Preparation and in vitro characterization of paclitaxel-loaded mPEG-PLA polymer micelles

GAO Min-qi; REN Heng-lei; XIE Cao; XIE Ming

Abstract：Objective:To establish a novel colloidal system composed of mPEG-PLA loaded with paclitaxel (PM-PTX) and investigate the in vitro properties.Methods:PM-PTX were prepared by thin-film dispersion method.The micelle properties and in vitro drug release were investigated.The in vitro cytotoxicity of PM-PTX against Hep-2 cancer cells was evaluated by MTT assay.Results:The micelles were spherical in shape and had smooth surface as examined by TEM.The encapsulation efficiency and drug loading were (83.04 ± 1.96)％ and (15.01 ±0.28)％,respectively.The average size of the micelles was (87.74 ± 2.3) nm,with a polydispersity index (PDI) of (0.259 ± 0.014),a zeta potential of (-1.22 t 0.133) mV.The CMC value for micelles was 0.158 mg· L-1.After 96 h,the cumulative amount of released PTX was (92.19 ± 3.17) ％,(88.37 ± 5.62) ％ and (86.04 ± 2.16) ％ under pH 5.8,7.2 and 7.4,respectively.The pH values of the release media did not notably affect the drug release patterns (P ＞ 0.05).The PTX injection showed an overall higher cytotoxicity against Hep-2 cells in comparison to PM-PTX.The time-and concentration-dependency of the cytotoxicity of PM-PTX was more obvious compared with PTX injection.Conclusion:The presently developed micelles meet the requirements on particle size for lymphatic uptake.Encapsulation of paclitaxel into sustain-released carriers seems to improve the antitumor efficiency of the drug.PM-PTX might serve as a potential antitumor drug delivery system for the treatment of lymphatic metastases of malignant tumors.