Organotin(IV) compounds loaded in thermo- and pH-responsive smart polymeric nanocarriers based on poly(DEGMA-co-OEGMA)-b-poly(DEAEM) a drug releasing system and in vitro anticancer activity

Abstract

Nanocarriers in cancer treatment are important for transport and release of insoluble drugs. In this work, block thermo- and pH-responsive copolymers based on poly(di(ethylene glycol) methyl ether methacrylate-co-oligo(ethylene glycol) methyl ether methacrylate) (PDO) and poly(2-(N,N-diethylamino)ethyl methacrylate) (PDEA) were tested. At pH 7.4 and 37 °C, the title polymers formed micelles which were used for the loading and release of diorganotin(IV) complexes (LSnR2), where L is a Schiff base ligand and R = n-butyl (LSnBu2) or cyclohexyl (LSnCy2). Results revealed that the PDO-b-PDE block copolymers could enhance the solubility of LSnR2(IV) compounds in PBS at pH = 7.4, resulting in good loading capacity (%DLC) and loading efficiency (%DLE), and better release performance (pH-dependent and T-dependent) than the free compound. In vitro cytotoxic activity was evaluated by the sulforhodamine B (SRB) assay against a normal cell line, African green monkey kidney fibroblast (COS-7) and seven human cancer cell lines prostate (PC-3), leukemia (K-562), colon (HCT-15), lung (SKLU-1), central nervous system glia (U-251), breast Strogen receptor-positive (MCF-7) and breast hormone-independent (MDA-MB-231). The non-loaded block copolymers were non-cytotoxic, but the loaded ones showed high cell growth inhibition against human cancer cell lines. Results confirmed that these temperature and pH-sensitive polymeric systems are excellent candidates for the loading and release of potential metallodrugs, such as LSnR2, against diverse types of cancers.