Shuai X, Ai H, Nasongkla N, Kim S, Gao J. Micellar carriers based on block copolymers of poly(ε-caprolactone) and poly(ethylene glycol) for doxorubicin delivery.
J Control Release 2004;
98:415-26. [PMID:
15312997 DOI:
10.1016/j.jconrel.2004.06.003]
[Citation(s) in RCA: 565] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2004] [Accepted: 06/03/2004] [Indexed: 12/27/2022]
Abstract
Diblock copolymers of poly(epsilon-caprolactone) (PCL) and monomethoxy poly(ethylene glycol) (MPEG) with various compositions were synthesized. The amphiphilic block copolymers self-assembled into nanoscopic micelles and their hydrophobic cores encapsulated doxorubicin (DOX) in aqueous solutions. The micelle diameter increased from 22.9 to 104.9 nm with the increasing PCL block length (2.5-24.7 kDa) in the copolymer composition. Hemolytic studies showed that free DOX caused 11% hemolysis at 200 microg ml(-1), while no hemolysis was detected with DOX-loaded micelles at the same drug concentration. An in vitro study at 37 degrees C demonstrated that DOX-release from micelles at pH 5.0 was much faster than that at pH 7.4. Confocal laser scanning microscopy (CLSM) demonstrated that DOX-loaded micelles accumulated mostly in cytoplasm instead of cell nuclei, in contrast to free DOX. Consistent with the in vitro release and CLSM results, a cytotoxicity study demonstrated that DOX-loaded micelles exhibited time-delayed cytotoxicity in human MCF-7 breast cancer cells.
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