Clinoptilolite–surfactant composites as drug support: A new potential application

Abstract A new potential application of purified natural clinoptilolite (NZ) has been explored. Three kinds of surfactants (cationic, anionic and non-ionic) have been employed for the obtainment of different surfactant/natural zeolite composites. The incorporation of two model drugs (sulfamethoxazole (S) and metronidazole (M)) as guest compound was also evaluated. It was demonstrated that the anionic and non-ionic surfactants are moderately adsorbed by the zeolite, while the cationic surfactant (benzalkonium chloride, BC) is noticeably adsorbed by NZ, which was evaluated by thermogravimetric analysis (TG). The drug adsorption assays showed that only the NZ–BC composite adsorbs a considerable amount of drug, in particular of sulfamethoxazole, which was evaluated by UV spectroscopy. It was proven by means of TG that the composites are more stable thermally when the admicelles contain sulfamethoxazole in their interior. The studies by IR spectroscopy indicated that the zeolite structure remained unchanged after the modification with the surfactant and the drug. The results of desorption of sulfamethoxazole showed that approximately 80% of the drug was released from the NZ–BC–S system in about 24 h.