Objective: To investigate freeze-drying technology of hydrocamptothecin-loaded liposomes (HCPT-lipo). Method: Effect of various types and concentrations of cryoprotectives on HCPT-lipo were investigated with appearance

particle size

disparity and encapsulation efficiency as indexes

and to optimize freeze-drying technology parameters. Result: 1.5% mannitol could prevent liposomes from aggregating better as cryoprotective

optimized process was as follows:precooled at -45 ℃ for 10 h

maintained at -30 ℃ for 8 h

maintained at -10 ℃ for 6 h

maintained at 25 ℃ for 2 h. Conclusion: Stable HCPT-lipo could be obtained by screening cryoprotectives and optimizing freeze-drying process parameters.