Chitosan-based buccal mucoadhesive patches to enhance the systemic bioavailability of tizanidine.

Tizanidine hydrochloride (TZN) is a muscle relaxant used to treat a variety of disorders such as painful muscle spasms and chronic spasticity. TZN has low oral bioavailability due to extensive first-pass metabolism and is used orally at a dose of 6-24 mg per day. In the present study, buccal patches were prepared by solvent casting method using chitosan glutamate (Chi-Glu) and novel chitosan azelate (Chi-Aze) which was synthesised in-house for the first time, to enhance the bioavailability of TZN by bypassing first-pass metabolism. The characterisation, mucoadhesion and drug release studies were performed. Chi-Aze patches retained their integrity longer in the buccal medium and showed higher ex vivo drug permeability compared to that prepared with Chi-Glu. In vivo studies revealed that buccal formulation fabricated with Chi-Aze (3%) showed approx 3 times more bioavailability than the orally administered commercial product. Results of the studies indicate that Chi-Aze, prepared by conjugation of chitosan and a fatty acid, the patch formulation is a promising buccal mucoadhesive system due to the physical stability in buccal medium, the good mucoadhesiveness and the high TZN bioavailability. Moreover, Chi-Aze patch might be an alternative to oral formulations of TZN to reduce the dose and frequency of drug administration.

Relationship between phosphorylamine-modification and molecular weight on transfection efficiency of chitosan.

The aim of this study is both to design the chitosan (Chi) nanoparticles with different Mw containing the phosphoester bonds and increase their amino function for the transfection. The phosphorylamine-modification of Chi and depolymerized Chi (DChi) was realized using o-phosphorylethanolamine (o-PEA) and characterized, for the first time. The nanoparticles (nMChi and nMDChi) were prepared by ionic gelation and their particle size, polydispersity index (PDI), zeta potential, stability, gene binding capacity and cytotoxicity were examined. The effects of the Mw of Chi on the cytotoxicity, gene binding capacity, and in vitro transfection efficiency of the nanoparticles on Human Embryonic Kidney 293 (HEK293) cells were also examined. Green Fluorescent Protein Circular Plasmid DNA (pEGFN1) loaded nanoparticles (gnMChi and gnMDChi) were used in the transfection. This study showed that the Mw of phosphorylamine-modified Chi significantly affected the characteristics, cytotoxicity, gene binding capacity and transfection efficiency of the nanoparticles.

Modified chitosan-based nanoadjuvants enhance immunogenicity of protein antigens after mucosal vaccination.

Nasal vaccination is considered to be an effective and convenient way of increasing immune responses both systemically and locally. Although various nanovaccine carriers have been introduced as potential immune adjuvants, further improvements are still needed before they can be taken to clinical usage. Chitosan-based nanovaccine carriers are one of the most widely studiedadjuvants, owing to the abilityof chitosan toopen tight junctions between nasal epithelial cells and enhance particle uptake as well as its inherent immune activating role. In present study, bovine serum albumin (BSA) loaded nanoparticles were prepared using novel aminated (aChi) and aminated plus thiolated chitosan (atChi) polymers, to further enhance mucoadhesiveness and adjuvanticity of the vaccine system by improving electrostatic interactions of polymers with negatively charged glycoproteins. Nanocarriers with optimum size and surface charge, high encapsulation efficiency of model antigen and good stability were developed. Negligible toxicity was observed in Calu-3 and A549 cell lines. In vivo studies, revealed high levels of systemic antibodies (IgG, IgG1 and IgG2a) throughout the study and presence of sIgA in vaginal washes showed that common mucosal system was successfully stimulated. Cytokine levels indicated a mixed Th1/Th2 immune response. A shift towards cellular immune responses was observed after nasal immunisation with antigen loaded nanoparticle formulations. These nanoparticles exhibit great potential for nasal application of vaccines.

Effect of the linear aliphatic amine functionalization on in vitro transfection efficiency of chitosan nanoparticles.

The aim of this study is to prepare the long linear aliphatic amine pendant group-functionalized chitosan based nanoparticulate gene carrier system with improved properties for the efficient transfection. The amine functionalized chitosan (MChi) was synthesized by using N-(2-hydroxyethyl)ethylenediamine (HE-EDA) and characterized for the first time. The nanoparticles of MChi (nMChi) were prepared by ionic gelation method, and their particle size, polydispersity (PDI), zeta potential (mV), gene binding capacity and cytotoxicity were determined. Green Fluorescent Protein circular plasmid DNA (pEGFN1) loaded nanoparticles (gnMChi) were used in the transfection studies. The results showed that nMChi with a particle size of 102.9 nm and zeta potential of 41.9 ± 5.63 mV was non-toxic, had high transfection efficiency in Human Embryonic Kidney 293 and Primary Ovine Fibroblast cell lines and would be used as an efficient gene carrier system.

Nasal vaccination with poly(ß-amino ester)-poly(d,l-lactide-co-glycolide) hybrid nanoparticles.

Mucosal vaccination stimulates both mucosal and systemic immunity. However, mucosal applications of vaccine antigens in their free form generally result in poor systemic immune responses and need adjuvantation. In this study, bovine serum albumin loaded, new hybridised poly(ß-amino ester)-poly(d,l-lactide-co-glycolide) nanoparticles were prepared by double emulsion-solvent evaporation method, characterised and evaluated in vivo as nasal vaccine carriers. Cationic spherical particles with a mean size of 240nm, good physical stability and high encapsulation efficiency were obtained. Protein structure was not affected throughout preparation and minimal toxicity was shown in Calu-3 and A549 cells. Nasal vaccination with these nanoparticles revealed markedly higher humoral immune responses compared with free antigen following intranasal and subcutaneous immunisation. Mucosal immune response was also stimulated and cytokine titres indicated that Th1 and Th2 pathways were successfully activated. This study shows that the formulated hybrid nanoparticles can be a promising carrier for nasal immunisation of poor antigenic proteins.

The effects of the thiolation with thioglycolic acid and l-cysteine on the mucoadhesion properties of the starch-graft-poly(acrylic acid).

The aim of this study is to investigate the effects of the thiolation on the mucoadhesion characteristics of the gelatinized and crosslinked wheat starch-graft-poly(acrylic acid) [(WS-g-PAA)gc] for potential use in drug delivery via vaginal route. Thiolation of (WS-g-PAA)gc was first time realized using l-cysteine hydrochloride monohydrate (CyS) and thioglycolic acid (TGA). These conjugates [(WS-g-PAA)gcth] were characterized using FTIR. The free SH group, mucoadhesion, cytotoxicity characteristics and the mechanism of the thiolation were also evaluated. To obtain fundamental data for possible application such as drug carrier, in vitro and in vivo progesterone release profiles from the mucoadhesive tablet formulations were also determined. The results showed that, vaginal tablet containing (WS-g-PAA)gc-TGA, which has not contain free SH groups in its structure, displays higher mucoadhesion than (WS-g-PAA)gc and (WS-g-PAA)gc-CyS. This tablet formulation can also be used as a drug carrier in vaginal applications.

Development of starch based mucoadhesive vaginal drug delivery systems for application in veterinary medicine.

The aim of this study was to prepare and evaluate the mucoadhesive, biocompatible and biodegradable progesterone containing vaginal tablets based on modified starch copolymers for the estrus synchronization of ewes. Starch-graft-poly(acrylic acid) copolymers (S-g-PAA) were synthesized and characterized. The vaginal tablets were fabricated with S-g-PAA and their equilibrium swelling degree (Qe) and matrix erosion (ME%) were determined in lactate buffer solution. In vitro, mucoadhesive properties of the tablets were investigated by using ewe vaginal mucosa and in vivo residence time were also investigated. In vitro and in vivo progesterone release profiles from the tablets were compared with two commercial products. Tablet formulation containing wheat starch based grafted copolymer (WS-g-PAA)gc indicated promising results and might be convenient as an alternative product to the commercial products in veterinary medicine.