Transethosomes: Cutting edge approach for drug permeation enhancement in transdermal drug delivery system

The skin is a major route of drug administration. Despite the high surface area of the skin, drug delivery via the skin route is problematic due to its physiological obstacles. The formulation scientist has developed a vesicular system to enhance the skin's absorption of bioactive substances. Among numerous vesicular systems, concept of transethosomes (TEs) introduced in 2012 are being tested for drug delivery to the dermis. When transferosomes and ethosomes interact, TEs are produced. It consists of water, ethanol, phospholipids, and an edge activator. Ethanol and the edge activator increase the absorption of medication through the skin. In the presence of ethanol and an edge activator, skin permeability can increase. The advantages of TEs include increased patient compliance, bypassing first-pass metabolism, including non-toxic raw components, being a noninvasive method of drug delivery, being more stable, biocompatible, biodegradable, and administered in semisolid form. TEs can be produced through the use of hot, cold, mechanical dispersion, and conventional techniques. The morphology, shape, size, zeta potential, drug loading efficiency, vesicle yield, biophysical interactions, and stability of TEs define them. Recent studies reported successful transdermal distribution of antifungal, antiviral, anti-inflammatory, and cardiovascular bioactive while using ethosomes with significant deeper penetration in skin. The review extensively discussed various claims on TEs developed by researchers, patents, and marketed ethosomes. However, till today no patens being granted on TEs. There are still lingering difficulties related to ethanol-based TEs that require substantial research to fix.

A chitosan-based nanosystem as pneumococcal vaccine delivery platform

Chitosan-based nanosystems have been described as interesting tools for antigen delivery and for enhancing the immunogenicity of nasally administered vaccines. As a possible vaccine delivery method, the chemical conjugation of chitosan nanocapsules with the Streptococcus pneumoniae cell membrane protein PsaA (pneumococcal surface adhesin A) is suggested here. The antigen PsaA, common to all pneumococcus serotypes, is expected to improve its uptake by immune cells and to activate specific T cells, generating an adaptive immune response against pneumococcus. With this aim, chitosan nanocapsules with thiol-maleimide conjugation between the polymer (chitosan) and the antigen (PsaA) were designed to enable the surface presentation of PsaA for immune cell recognition. Spherical-shaped particles, with a size of 266 ± 32 nm, positive charge of +30 ± 1 mV, and good stability profiles in simulated nasal fluids (up to 24 h) were achieved. PsaA association rates were three times higher compared with nanocapsules without covalent polymer-protein conjugation. Cytotoxicity studies in cell culture media showed non-toxic effect under 150 µg/mL concentration of nanocapsules, and subsequent studies on the maturation of immature dendritic cells in the presence of antigen-conjugated nanocapsules displayed peripheral blood mononuclear cell activation and lymphocyte differentiation after their presentation by dendritic cells. Secretion of TNFα following exposure to nanocapsules and the ability of nanocapsules to activate CD4 and CD8 T lymphocytes had also been studied. Antigen loaded nanocarrier uptake and presentation by professional presenting cells.

BCG-loaded chitosan microparticles: interaction with macrophages and preliminary in vivo studies

The aim of this study was to develop a novel BCG-loaded chitosan vaccine with high association efficiency which can afford efficient interaction with APC and elicit local and Th1-type-specific immune response after intranasal administration. Chitosan-suspended BCG and BCG-loaded chitosan-alginate microparticles were prepared by ionotropic gelation. Interaction with APC was evaluated by fluorescence microscopy using rBCG-GFP. Specific immune responses were evaluated following intranasal immunisation of mice. Cellular uptake was approximately two-fold higher for chitosan-suspended BCG. A single dose of BCG-loaded microparticles or chitosan-suspended BCG by intranasal route improved Th1-type response compared with subcutaneous BCG. Chitosan-suspended BCG originated the highest mucosal response in the lungs by intranasal route. These positive results indicate that the proposed approach of whole live BCG microencapsulation in chitosan-alginate for intranasal immunisation was successful in allowing efficient interaction with APC, while improving the cellular immune response, which is of interest for local immunisation against tuberculosis.

Ufasomes nano-vesicles-based lyophilized platforms for intranasal delivery of cinnarizine: preparation, optimization, ex-vivo histopathological safety assessment and mucosal confocal imaging

To circumvent the low and erratic absorption of orally administrated cinnarizine (CN), intranasal lyophilized gels containing unsaturated fatty acid liposomes (ufasomes) and encapsulating CN were prepared from oleic acid using a simple assembling strategy. The effects of varying drug concentration and cholesterol percentage on ufasomes size, polydispersity index and entrapment efficiency were investigated using 3(1)4(1) full factorial design. The optimized ufasomes that contained 14% cholesterol relative to oleic acid displayed spherical morphology with average size of 788 nm and entrapment efficiency of 80.49%. To overcome the colloidal instability of CN-loaded ufasomes dispersions and their short residence time in the nasal cavity, the ufasomes were incorporated into mucoadhesive hydrogels that were lyophilized into unit dosage forms for accurate dosing. Scanning electron micrographs of the lyophilized gel revealed that the included ufasomes were intact, non-aggregating and maintained their spherical morphology. Rheological characterization of reconstituted ufasomal lyophilized gel ensured ease of application. Furthermore, the gel induced minor histopathological alterations in sheeps' nasal mucosa. Ex-vivo confocal laser imaging confirmed the ability of ufasomes to penetrate deep through nasal mucosa layers. The results highlighted in the current work confirm the feasibility of using CN-loaded ufasomal gels for intranasal drug delivery.