Sodium Diclofenac Encapsulation: Optimization of Encapsulation Efficiency and Particle Size Using Response Surface Methodology

This study was carried out to optimize conditions for diclofenac microencapsulation using response surface methodology (RSM). The paper describes preparation, characterization and the microencapsulation optimization of diclofenac-loaded pectin-gelatin beads prepared by method of complex coacervation. The obtained particles exhibit the drug encapsulation efficiency varying within 96.79 to 99.55% and the average microparticle size varying from 25.54 to 57.35 μm. The particle surface morphology was analyzed by SEM and the drug–polymer interaction in the particle matrix was studied by FTIR spectroscopy. Statistical analysis reveals that the concentration of carboxymethylcellulose (CMC) is the most important factor influencing the particle size variation while the diclofenac concentration is the most important factor determining the drug encapsulation efficiency. The RSM study gives an experimental domain that allows elaboration of the smallest particles and highest encapsulation efficiency with a desirability of 0.88.