Current trends in chitosan based nanopharmaceuticals for topical vaginal therapies

Chitosan and liposomal delivery systems for epicatechin or propyl gallate targeting localized treatment of vulvovaginal candidiasis

Natural polyphenols are promising alternatives to antifungals for novel treatments of vulvovaginal candidiasis (VVC) in an era of antimicrobial resistance. However, polyphenols are poorly soluble and prone to degradation. To overcome their limitations, we propose incorporation in liposomes. The study aimed to develop chitosan and liposome comprising delivery systems for epicatechin (EC) or propyl gallate (PG) as treatment of VVC. EC was selected for its antioxidative properties and PG as an ester of antifungal gallic acid. To improve formulation retention at vaginal site, mucoadhesive chitosan was introduced into formulation as liposomal surface coating or hydrogel due to intrinsic antifungal properties. These polyphenol-loaded liposomes exhibited an average size of 125 nm with a 64 % entrapment efficiency (for both polyphenols). A sustained in vitro polyphenol release was seen from liposomes, particularly in chitosan hydrogel (p < 0.01 or lower). Viscosity was evaluated since increased viscosity upon mucin contact indicated adhesive bond formation between chitosan and mucin confirming mucoadhesiveness of formulations. Antifungal activity was evaluated by the broth microdilution method on Candida albicans CRM-10231. Unlike PG, incorporation of EC in liposomes enabled antifungal activity. Fungicidal activity of chitosan was confirmed both when used as liposomal coating material and as hydrogel vehicle.

Metronidazole loaded chitosan-phytic acid polyelectrolyte complex nanoparticles as mucoadhesive vaginal delivery system for bacterial vaginosis

Bacterial vaginosis (BV) is a recurring infection that is difficult to treat due to the limited bioavailability of antimicrobials. In this study, Metronidazole (MTZ)-loaded chitosan nanoparticles (MCSNP) were synthesized employing phytic acid (PA) as a crosslinking agent for treating bacterial vaginosis. The prepared MCSNPs were characterized for size, shape, surface charge, compatibility, cytotoxicity, biofilm inhibition, and in-vitro/in-vivo antimicrobial activities. Morphological examination revealed that nanoparticles generated from 0.535 % w/v chitosan and 0.112 % w/v PA were non-spherical, discontinuous, and irregular, with zeta potential ranging from 25.00 ± 0.45 to 39 ± 0.7. The results of DSC and XRD demonstrated no change in the physical state of the drug in the finished formulation. The optimized formulation demonstrates a cumulative drug release of about 98 ± 1.5 % within 8 h. Antimicrobial studies demonstrated that the optimized formulation had enhanced efficacy against acid-adapted BV pathogens, with a MIC value of 0.9 ± 0.1 μg/mL. Compared to the MTZ alone, the in-vivo antibacterial results of in the case of developed nanoparticles showed a four-fold reduction in bacterial count in female Swiss albino mice. Based on the experimental findings, it was concluded that MCSNPs, due to their excellent physiochemical and antibacterial properties, could serve as a potential topical alternative for treating BV.

Design and evaluation of antibacterials crosslinked chitosan nanoparticle as a novel carrier for the delivery of metronidazole to treat bacterial vaginosis

Bacterial vaginosis (BV) is a recurring, chronic infection that is difficult to treat due to the limited bioavailability of antimicrobials within vaginal epithelial cells. Vaginal administration, because of lower dosing and systemic exposure offers a viable option for treating vaginal infections. In this study, Metronidazole-loaded chitosan nanoparticles were synthesised employing borax (BX) or tannic acid (TA) as an antimicrobial crosslinking agent for treating BV. The prepared NPs were characterized for various physical, physicochemical, pharmaceutical, thermal and antibacterial properties. Morphological investigation revealed that nanoparticles prepared from 0.5 % w/v chitosan, 1.2 % w/v BX, and 0.4 % w/v metronidazole (MTZ) were non-spherical, with particle sizes of 377.4 ± 37.3 nm and a zeta potential of 34 ± 2.1 mV. The optimised formulation has MIC values of 24 ± 0.5 and 59 ± 0.5 μg/mL, against Escherichia coli (E.coli) and Candida albicans (C.albicans) respectively. The results of DSC and XRD demonstrated no change in the physical state of the drug in the finished formulation. Under simulated vaginal fluid, the optimised formulation demonstrates a cumulative drug release of about 90 % within 6h. The prepared borax crosslinked NPs exhibit anti-fungal activities by inhibiting ergosterol synthesis. The in-vivo antibacterial data indicated a comparable reduction in bacterial count compared to the marketed formulation in female Swiss albino mice treated with optimised nanoparticles. According to histopathological findings, the prepared nanoparticle was safe for vaginal use. Based on the experimental findings, it was concluded that MBCSNPs, due to their good physiochemical and antimicrobial properties, could serve as a potential topical alternative for treating BV and reducing fungal infection.

Chitosan-coated miconazole as an effective anti-inflammatory agent for the treatment of postoperative infections in obstetrics and vaginal yeast infection control on in vitro evaluations

People with immune deficiency are at risk of developing infections caused by several bacterial and fungal species. In this work, chitosan-coated miconazole was developed by a simple sol-gel method. Miconazole is considered an effective drug to treat vaginal infection-causing bacteria and fungi. The coating of chitosan with miconazole nitrate showed the highest drug loading efficiency (62.43%) and mean particle size (2 μm). FTIR spectroscopic analysis confirmed the entrapment of miconazole nitrate into chitosan polymer. The antifungal result demonstrated that MN@CS microgel possessed notable anti-Aspergillus fumigatus and Candida albicans activity in lower doses. Antibacterial activity results revealed excellent bacterial growth inhibition of MN@CS microgel towards human skin infectious pathogens Escherichia coli and Staphylococcus aureus. The biocompatibility studies of In vitro cell viability and Artemia salina lethality assay suggested that MN@CS microgel is more biosafe and suitable for human external applications. In the future, it will be an efficient anti-inflammatory agent for the treatment of vaginal infections.

Enhanced Anti-Herpetic Activity of Valacyclovir Loaded in Sulfobutyl-ether-β-cyclodextrin-decorated Chitosan Nanodroplets

Valacyclovir (VACV) was developed as a prodrug of the most common anti-herpetic drug Acyclovir (ACV), aiming to enhance its bioavailability. Nevertheless, prolonged VACV oral treatment may lead to the development of important side effects. Nanotechnology-based formulations for vaginal administration represent a promising approach to increase the concentration of the drug at the site of infection, limiting systemic drug exposure and reducing systemic toxicity. In this study, VACV-loaded nanodroplet (ND) formulations, optimized for vaginal delivery, were designed. Cell-based assays were then carried out to evaluate the antiviral activity of VACV loaded in the ND system. The chitosan-shelled ND exhibited an average diameter of about 400 nm and a VACV encapsulation efficiency of approximately 91% and was characterized by a prolonged and sustained release of VACV. Moreover, a modification of chitosan shell with an anionic cyclodextrin, sulfobutyl ether β-cyclodextrin (SBEβCD), as a physical cross-linker, increased the stability and mucoadhesion capability of the nanosystem. Biological experiments showed that SBEβCD-chitosan NDs enhanced VACV antiviral activity against the herpes simplex viruses type 1 and 2, most likely due to the long-term controlled release of VACV loaded in the ND and an improved delivery of the drug in sub-cellular compartments.

Nanoparticle Synthesis and Their Integration into Polymer-Based Fibers for Biomedical Applications

The potential of nanoparticles as effective drug delivery systems combined with the versatility of fibers has led to the development of new and improved strategies to help in the diagnosis and treatment of diseases. Nanoparticles have extraordinary characteristics that are helpful in several applications, including wound dressings, microbial balance approaches, tissue regeneration, and cancer treatment. Owing to their large surface area, tailor-ability, and persistent diameter, fibers are also used for wound dressings, tissue engineering, controlled drug delivery, and protective clothing. The combination of nanoparticles with fibers has the power to generate delivery systems that have enhanced performance over the individual architectures. This review aims at illustrating the main possibilities and trends of fibers functionalized with nanoparticles, focusing on inorganic and organic nanoparticles and polymer-based fibers. Emphasis on the recent progress in the fabrication procedures of several types of nanoparticles and in the description of the most used polymers to produce fibers has been undertaken, along with the bioactivity of such alliances in several biomedical applications. To finish, future perspectives of nanoparticles incorporated within polymer-based fibers for clinical use are presented and discussed, thus showcasing relevant paths to follow for enhanced success in the field.

Biomaterials science and engineering to address unmet needs in women's health

Medical conditions that primarily or disproportionately affect women have historically been poorly studied. In contrast to the musculoskeletal and cardiovascular systems, there is no lengthy record of biomaterials research addressing women's health needs. In this article, the historical reasons for this discrepancy are examined. The anatomy of both the nonpregnant and pregnant reproductive tissues is reviewed, including the ovaries, uterus, and (fetal) placenta. Examples of biomaterials-related women's health research are described, including tissue engineering, organoids, and microphysiological systems. The future of the field is considered with dual focuses. First, there is a significant need for novel approaches to advance women's health through materials and biomaterials, particularly in complex biomimetic hydrogels. Second, there is an exciting opportunity to enlarge the community of biomaterials scientists and engineers working in women's health to encourage more contributions to its rapidly emerging product development pipeline.

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.

Overexpression and Biochemical Properties of a GH46 Chitosanase From Marine Streptomyces hygroscopicus R1 Suitable for Chitosan Oligosaccharides Preparation

Due to the various biological activities of chitosan oligosaccharides (COSs), they have great potential value for use in many areas. Chitosanase plays an important role in enzymatic preparation of COSs. Herein, a gene encoding a chitosanase (ShCsn46) from marine Streptomyces hygroscopicus R1 was cloned and the sequences encoding ShCsn46 without signal peptide were optimized based on the codon usage of Pichia pastoris (P. pastoris). In addition, the optimized gene was ligated to pPICZαA and transformed to P. pastoris X33. After screening, a recombinant strain named X33-Sh33 with the highest activity was isolated from 96 recombinant colonies. The maximum activity and total protein concentration of the recombinant strain ShCsn46 were 2250 U/ml and 3.98 g/l, respectively. The optimal pH and temperature of purified ShCsn46 were 5.5 and 55°C, respectively. Meanwhile, ShCsn46 was stable from pH 5.0 to 10.0 and 40 to 55°C, respectively. The purified ShCsn46 was activated by Mn²⁺ and inhibited by Cu²⁺, Fe²⁺, and Al³⁺. In addition, substrate specificity of the purified ShCsn46 showed highest activity toward colloidal chitosan with 95% degree of deacetylation. Furthermore, the purified ShCsn46 exhibited high efficiency to hydrolyze 4% colloidal chitosan to prepare COSs. COSs with degree of polymerization of 2–6, 2–5, and 2–4 were controllably produced by adjusting the reaction time. This study provides an excellent chitosanase for the controllable preparation of COSs with a desirable degree of polymerization.