Albumin Microspheres as Vehicles for the Sustained and Controlled Release of Doxorubicin

Abstract— Biodegradable albumin microspheres have been prepared with the intention of targeting doxorubicin preferentially to tumour tissue. A high‐yielding microsphere manufacturing process has been developed that involved the denaturation of an aqueous protein emulsion by chemical and/or thermal crosslinking methods. Microspheres can be closely sized to a diameter of 25·3 ± 2·6 μm with the aid of microsieves. The in‐vitro release of doxorubicin from albumin microspheres was measured using a continuous flow system. Doxorubicin release can be sustained for up to 10 days and the rate of release could be controlled by manipulating protein denaturation conditions between the temperatures 110–135°C in the presence of 0–2% gluturaldehyde. Release of doxorubicin was significantly faster in human plasma compared with isotonic saline. 1989 Royal Pharmaceutical Society of Great Britain