[Investigations on preparation and release behavior in vitro of 9-nitro camptothecin encapsulated micelles].

9-nitro camptothecin (9-NC) loaded amphiphilic copolymer micelles were prepared with solvent evaporation method. The effects of temperature, distilled water volume, stirring rate, and drug input amount on the size and drug content of micelles were further discussed. As a result, well dispersed spherical micelles with drug content of 4.9 percent and 50 -70 nanometers in diameter were achieved with the following preparation conditions: water bath temperature 60 degrees C , distilled water amount 16 ml, stirring rate 6 500 r/min, and drug input amount 1.2 mg. 9-NC release profiles in vitro illustrated that drug release from micelles included initial burst release and following controlled release. The release rate was decreased with the increase of drug content.