Synthesis and characterization of ZIF-8 nanoparticles for controlled release of 6-mercaptopurine drug

Zeolitic imidazolate framework (ZIF-8) has been synthesized at room temperature in aqueous medium. Their suitability as potential drug carrier for delivery of an anti-leukemia drug, 6-mercaptopurine (6-MP) is examined. 6-MP was loaded in situ into the ZIF-8 nanoparticles during synthesis. Both ZIF-8 and 6-MP@ZIF-8 have been characterized using various characterization tools. The structural integrity and phase purity of 6-MP@ZIF-8 nanoparticles was obtained through X-ray diffraction pattern and was comparable to that of sodalite type ZIF-8. FESEM micrographs of pure ZIF-8 showed hexagonal nanocrystals with well-developed facets and uniform particle size distribution of around 80–100 nm. Encapsulation of 6-MP into ZIF-8 resulted into a nearly two fold increase of size while preserving the well-developed facets and hexagonal morphology. The encapsulation of 6-MP was confirmed by UV-Visible and FTIR spectroscopy studies. Furthermore, the release kinetics of 6-MP drug from 6-MP@ZIF-8 has been investigated in phosphate buffer saline 37 °C at two different pH values 7.4 and 5.0. The 6-MP@ZIF-8 exhibited much faster release of drug in acidic pH as compared with release in pH 7.4 owing to the decomposition of ZIF-8 structure, thus, indicating the potential of ZIF-8 to be used as a carrier for controlled delivery of 6-MP against cancerous cells