pH responsive metformin loaded zeolitic imidazolate framework (ZIF-8) for the treatment of lung cancer

A simple and cost-effective synthesis method for zeolitic imidazolate framework-8 (ZIF-8) was developed and loaded with metformin (MET@ZIF-8) for pH sensitive-release behaviour for the treatment of lung cancer. ZIF-8 and MET@ZIF-8 were subjected to particle size, zeta potential analysis and HR-TEM through which it shows evidence that the particles had spherical morphology and nanosize. Percentage of metformin (MET) loading in the ZIF-8 was found to be 63.39 ± 1.32%. Dissociation of ZIF-8 into its coordination ions at acidic conditions (pH 5–6) thereby leads to the release of MET at a higher drug release rate (98%) compared to physiological conditions (pH 7.4) the drug release rate at 35%. Pore volume and pore size of ZIF-8 (1242 m2/g) gets reduced to 1042.00 m2/g after incorporation of MET in ZIF-8. In-vitro cytotoxicity assay results showed the enhanced cytotoxicity for MET @ZIF-8 compared to free MET in a dose dependent manner in human lung adenocarcinoma cells A549.