Engineering drug delivery systems to overcome the vaginal mucosal barrier: Current understanding and research agenda of mucoadhesive formulations of vaginal delivery

Chitosan decorated oleosomes loaded propranolol hydrochloride hydrogel repurposed for Candida albicans-vaginal infection

Aim: Our investigation aims to estimate the antifungal effect of propranolol hydrochloride (PNL). Methods: Oleosomes (OLs) were fabricated by thin-film hydration and evaluated for entrapment efficiency (EE%), particle size (PS), polydispersity index (PDI), zeta potential (ZP), and amount of drug released after 6 h Q6h (%). Results: The optimal OL showed a rounded shape with optimum characteristics. The ex-vivo permeation and confocal laser scanning microscopy verified the prolonged release and well deposition of PNL-loaded OLs-gel. The in-silico assessment demonstrated the good stability of PNL with OLs' ingredients. In vivo evaluations for PNL-loaded OLs-gel showed a good antifungal impact against Candida albicans with good safety. Conclusion: This work highlights the potential of PNL-loaded OLs-gel as a potential treatment for candida vaginal infection.

Transmucosal Delivery of Peptides and Proteins Through Nanofibers: Current Status and Emerging Developments

Advancements in recombinant DNA technology have made proteins and peptides available for diagnostic and therapeutic applications, but their effectiveness when taken orally leads to poor patient compliance, requiring clinical administration. Among the alternative routes, transmucosal delivery has the advantage of being noninvasive and bypassing hepato-gastrointestinal clearance. Various mucosal routes-buccal, nasal, pulmonary, rectal, and vaginal-have been explored for delivering these macromolecules. Nanofibers, due to their unique properties like high surface-area-to-volume ratio, mechanical strength, and improved encapsulation efficiency, serve as promising carriers for proteins and peptides. These nanofibers can be tailored for quick dissolution, controlled release, enhanced encapsulation, targeted delivery, and improved bioavailability, offering superior pharmaceutical and pharmacokinetic performance compared to conventional methods. This leads to reduced dosages, fewer side effects, and enhanced patient compliance. Hence, nanofibers hold tremendous potential for protein/peptide delivery, especially through mucosal routes. This review focuses on the therapeutic application of proteins and peptides, challenges faced in their conventional delivery, techniques for fabricating different types of nanofibers and, various nanofiber-based dosage forms, and factors influencing nanofiber generation. Insights pertaining to the precise selection of materials used for fabricating nanofibers and regulatory aspects have been covered. Case studies wherein the use of specific protein/peptide-loaded nanofibers and delivered via oral/vaginal/nasal mucosa for diagnostic/therapeutic use and related preclinical and clinical studies conducted have been included in this review.

A novel electrospun nanofiber system with PEGylated paclitaxel nanocrystals enhancing the transmucus permeability and in situ retention for an efficient cervicovaginal cancer therapy

Overcoming the vaginal barrier to achieve sufficient drug penetration and retention is a huge obstacle for drug delivery in chemotherapeutics for cervical cancer. In this study, we investigate the feasibility of a novel composite nanocrystal/nanofiber system for improving the transmucus penetration and, thus, enhancing retention and drug delivery to the lesion of a cervicovaginal tumor. Herein, paclitaxel (PTX) was sequentially formulated in the form of nanocrystals, coated with polydopamine (PDA), and modified with PEG. The nanocrystals (NCs@PDA-PEG) were creatively fabricated to create a composite nanofibrous membrane (NCs@PDA-PEG NFs) by using an electrospinning technique. The morphology, size distribution, drug loading, encapsulation efficiency, X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectra, in vitro release, in vivo vaginal retention, apoptosis index, anti-tumor efficacy in a murine cervicovaginal tumor model, and local irritation were characterized. The NCs@PDA-PEG were formulated in a cube-like shape with an average size of 385.6 ± 35.47 nm; they were dispersed in electrospun nanofibers, and the drug loading was 7.94 %. The XRD curves indicated that the phase state of PTX changed after the creation of the nanocrystals. The FTIR spectra showed that the drug and the excipients were compatible with each other. In vitro delivery showed that the dissolution of PTX in the electrospun nanofibers was significantly faster than that when using bulk PTX. Compared with the PTX NC NFs, the NC@PDA-PEG NFs exhibited prolonged vaginal residence, superior transmucus penetration, minimal mucosal irritation, and significant tumor inhibition efficacy after the intravaginal administration of the NFs in tumor-bearing mice. In conclusion, by acting as novel pharmaceutical repositories, NCs@PDA-PEG NFs can be promising candidates for non-invasive local treatment, leading to efficient tumor inhibition in cervicovaginal cancer.

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.

Nano-Econazole Enhanced PD-L1 Checkpoint Blockade for Synergistic Antitumor Immunotherapy against Pancreatic Ductal Adenocarcinoma

Insufficienct T lymphocyte infiltration and unresponsiveness to immune checkpoint blockade therapy are still major difficulties for the clinical treatment of pancreatic ductal adenocarcinoma (PDAC). Although econazole has shown promise in inhibiting PDAC growth, its poor bioavailability and water solubility limit its potential as a clinical therapy for PDAC. Furthermore, the synergistic role of econazole and biliverdin in immune checkpoint blockade therapy in PDAC remains elusive and challenging. Herein, a chemo-phototherapy nanoplatform is designed by which econazole and biliverdin can be co-assembled (defined as FBE NPs), which significantly improve the poor water solubility of econazole and enhance the efficacy of PD-L1 checkpoint blockade therapy against PDAC. Mechanistically, econazole and biliverdin are directly released into the acidic cancer microenvironment, to activate immunogenic cell death via biliverdin-induced PTT/PDT and boost the immunotherapeutic response of PD-L1 blockade. In addition, econazole simultaneously enhances PD-L1 expression to sensitize anti-PD-L1 therapy, leading to suppression of distant tumors, long-term immune memory effects, improved dendritic cell maturation, and tumor infiltration of CD8⁺ T lymphocytes. The combined FBE NPs and α-PDL1 show synergistic antitumor efficacy. Collectively, FBE NPs show excellent biosafety and antitumor efficacy by combining chemo-phototherapy with PD-L1 blockade, which has promising potential in a precision medicine approach as a PDAC treatment strategy.

Preparation and Evaluation of Modified Chitosan Nanoparticles Using Anionic Sodium Alginate Polymer for Treatment of Ocular Disease

Mucoadhesive nanoparticles offer prolonged drug residence time at the corneal epithelium by adhering to the mucous layer of the eye. Here, in this research investigation, voriconazole-loaded chitosan mucoadhesive nanoparticles (VCZ-MA-NPs) were modified to mucous-penetrating nanoparticles (VCZ-MP-NPs) by coating them with anionic polymer sodium alginate. The ionic gelation method was utilized to prepare mucoadhesive chitosan nanoparticles, which were further coated with sodium alginate to obtain the surface properties essential for mucous penetration. The developed VCZ-MA-NPs and VCZ-MP-NPs were evaluated extensively for physicochemical delineation, as well as in vitro and ex vivo studies. The particle size, polydispersity index, and ζ potential of the VCZ-MA-NPs were discovered to be 116 ± 2 nm, 0.23 ± 0.004, and +16.3 ± 0.9 mV, while the equivalent values for VCZ-MP-NPs were 185 ± 1 nm, 0.20 ± 0.01, and -24 ± 0.9 mV, respectively. The entrapment efficiency and drug loading were obtained as 88.06%±1.29% and 7.27% ± 0.95% for VCZ-MA-NPs and 91.31% ± 1.05% and 10.38% ± 0.87% for VCZ-MP-NPs, respectively. The formulations were found to be stable under different conditions (4 °C, 25 °C, and 40 °C). Chitosan nanoparticles and modified nanoparticles showed a spherical and smooth morphology under electron microscopic imaging. An excised caprine cornea was used for the ex vivo permeation study, exhibiting 58.98% ± 0.54% and 70.02% ± 0.61% drug permeation for VCZ-MA-NPs and VCZ-MP-NPs, respectively. The findings revealed that the mucous-penetrating nanoparticles could effectively pass through the corneal epithelium, thus overcoming the mucous barrier and fungal layer of the eye, which highlights their potential in the treatment of fungal keratitis.

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.