Formulation study for the antitumor drug camptothecin: liposomes, micellar solutions and a microemulsion

In the present paper we describe the production and characterization of specialized delivery systems for camptothecin, namely liposomes, micellar solutions and microemulsion. For instance, liposomes were prepared by reverse phase evaporation technique followed by extrusion through polycarbonate filters. Liposomes were characterized in term of dimensions, morphology and encapsulation efficacy. All the formulations were designed firstly to increase the solubility of camptothecin in aqueous environment and secondly to reduce the toxicity problems related to the administration of this drug. The analysis of their in vitro antiproliferative activity on cultured human leukemic K562 cells demonstrated that liposomes, micellar solutions and microemulsion containing camptothecin exert similar or slightly enhanced effect as compared to that shown by the free drug. Based on these results, the specialized delivery systems here proposed typify an interesting starting point for a future use in experimental therapy. (C) 1997 Elsevier Science B.V.