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

Polymeric micro-networks architecture (PMNs) based on chitosan and its graft copolymer with acrylamidoglycolic acid (AGA) by precipitation and cross-linking methods for the controlled release of 5-fluorouracil (5-FU) is described. The chitosan and its graft copolymers are cross-linked with different ratios of urea-formaldehyde (UF) in the presence of acidic alcohol media at room temperature. The networks are characterized by Fourier transform infrared spectroscopy, particle size analysis, scanning electron microscopy, differential scanning calorimetry, and X-ray diffraction studies. The physicochemical characteristics (i.e., encapsulation efficiency, 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 release characteristics. Extent of drug loading on the encapsulation efficiency of the microparticles is investigated to prove their linear relationship. The in vitro release performed in 1.2 pH solution followed by 7.4 pH buffer media, has been analyzed with an empirical equation to understand the diffusion nature of drug solution through the PMNs. The study of 5-FU loaded PMNs shows that the extended release rates are noticed from the conventional dosage release duration beyond 18 h.