency, and cohesiveness, indicating suitability for membrane application and intranasal administration. CVD-NLPs, QC-NLPs, and CVD/QC-NLPs were evaluated for in vitro cytotoxicity, in vitro ROS-induced cell viability assessment, and a cellular uptake study using H9c2 rat cardiomyocytes. The highest in vitro cellular uptake of CVD/QC-cationic NLPs by H9c2 cells implies the benefit of QC loading within the CVD nanoliposomal carrier system and gives evidence for better interaction of NLPs carrying positive charges with the negatively charged biological cells. The in vitro H2O2-induced oxidative stress cell viability assessment of H9c2 cells established the intracellular antioxidant activity and cardioprotective effect of CVD/QC-cationic NLPs with low cytotoxicity. These findings suggest the potential of cationic NLPs as a suitable drug delivery carrier for CVD and QC combination for the intranasal route in the treatment of various cardiovascular diseases like hypertension, angina pectoris, etc. and for treating neurodegenerative disorders.

Modification of physicochemical properties of chitosan to improve its pharmaceutical and agrochemical potential applications

Chitosan has received much more attention as a functional biopolymer with applications in pharmaceuticals, agricultural, drug delivery systems and cosmetics. The objectives of present investigation were to carry out modification of chitosan for enhancement of aqueous solubility, which will impart increased solubility and dissolution rate of poorly soluble drug itraconazole (ITZ) and also evaluate the modified chitosan for soyabean seed germination studies. The modification of chitosan was accomplished through the antisolvent precipitation method; employing five carboxylic acids. The resulting products were assessed for changes in molecular weight, degree of deacetylation, solubility and solid state characterization. Subsequently, the modified chitosan was complexed with itraconazole using the co-grinding technique. The prepared formulations were evaluated for solubility, FTIR (Fourier-transform infrared spectroscopy), PXRD (Powder X-ray diffraction), in-vitro dissolution studies. Furthermore the effect of modified chitosan has been evaluated on soybean seed germination. Results demonstrated that, modified chitosan improves self and solubility of itraconazole by six folds. As there was increased degree of deacetylation of chitosan leads to improvement in solubility. The results of FTIR showed the slight shifting of peaks in co-grind formulations of itraconazole. Formulations showed reduction in crystallinity of drug which leads to enhancement in dissolution rate as compared to pure itraconazole. Retention of property of seed germination was observed with modified chitosan at optimum concentration of 3 % w/v, with benefit of enhanced aqueous solubility of chitosan. This positive result paves the way for the advancement of pharmaceutical and agrochemical products employing derivatives of chitosan.

Cubosomal functionalized block copolymer platform for dual delivery of linagliptin and empagliflozin: Recent advances in synergistic strategies for maximizing control of high-risk type II diabetes

A well-made chitosan-PVP block copolymer platform was equipped with highly ordered and uniform nano-channels. This highly adhesive block copolymer platform was designed to ensure the efficient co-delivery of two synergistic-acting hypoglycemic drugs. Linagliptin oral bioavailability is 30% due to poor permeability and intestinal degradation. Its pharmacokinetics shows a non-linear profile. Empagliflozin exhibited decreased permeability and decreased solubility in aqueous media between pH 1 and 7.5. Cubosomes were functionalized as a good microdomain to guest and improve the physicochemical characteristics of drug molecules with decreased permeability and solubility. Cubosomes loaded with linagliptin (linagliptin cubosomes (LCs)) and empagliflozin (empagliflozin cubosomes ECs) were separately prepared using the top-down method and optimized by applying 23 factorial design. Optimized cubosomal systems LCs (F3) and ECs (F4) were incorporated into a chitosan-PVP gel to obtain dual cubosome-loaded platforms (LECF) optimized through 22 factorial design. The permeation study from the optimized LECF (C1) ensured enhanced empagliflozin permeation alongside continued efflux for linagliptin, resolving potential risks due to its non-linear plasma profile. The in-vivo study revealed that AUC(0-∞) of linagliptin and empagliflozin was enhanced by 2- and threefold, respectively. Therefore, the chitosan-PVP block copolymer platform buccal application for the co-delivery of linagliptin and empagliflozin could contribute to enhanced clinical effectiveness in treating diabetes.

Chitosan-Based Hydrogels for Controlled Delivery of Asiaticoside-Rich Centella asiatica Extracts with Wound Healing Potential

Centella asiatica extract is a valued plant material with known anti-inflammatory and anti-microbiological properties. Using the Design of Experiment (DoE) approach, it was possible to obtain an optimized water/alcoholic extract from Centella asiatica, which allowed the preparation of the final material with biological activity in the wound healing process. Studies on the novel applications of Centella asiatica in conjunction with the multifunctional chitosan carrier have been motivated by the plant's substantial pharmacological activity and the need to develop new and effective methods for the treatment of chronic wounds. The controlled release of asiaticoside was made possible by the use of chitosan as a carrier. Based on the findings of investigations using the PAMPA skin assay, which is a model imitating the permeability of actives through skin, this compound, characterized by sustained release from the chitosan delivery system, was identified as being well able to permeate biological membranes such as skin. Chitosan and the lyophilized extract of Centella asiatica worked synergistically to block hyaluronidase, exert efficient microbiological activity and take part in the wound healing process, as proven in an in vitro model. A formulation containing 3% extract with 3% medium-molecular-weight chitosan was indicated as a potentially new treatment with high compliance and effectiveness for patients. Optimization of the chitosan-based hydrogel preparation ensured the required rheological properties necessary for the release of the bioactive from the chitosan delivery system and demonstrated a satisfactory antimicrobial activity.

Synthesis and Characterization of Carvedilol-Etched Halloysite Nanotubes Composites with Enhanced Drug Solubility and Dissolution Rate

Carvedilol is a poorly water-soluble drug employed to treat chronic heart failure. In this study, we synthesize new carvedilol-etched halloysite nanotubes (HNTs) composites to enhance solubility and dissolution rate. The simple and feasible impregnation method is used for carvedilol loading (30-37% weight). Both the etched HNTs (acidic HCl and H₂SO₄ and alkaline NaOH treatments) and the carvedilol-loaded samples are characterized by various techniques (XRPD, FT-IR, solid-state NMR, SEM, TEM, DSC, and specific surface area). The etching and loading processes do not induce structural changes. The drug and carrier particles are in intimate contact and their morphology is preserved, as demonstrated by TEM images. The ²⁷Al and ¹³C solid-state NMR and FT-IR findings show that carvedilol interactions involve the external siloxane surface, especially the aliphatic carbons, the functional groups, and, by inductive effect, the adjacent aromatic carbons. All the carvedilol-halloysite composites display enhanced dissolution rate, wettability, and solubility, as compared to carvedilol. The best performances are obtained for the carvedilol-halloysite system based on HNTs etched with HCl 8M, which exhibits the highest value of specific surface area (91 m² g^-1). The composites make the drug dissolution independent of the environmental conditions of the gastrointestinal tract and its absorption less variable, more predictable, and independent from the pH of the medium.

Metformin Hydrochloride Mucosal Nanoparticles-Based Enteric Capsule for Prolonged Intestinal Residence Time, Improved Bioavailability, and Hypoglycemic Effect

Metformin hydrochloride enteric-coated capsule (MH-EC) is a commonly used clinical drug for the treatment of type 2 diabetes. In this study, we described a metformin hydrochloride mucosal nanoparticles enteric-coated capsule (MH-MNPs-EC) based on metformin hydrochloride chitosan mucosal nanoparticles (MH-CS MNPs) and its preparation method to improve the bioavailability and hypoglycemic effect duration of MH-EC. In intestinal adhesion study, the residue rates of free drugs and mucosal nanoparticles were 10.52% and 67.27%, respectively after cleaned with PBS buffer. MH-CS MNPs could significantly improve the efficacy of MH and promote the rehabilitation of diabetes rats. In vitro release test of MH-MNPs-EC showed continuous release over 12 h, while commercial MH-EC released completely within about 1 h in intestinal environment (pH 6.8). Pharmacokinetic study was performed in beagle dogs compared to the commercial MH-EC. The durations of blood MH concentration above 2 μg/mL were 9 h for MH-MNPs-EC versus 2 h for commercial MH-EC. The relative bioavailability of MH-MNPs-EC was determined as 185.28%, compared with commercial MH-EC. In conclusion, MH-CS MNPs have good intestinal adhesion and can significantly prolong the residence time of MH in the intestine. MH-MNPs-EC has better treatment effect compared with MH-EC, and it is expected to be a potential drug product for the treatment of diabetes because of its desired characteristics.

Development of a Self-Assembled Hydrogels Based on Carboxymethyl Chitosan and Oxidized Hyaluronic Acid Containing Tanshinone Extract Nanocrystals for Enhanced Dissolution and Acne Treatment

This study aimed to construct a pH-responsive nanocrystalline hydrogel drug delivery system for topical delivery of insoluble drugs based on the self-assembly behavior of carboxymethyl chitosan (CMC) and oxidized hyaluronic acid (OHA). The tanshinone nanocrystal (TNCs) extract was prepared by dielectric milling method, the type and ratio of stabilizer of the drug were investigated to optimize the prescription, and the effector surface method was used to optimize the preparation process. OHA was prepared by the sodium periodate oxidation method, and the concentration of CMC and OHA was optimized using gel formation time as an indicator. OHA was dissolved in TNCs and self-assembled with CMC solution to form tanshinone extract nanocrystal hydrogels (CMC-OHA/TNCs), of which the physicochemical properties and in vitro antibacterial activity were evaluated. Results showed that the optimized prescription and process could produce tanshinone extract nanocrystals with a particle size of (223.67 ± 4.03) nm and a polydispersity index (PDI) of 0.2173 ± 0.0008. According to SEM and XRD results, TNCs were completely wrapped in the hydrogel as nanoparticles, and the crystallinity of TNCs was reduced and the diffraction peaks in CMC-OHA/TNCs almost disappeared. In vitro, transdermal test results showed that CMC-OHA/TNCs could release the drug continuously at the acne lesions. The cell-counting kit-8 (CCK-8) assay confirmed that the CMC-OHA/TNCs had no obvious cytotoxicity. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CMC-OHA/TNCs against Propionibacterium acnes and Staphylococcus aureus were significantly lower and the diameter of the inhibition circle was obviously higher than that of TNCs and tanshinone extract crude suspension. This study demonstrated that CMC-OHA/TNCs was a promising delivery system for topical delivery of insoluble drugs, which could improve the solubility of tanshinone extract and enhance its in vitro bacterial inhibitory activity.

Solubilization and Controlled Release Strategy of Poorly Water-Soluble Drugs

The processes of solubilization and controlled release of drugs that are poorly soluble in water are highly relevant in drug preformulation studies in pharmaceutical development [...]

Chitosan as a Functional Carrier for the Local Delivery Anti-Inflammatory Systems Containing Scutellariae baicalensis radix Extract

The aim of the study was to establish the influence of chitosan on the preparation of systems containing Scutellariae baicalensis radix extract and to demonstrate the potential of anti-inflammatory action for the treatment of periodontitis. In the first stage, the impact of the variables (extraction mixture composition, temperature, and the number of extraction cycles) on the extracted samples' biological characteristics was analyzed using the Design of Experiments (DoE) approach. The best conditions for baicalin, baicalein, and wogonin extraction from Scutellariae baicalensis radix were 80% methanol in the extraction mixture, 70 °C, and 4 cycles per 60 min. The DoE approach can be used to choose the best chitosan system parameters with equal success. An increase in the deacetylation degree of chitosan used in the system improved the potential for reducing free radicals and inhibiting the hyaluronidase enzyme. Also, increasing the degree of chitosan deacetylation results in increased resistance of the carrier to biodegradation and an extended baicalin release profile, which is also associated with an increase in the viscosity of the chitosan-based system. In total, the system of a freeze-dried extract with chitosan 90/500 in the ratio of 2:1 (system S9) turns out to be the one with the best physicochemical (high percentage of baicalin release and the highest viscosity conditioning the prolonged stay at the site of administration) and biological properties (the highest antioxidant and anti-inflammatory activities), resulting in the highest potential for use in the treatment of oral inflammatory diseases.

Architecting novel multilayer nanosponges for co-administration of two drugs managing high-risk type II diabetes mellitus patients suffering from cardiovascular diseases

Nanosponges are porous solid nanoparticles composed of hyper-cross-linked polymers that serve as specific micro-domains designed for the co-encapsulation of two drugs with different chemical structures. Our goal was to engineer a novel assembly of multilayer nanosponges (MLNS) based on a layer-by-layer approach. This MLNS was engineered to incorporate two drugs (linagliptin and empagliflozin) in a new drug delivery route. Linagliptin has a low oral bioavailability due to intestinal degradation and low permeability. Its pharmacokinetics shows a non-linear profile which leads to a disproportionate increase in its effectiveness with increasing the dose frequency. Empagliflozin has a low permeability and is very slightly soluble in aqueous media between pH 1-7.5. MLNS could improve their bioavailability along with resolving possible risks due to the non-linear pharmacokinetics of linagliptin and maximizing its dose efficiency. 2³ factorial design was used to optimize the novel systems. MLNS (F4) was chosen as the optimal system with an average diameter of 40 nm and the highest entrapment efficiency which accounts for 92.93 % ± 2.27 and 100.94 % ± 0.55 for linagliptin and empagliflozin respectively. Förster resonance energy transfer confirmed the formation of a multilayer structure in MLNS. The optimized system was incorporated within chitosan mucoadhesive buccal films which were optimized through 2²factorial design. The permeation study from optimized MLNS-film (B4) ensured an improved empagliflozin permeation along with a controlled efflux for linagliptin, resolving possible risks due to the nonlinear plasma profile. The in-vivo study of MLNS-film (B4) revealed that AUC_(0-∞)of linagliptin and empagliflozin was enhanced by two-fold and ten-fold, respectively. Therefore, the nano-buccal formulation for the co-delivered hypoglycemic drugs could contribute to improved clinical efficacy in the treatment of diabetes.

Progress in Research of Chitosan Chemical Modification Technologies and Their Applications

Chitosan, which is derived from chitin, is the only known natural alkaline cationic polymer. Chitosan is a biological material that can significantly improve the living standard of the country. It has excellent properties such as good biodegradability, biocompatibility, and cell affinity, and has excellent biological activities such as antibacterial, antioxidant, and hemostasis. In recent years, the demand has increased significantly in many fields and has huge application potential. Due to the poor water solubility of chitosan, its wide application is limited. However, chemical modification of the chitosan matrix structure can improve its solubility and biological activity, thereby expanding its application range. The review covers the period from 1996 to 2022 and was elaborated by searching Google Scholar, PubMed, Elsevier, ACS publications, MDPI, Web of Science, Springer, and other databases. The various chemical modification methods of chitosan and its main activities and application research progress were reviewed. In general, the modification of chitosan and the application of its derivatives have had great progress, such as various reactions, optimization of conditions, new synthetic routes, and synthesis of various novel multifunctional chitosan derivatives. The chemical properties of modified chitosan are usually better than those of unmodified chitosan, so chitosan derivatives have been widely used and have more promising prospects. This paper aims to explore the latest progress in chitosan chemical modification technologies and analyze the application of chitosan and its derivatives in various fields, including pharmaceuticals and textiles, thus providing a basis for further development and utilization of chitosan.

The Chitosan-Based System with Scutellariae baicalensis radix Extract for the Local Treatment of Vaginal Infections

Scutellarie baicalensis radix, as a flavone-rich source, exhibits antibacterial, antifungal, antioxidant, and anti-inflammatory activity. It may be used as a therapeutic agent to treat various diseases, including vaginal infections. In this study, six binary mixtures of chitosan with stable S. baicalensis radix lyophilized extract were obtained and identified by spectral (ATR-FTIR, XRPD) and thermal (TG and DSC) methods. The changes in dissolution rates of active compounds and the significant increase in the biological properties towards metal chelating activity were observed, as well as the inhibition of hyaluronic acid degradation after mixing plant extract with chitosan. Moreover, the combination of S. baicalensis radix lyophilized extract with a carrier allowed us to obtain the binary systems with a higher antifungal activity than the pure extract, which may be effective in developing new strategies in the vaginal infections treatment, particularly vulvovaginal candidiasis.

Amorphous Form of Carvedilol Phosphate-The Case of Divergent Properties

The amorphous form of carvedilol phosphate (CVD) was obtained as a result of grinding. The identity of the obtained amorphous form was confirmed by powder X-ray diffraction (PXRD), different scanning calorimetry (DSC), and FT-IR spectroscopy. The process was optimized in order to obtain the appropriate efficiency and time. The crystalline form of CVD was used as the reference standard. Solid dispersions of crystalline and amorphous CVD forms with hydrophilic polymers (hydroxypropyl-β-cyclodextrin, Pluronic^® F-127, and Soluplus^®) were obtained. Their solubility at pH 1.2 and 6.8 was carried out, as well as their permeation through a model system of biological membranes suitable for the gastrointestinal tract (PAMPA-GIT) was established. The influence of selected polymers on CVD properties was defined for the amorphous form regarding the crystalline form of CVD. As a result of grinding (four milling cycles lasting 15 min with 5 min breaks), amorphous CVD was obtained. Its presence was confirmed by the “halo effect” on the diffraction patterns, the disappearance of the peak at 160.5 °C in the thermograms, and the changes in position/disappearance of many characteristic bands on the FT-IR spectra. As a result of changes in the CVD structure, its lower solubility at pH 1.2 and pH 6.8 was noted. While the amorphous dispersions of CVD, especially with Pluronic^® F-127, achieved better solubility than combinations of crystalline forms with excipients. Using the PAMPA-GIT model, amorphous CVD was assessed as high permeable (Papp > 1 × 10⁻⁶ cm/s), similarly with its amorphous dispersions with excipients (hydroxypropyl-β-cyclodextrin, Pluronic^® F-127, and Soluplus^®), although in their cases, the values of apparent constants permeability were decreased.