Surfactant-modified natural zeolites as carriers for diclofenac sodium release: A preliminary feasibility study for pharmaceutical applications

This research aimed to investigate the feasibility of using cetyltrimethylammonium bromide-modified natural zeolites (clinoptilolite and chabazite) as carriers for diclofenac sodium release. The surfactant-modified natural zeolites were characterized by X-ray fluorescence, X-ray powder diffraction, scanning electron microscopy, thermogravimetric analysis, differential thermogravimetric analysis, and Brunauer-Emmett-Teller surface area analysis. On the other hand, drug adsorption and in vitro release kinetics in simulated intestinal fluid were also investigated to assess the potential pharmaceutical applications of clinoptilolite and chabazite. Results showed that the higher the surfactant concentration, the greater the adsorption capacity of the surface-modified natural zeolites due to the formation of bilayers on their surface. Diclofenac sodium adsorption tests on natural zeolites showed that the adsorption capacity was lower in the natural zeolites than in the surfactant-modified natural zeolites, which indicates that the modification with the surfactant enhanced diclofenac sodium release. The surfactant-modified chabazite showed a very rapid 100% release of diclofenac sodium after 3 h, so it is not suitable for prolonged release, whereas the surfactant-modified clinoptilolite showed a rapid initial release, but maintained a gradual release, being suitable for prolonged release since after 6 h a 100% released of diclofenac sodium was not achieved. The surfactant-modified clinoptilolite is more efficient than the surfactant-modified chabazite as a carrier for diclofenac sodium. •Natural zeolite-rich rocks were superficially modified with CTAB surfactant and loaded with diclofenac sodium (DS).•Surface modified natural zeolites are interesting as carrier-liberator systems of DS.•DS adsorption on natural zeolites show lower adsorption capacity than the surface modified natural zeolites.•Surfactant-modified natural zeolites can be used as pharmaceutical excipients.