Abstract
In this work, the feasibility to develop micelle carriers of griseofulvin based on PLA‐PEG copolymers was investigated. With the use of the dialysis method of micelle formation, the micellization behavior of a range of PLA(X)‐PEG(5) copolymers was investigated. At copolymer concentrations in the organic solvent 10–20 mg/mL, stable micelles with 100% yield could only be prepared from PLA(X)‐PEG(5) copolymers with molar composition in the range 50–70% PEG. The copolymers exhibited sufficiently low CMC to provide stable micelles in vivo. The loading capacity of PLA(4)‐PEG(5) micelles with griseofulvin was 6.5 mg of drug/1 g of copolymer. The release of griseofulvin from the PLA‐PEG micelles in vitro in phosphate‐buffered saline (PBS) was sustained over 30 days. No burst effect was observed. Analysis of the release kinetics suggested that the release was erosion‐controlled. The release profile was biphasic. Micelle degradation data in PBS indicated that the second phase of release was induced by copolymer degradation. The PLA‐PEG micelles of griseofulvin were stable in simulated gastric and intestinal fluids for a long‐enough time for oral application. Overall, the PLA‐PEG micelles have suitable properties to be considered as potential oral or topical formulations of griseofulvin, provided that the drug‐loading capacity of the micelles is sufficiently improved. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005