Zero-order and prolonged release of atenolol from microporous FAU and BEA zeolites, and mesoporous MCM-41: experimental and theoretical investigations

The potential of microporous zeolites FAU and BEA, and mesoporous MCM-41, for prolonged release of atenolol in drug delivery systems was investigated both experimentally, using drug release studies, and theoretically using classical molecular dynamics simulations. Remarkably, zero-order release of atenolol was achieved from FAU (SiO₂:Al₂O₃ = 80:1) into phosphate buffer for 24 h followed by prolonged release for at least another 48 h. Experimental data also demonstrate the ability for all of the drug-zeolite combinations investigated to achieve prolonged release of atenolol, with the release rates determined by the combination of framework topology, aluminium content and drug release study media. Molecular dynamics simulations give an insight into the reasons for the different release rates observed for FAU and BEA. The results of this work emphasise the need for sophisticated models in order to explain subtle differences in release, such as those observed at different SiO₂:Al₂O₃ ratios.