[Rubomycin microincapsulation with biodegradable polymer matrix].

Abstract

A procedure for preparation of microspheres from biodegradable linear polyether of microbiological origin (polyhydroxybutirate, PHB) with using the technology of solvent evaporation was developed considering a specific example of two- and three-component emulsions. The procedure provided permanent preparation of the microspheres of high quality. The influence of the procedure (emulsion type, dispersion process and medium temperature) on the yield of the microspheres, their structure and size was shown. The temperature had a significant impact on incorporation of the antitumor anthracycline antibiotic daunorubicin (rubomycin) to the polymer matrix. The microspheres with various levels of the drug load (29 and 90% of the initial content in the emulsion) were prepared and the kinetics of the in vitro rubomycin release was studied. The dynamics of the highly toxic rubomycin release from the microspheres was on the whole even with the curve profile reaching the plateau in 20-22 hours of the observation period. The rate of the rubomycin release to the medium depended on the value of the antibiotic incorporation and was maximum within the first two hours (3.3 and 13.0 mcg/ml.h) that corresponded to the release of 0.97 and 3.89 of the incorporated antibiotic. The average rate of rubomycin release during 300 hours was 0.81 x 10(-4) and 2.3 x 10(-4) mcg/ml x h. The release constituted respectively 3.9 and 13.11% of the antibiotic incorporated to the microspheres.