Patent ID: 8067432

Claim:
A method for preparing a stable dispersion of a camptothecin or analog thereof for delivery to a patient in need thereof, comprising: preparing a solution of a camptothecin, camptothecin prodrug, or analog thereof, said solution having a pH which places substantially an entirety of that camptothecin or analog thereof in a carboxylate form; loading the solution of camptothecin, camptothecin prodrug, or analog thereof into a liposome comprised of at least one lipid, said liposome having an intraliposomal pH which preserves substantially an entirety of said camptothecin, camptothecin prodrug, or analog thereof in the carboxylate form, said at least one lipid being selected to provide to said liposome a net neutral or anionic charge; and delivering said liposome loaded with said carboxylate form camptothecin, camptothecin prodrug, or analog thereof to a patient in need thereof, whereby said liposome accumulates at a tumor site and said camptothecin, camptothecin prodrug, or analog thereof is released as an active, lactone form in situ at said tumor site.