γ-Irradiated chitosan based injectable hydrogels for controlled release of drug (Montelukast sodium).

Novel pH-sensitive γ-irradiated low molecular weight (MW) chitosan (CS) (pre-irradiated) and poly (vinyl alcohol) (PVA) blended injectable hydrogels, crosslinked with varying concentrations of glycerol, were fabricated for drug delivery application. The effect of low MW irradiated CS on controlled drug release was evaluated to address the problem of higher viscosity and lower solubility of high MW CS. The FTIR spectra of hydrogels depicted the presence of all the incorporated functional groups and the developed interactions (physical and chemical). The surface morphology of hydrogels assessed by scanning electron microscope exhibited porous microstructure. All hydrogels were subjected to the swelling analysis in different media (water, buffer and electrolytes). The pH sensitive hydrogel samples exhibited less swelling at acidic and neutral pH while higher swelling at basic pH. CPG-0.5 showed the highest swelling at all pH media as compared to other hydrogel samples. CPG-1.0 was selected for the release analysis of drug because of its highest swelling (114.47%) in distilled water having neutral pH. It was loaded with model drug (Montelukast Sodium) during the preparation phase and studied for drug release capability. The in-vitro controlled release evaluation of hydrogel (CPG-1.0) was performed in SGF and SIF using UV-visible spectroscopy. The results confirmed their applications in injectable drug release systems as all the loaded drug was released in 30 min in SGF (pH -1.2) while the release of drug in SIF (pH -6.8) was in controlled manner (99.62% in 3 h). The improved antibacterial activity of these hydrogel films was owing to the fact that the γ-irradiated low MW CS has ruptured the bacterial cell and its metabolism more efficiently by inflowing in the cell.

Co-concentration effect of silane with natural extract on biodegradable polymeric films for food packaging.

Novel biodegradable films were prepared by blending guar gum, chitosan and poly (vinyl alcohol) having mint (ME) and grapefruit peel (GE) extracts and crosslinked with nontoxic tetraethoxysilane (TEOS). The co-concentration effect of TEOS with natural extracts on the films was studied. FTIR analysis confirmed the presence of incorporated components and the developed interactions among the polymer chains. The surface morphology of the films by SEM showed the hydrophilic character due to porous network structure. The films having both ME and GE with maximum amount of crosslinker (100µL), showed maximum swelling (58g/g) and stability while the optical properties showed increased protection against UV light. This film sample showed compact network structure which enhanced the ultimate tensile strength (40.03MPa) and elongation at break (104.8%). ME/GE conferred the antioxidant properties determined by radical scavenging activity and total phenolic contents (TPC) as ME films have greater TPC compared to GE films. The soil burial test exhibited the degradation of films rapidly (6days) confirming their strong microbial activity in soil. The lower water vapour transmission rate and water vapour permeability showed better shelf life; hence, these biodegradable films are environmental friendly and have potential for food and other packaging.