An efficient injectable formulation with block copolymer micelles for hydrophobic antitumor candidate-pyridazinone derivatives

Aim: To make delivery improvements via delivery systems for 6-(4-morpholino-3-(trifluoromethyl)phenyl)pyridazin-3(2H)-one (DZO) – a model compound of hydrophobic antitumor candidate pyridazinone derivatives. Materials & methods: Methoxy poly(ethylene glycol)-poly(d,l-lactide) (MPEG-PDLLA) micelle was employed as a vector, and DZO was encapsulated in. The DZO-loaded micelles were characterized in detail and its cytotoxicity, maximum tolerated dose (MTD) and pharmacokinetic experiments were done. In vivo anticancer activity was studied through a subcutaneous 4T1 tumor model. Results: Compared with free DZO, the DZO-loaded micelles possessed a sustained release property, an improved MTD, better pharmacokinetic parameters and an enhanced antitumor activity for subcutaneous 4T1 model in vivo. Conclusion: An effective injectable delivery system for DZO was developed successfully.