a method for preparing a stable dispersion of a camptothecin , camptothecin prodrug , or analog thereof for administration to a patient in need thereof includes preparing a solution of the camptothecin , wherein the solution has a ph which places substantially an entirety of that camptothecin in a carboxylate form . the camptothecin may be a neutral camptothecin . the solution is next loaded into a liposome including at least one lipid , which may be a phospholipid . an intraliposomal ph is maintained which preserves substantially an entirety of the camptothecin in the carboxylate form . the liposomal dispersion is administered to an individual in need thereof , whereby the liposomes accumulate at and permeate into tumor tissue and an active , lactone form camptothecin is released in situ at the tumor site . compositions formulated in accordance with the described method for treatment of a cancer in an animal in need thereof are provided also .