Formulation Approaches and Evaluation Parameters in Microencapsulation of Diclofenac Sodium for Sustained Drug Delivery

Sustained-release microencapsules have emerged as an advanced drug delivery approach designed to enhance therapeutic efficacy and reduce the side effects associated with anti-inflammatory medications. Diclofenac sodium (DS) microcapsules were developed using ethyl cellulose as the primary polymer in different ratios (1:1, 2:3, and 2:1), along with poly(lactic-co-glycolic acid) (PLGA) and chitosan. Various formulation techniques—including emulsion solvent evaporation, microfluidics, and spray drying—were employed to encapsulate the anti-inflammatory agent. In vitro release studies confirmed that all prepared batches exhibited controlled and sustained drug release over a period of 10 to 12 hours. The novel formulation method was assessed for its efficiency in producing microcapsules with uniform particle size, good flow characteristics, consistent drug loading, high entrapment efficiency, and no observable interaction between the drug, polymers, and processing parameters. Additionally, the release profiles indicated that a higher concentration of coating material led to a slower drug release. Kinetic analysis of the drug release data showed that the release mechanism follows a first-order kinetic model.