Novel Chitosan-based pH Sensitive Micro-networksfor the Controlled Release of 5-Fluorouracil

Polymeric micro-networks architecture (PMNs) based on chitosan and its graftcopolymer with acrylamidoglycolic acid (AGA) by precipitation and cross-linkingmethods for the controlled release of 5-fluorouracil (5-FU) is described. Thechitosan and its graft copolymers are cross-linked with different ratios of ureaformaldehyde(UF) in the presence of acidic alcohol media at room temperature. Thenetworks are characterized by Fourier transform infrared spectroscopy, particle sizeanalysis, scanning electron microscopy, differential scanning calorimetry, andX-ray diffraction studies. The physicochemical characteristics (i.e., encapsulationefficiency, density, particle size distribution, in vitro release) of the PMNs are reported.The extent of cross-linking is studied in terms of size of PMNs as well as their releasecharacteristics. Extent of drug loading on the encapsulation efficiency of themicroparticles is investigated to prove their linear relationship. The in vitro releaseperformed in 1.2 pH solution followed by 7.4 pH buffer media, has been analyzed withan empirical equation to understand the diffusion nature of drug solution through thePMNs. The study of 5-FU loaded PMNs shows that the extended release rates arenoticed from the conventional dosage release duration beyond 18 h.