Encapsulation of natural drug gentiopicroside into zinc based Zeolitic Imidazolate Frameworks (ZIF-8): In-vitro drug release and improved antibacterial activity

In the present study, multifunctional natural drug gentiopicroside (GPS) has been encapsulated into zeolitic imidazolate frameworks (ZIF-8) in aqueous solution at room temperature. ZIF-8 MOFs were observed to be suitable and favorable carrier for delivery of GPS. The single step synthesis of GPS@ZIF-8 reflected high loading efficacy of GPS into ZIF-8 of about 84%, while, its loading capacity was revealed to be 10.77%. GPS@ZIF-8 and ZIF-8 were characterized through different techniques. Morphology of GPS@ZIF-8, assessed through SEM and TEM, revealed to be uniform and hexagonal shape which is much alike to pure ZIF-8. Moreover, average particle size of ZIF-8 and GPS loaded into ZIF-8, as observed through DLS, was 125 nm and 149 nm, respectively; increased size of GPS@ZIF-8 depicted a well efficient encapsulation of GPS. The thermal stability showed that the GPS when loaded into ZIF-8 remained thermally constant up to 298 °C. The free drug GPS release profile from GPS@ZIF-8 was studied at 37 °C in PBS solution with two pH i.e. 5.0 and 7.4. The GPS@ZIF-8 reflected significant faster release of GPS in acidic medium i.e. 81.31% which was higher than the release of GPS in physiological medium i.e. 20.03%. Thus, results of the present study revealed that the ZIF-8 can be used as a potential carrier for controlled delivery of GPS against diseased cells in future. GPS@ZIF-8 in contrast to free GPS showed highest inhibition zone against gram-negative and gram-positive bacteria. Therefore, the composite material can be potentially considered for the therapeutic applications.