An investigation of diclofenac sodium release from cetylpyridinium chloride-modified natural zeolite as a pharmaceutical excipient

Abstract

In this paper, investigations of zeolite - cationic surfactant - drug composites as drug carriers were performed. For that purpose, after adsorption of the model drug - diclofenac sodium (DS) onto composites obtained by the modification of natural zeolite (NZ) with cetylpyridinium chloride (CPC) at the three different levels, i.e., 10, 20 and 30 mmol/100 g (ZCPC-10, ZCPC-20 and ZCPC-30, respectively), the release of the drug, at pH 6.8, was studied. The results of DS release from ZCPC-10 composite (DS/ZCPC-10) were compared with the DS release from corresponding physical mixture, as well as from physical mixture of NZ and DS. Characterization of the composites after adsorption of DS and the physical mixtures was realized by zeta potential measurements and by thermal analysis. Results showed that the prolonged release of DS from all the three composites, as well as from physical mixture containing ZCPC-10 and DS was achieved over a period of 8 h. The drug release from both DS/ZCPC-10 (max 55%) and corresponding physical mixture (max 38%) was remarkably lower than that from the physical mixture of NZ and DS (max 85%). The kinetic analysis for all the three composites, as well as for the physical mixture of ZCPC-10 and DS, showed that drug release profiles were best fitted with the Korsmeyer-Peppas and Bhaskar release models, indicating a combination of drug diffusion and ion exchange as the predominant release mechanisms in the dissolution medium.