Zeolites in drug delivery: Progress, challenges and opportunities

•Zeolites have shown tunable structures, chemical stability and biocompatibility features.•Zeolites because of various pore sizes and structures have shown a high loading efficacy.•Zeolites can carry various types of therapeutic agents such as drugs and proteins.•Zeolite structures can be adjusted on-demand, based on the type of drug and delivery route.•Zeolite modification can even results in stimuli-responsive carriers for advanced delivery. There are continuing attempts to achieve appropriate controlled-release therapeutic systems by designing innovative functional drug delivery systems (DDS). Although various types of delivery system have been developed, strategies that have successfully made it to the clinic are rare. Given their diverse structures, zeolites have attracted significant research attention for controlled and targeted drug delivery purposes. The structure of zeolites can be microporous, mesoporous or macroporous, which can be exploited to deliver a variety of therapeutic agents to the target site in a controlled manner. In this review, we introduce the different types of zeolite, and discuss the challenges and opportunities associated with their usage as drug delivery systems. Zeolites are a focus of research in drug discovery because of their adjustable pore and surface features, which could be exploited for tunable/controlled drug delivery.