Preparation and In Vitro Evaluation of Chitosan Nanoparticles Containing Diclofenac Using the Ion-Gelation Method

Abstract

Background: Chitosan-based nanoparticle systems have gained wide interest, mainly for their biocompatibility, biodegradability and mucoadhesive properties. Objectives: The aim of this study was to prepare and evaluate diclofenac-loaded chitosan nanoparticles based on the ionotropic gelation method. Materials and Methods: Chitosan (CS) nanoparticles containing diclofenac was prepared using the ionotropic gelation method. Sodium tripolyphosphate (TPP) was used as a polyanion in this process. The effect of some parameters on particle size and drug loading efficiency was evaluated. Results: Transmission electron microscopy (TEM) photographs exhibited typical spherical shape of particles. The mean particle size was within 129 - 166 nm and was affected by homogenization, CS/TPP ratio, CS/drug ratio and pH of medium. The maximum drug loading efficiency was estimated as 65.43 ± 7.03% with CS/drug ratio of 10:1. This value tended to decrease by enhancement of drug proportion in the formulations. Differential scanning calorimetry data confirmed the formation of polyelectrolyte complex of TPP and chitosan. Drug release profile in phosphate buffer solutions (pH 6.8, 7.4) showed initial burst effect followed by a slower release pattern. However, release of diclofenac in the acidic medium was negligible. Conclusions: Diclofenac-loaded nanoparticles based on properties of chitosan gelation could delay the release of drugs in the stomach and be further evaluated for the enteric delivery of diclofenac.