Effect of carboxymethyl chitosan on poly(lactic-co-glycolic acid) nanoparticles encapsulating diclofenac sodium: Characterization and in vitro release study.

Poly(lactic-co-glycolic acid) is a biocompatible, biodegradable synthetic polymer, has tunable mechanical and degradation rate properties and the capability for controlled drug release. Encapsulation diclofenac sodium using carboxymethyl chitosan-modified poly(lactic-co-glycolic acid) nanoparticles (CMCh/PLGA/DS) were synthesized to enhance gastric retention followed by a controlled release in the small intestine to reduce the side effects due to frequent administration, such as gastric irritation and renal damage. Synthesis of nanoparticles was carried out using a double emulsion (water/oil/water) solvent evaporation method with poly(vinyl alcohol) as the emulsifier. Studies using infrared spectrophotometer show that the interaction between diclofenac sodium and polymer on nanoparticles is non-covalent with a spherical shape based on scanning electron microscope characterization. When compared to unmodified PLGA nanoparticles (PLGA/DS), encapsulation efficiency of CMCh/PLGA/DS nanoparticles was increased with a minimum release at pH 1.2 of 0.2% and controlled release at pH 6.8 of 90.9% up to 24 hours. [ABSTRACT FROM AUTHOR]