Design and Optimization of Chitosan-Based Microspheres for Sustained Delivery of Anastrozole

Abstract

The present study aimed to develop and evaluate Anastrozole-loaded mucoadhesive microspheres for sustained oral drug delivery using Sodium CMC, Chitosan, and HPMC K4M polymers. Microspheres were prepared by the solvent evaporation method and characterized for their micromeritic properties, percentage yield, drug entrapment efficiency, swelling behavior, mucoadhesion, surface morphology, and in vitro drug release. The prepared formulations exhibited satisfactory flow properties with particle sizes ranging from 420.15 to 468.41 µm. Percentage yield and drug entrapment efficiency were found to be in the ranges of 88.31–99.52% and 87.14–99.82%, respectively. The microspheres demonstrated excellent swelling and mucoadhesive characteristics, indicating their suitability for prolonged gastrointestinal residence. In vitro dissolution studies revealed sustained drug release for up to 12 h, with cumulative drug release ranging from 85.87% to 99.92%. Among all formulations, A6 containing Chitosan at a drug-to-polymer ratio of 1:2 showed the most desirable performance, achieving 99.92% drug release with superior mucoadhesion and controlled-release characteristics. FTIR studies confirmed the absence of significant drug–polymer interactions, while SEM analysis revealed discrete and spherical microspheres with smooth surface morphology. Drug release kinetic analysis demonstrated that the optimized formulation followed Zero-order kinetics with a non-Fickian diffusion mechanism. The findings suggest that Chitosan-based Anastrozole microspheres are a promising sustained-release oral delivery system capable of improving therapeutic efficacy and patient compliance in breast cancer management.