Abstract: Objective To investigate the effect of varied freezing temperature and time on the recovery and residual water in the freeze-dried platelets. Method The freeze-drying processes of temperature and time were divided into three types (A, B and C). The platelets were freeze-dried and rehydrated using the three types of freeze-drying processes,respectively. The residual water content of the lyophilized platelets was detected with dry-weighing method.The differences of the recovery rate and residual water,and the MPV and PDW values in the freeze-dried platelets were compared. Result

The difference between freezing temperature/time for the freeze-drying platelets，the difference of the MPV values after the rehydration of freeze-dried platelets were not statistically significant （P>0.05）. The PDW value of freeze-dried platelets after rehydration between type A and type C showed no significant difference （P>0.05）, while that of type B was high （P<0.05）. The recovery rate of types A, B and C rehydration platelets was （81.72±12.43）%，（81.40±8.79）% and （94.37±7.02）%, respectively, with no significant difference among the three types （P>0.05）. The lyophilized platelets residual water contents in types A, B and C were （6.55±0.96）%，（7.10±1.20）%，and （5.18±0.89）%， respectively，with no significant difference among the three types （P>0.05）. Conclusion Based on the residual water and recovery of the freeze-dried platelets by using various processes，freeze-drying temperature and time should be optimized.