Preparation and evaluation of lipid vesicles of camptothecin as targeted drug delivery system

ABSTRACT

Site-specific delivery of anticancer based therapy of human cancers has led to several remarkable outcomes, particularly in the therapy of breast cancer and lymphoma. Camptothecin, a plant secondary metabolite is widely used in the treatment of metastatic breast cancer and lymphoma. However its side effect profile often results in cessation of therapy. In this study the principle of both active as well as passive targeting using camptothecin loaded stealth liposomes as per the magic gun approach was followed. Stealth liposomes of camtothecin were prepared by thin film hydration method using a PEGylated phospholipid like DSPE-MPEG 2000. Similarly conventional liposomes were prepared using phospholipids like DPPC, DSPC. Conventional liposomes were coated with a hydrophilic biocompatible polymer like chitosan. It was found that chitosan coating of the conventional liposomes increased the physical stability of the liposomal suspension. Further, chitosan coated conventional liposomes and the PEGylated liposomes released the drug for a prolonged period of time, compared to the uncoated conventional liposomes. In vivo screening of the formulations for their antitumor efficacy was carried out in rats. Breast cancer was induced in female Sprague-Dawley rats using an indirectly acting chemical carcinogen DMBA [7, 12 dimethyl benz[a]anthracene]. It was found that there was significant decrease [P<0.01] in tumor volume in the rat group treated with test 2 formulation and test 1 formulation compared to standard free CPT. However the chitosan coated liposomal formulation showed a better antitumor efficacy than that of the PEGylated liposomal formulation