This invention provides an aqueous / t-
butanol solvent-
system, facile reconstitute, submicron-reconsitiute preliposome-lyophilaye and method of its preparation and use.In one embodiment this entails a
modified method for the preparation of a submicron and stable
liposome formulation of the non-cross-resistant
anthracycline Annamycin is described. The optimal
lipid composition was DMPC:DMPG at a 7:3
molar ratio and the optimal lipid:
drug weight ratio 50:1. The selected formulation is a preliposome lyophilized
powder that contains the phospholipids, Annamycin, and 1.7 mg Tween 20 per mg of Annamycin. The
liposome suspension is obtained on the day of use by adding normal
saline at 37° C. (1 ml per mg Annamycin) and hand-shaking for one minute. The presence of Tween 20 is essential in shortening the reconstitution step (from >2 hours to 1 minute), avoiding the early formation of
free drug crystals, and reducing the median particle size (from 1.5 μm to 0.15-0.20 μm) without destruction of the
liposome vesicles. The
chemical stability of the preliposome
powder at
room temperature was >3 months and the chemical and
physical stability of the
liposome suspension at
room temperature >24 hours. The
in vitro cytotoxicity of the formulation was equivalent to that prepared by the standard
evaporation method. The results of the study indicate that small amounts of surfactant may be used to enhance the reconstitution step and reduce the liposome size of lyophilized liposome formulations of lipophilic drugs.