Thiabendazole/bentonites hybrids as controlled release systems.

Clay minerals are commonly used in pharmaceutical products as excipients and active agents. New drug vehicles based on clay minerals have been developed. In this work, sodium (BentNa), calcium (BentCa) and magnesium (BentMg) exchanged bentonites were used for the sorption of thiabendazole (TBZ), and their potential use as controlled release systems was evaluated. Pristine bentonite and exchanged bentonites were characterized by X-ray diffraction, infrared spectroscopy, thermogravimetry and transmission electron microscopy (TEM), and the influence of the different parameters such as pH, contact time and initial concentration of the drug was investigated. The maximum adsorption reached after 45 min period with 2000 mg L-1 of thiabendazole to BentNa and after 105 min with 1300 mg L-1 to BentCa and BentMg, respectively. The maximum adsorbed quantities of thiabendazole were 164.4; 152.3 and 133.3 mg g-1 for BentNa, BentCa and BentMg, respectively. The emission profiles obtained for the bentonite/drug hybrids were similar when simulated body fluids were used and these emission profiles were fitted according to the Korsmeyer-Peppas kinetic model.