Long-term preservation of human platelets will greatly reduce the risk of their shortage. Lyophilization has been proved feasible for this purpose. For the recovery of lyophilized platelets,rehydration is an important process. In this paper,the rehydration proc-esses for 1 mL and 2 mL samples were studied. The effects of prehydration duration(15,30,60,90,120 and 150 min) in 37°C water vapor and the concentration of rehydration solution(25%,50%,75%,100% platelet-poor plasma) on the recovery rate,MPV(mean platelet volume) and PDW(platelet distribution width) were investigated. The mass changes during the prehydration process were weighed. The optimized rehydration conditions are as follows:(1) for 1 mL sample,the prehydration duration was 15 min and for 2 mL sample the prehydration duration was 90 min;(2) the rehydration solution was 75% platelet-poor plasma. Under optimized conditions,the morphology of the rehydrated platelets kept normal and their ultrastructures kept intact,their aggregation capacity to thrombin(1 U/mL) was 82.8% of the fresh ones. These results will be helpful for designing the freeze-drying protocols for human platelets.
FAN JuLiXU XianGuoZHANG ShaoZhiXU MengJieZHU FaMingCHEN GuangMing
Freeze-drying is a promising method for a long-term storage of human platelets.The moisture sorption characteristics of freeze-dried human platelets(FDHPs) were studied in this paper.The moisture sorption isotherms of FDHPs and freeze-dried lyophilization buffer(FDLB) were measured at 4,25,and 37°C.The experimental data were fitted to Brunauer-Emmett-Teller(BET) and Guggenheim-Anderson-de Boer(GAB) equations.There were no sig-nificant statistical differences(P>0.05) between the sorption characteristics of FDHPs and FDLB at 4 and 25°C,while FDHPs absorbed more water at 37°C.The net isosteric heat of sorption was derived.The heat for FDHPs showed an abnormal negative value at low moisture contents when 25 and 37°C data were used.Dynamic sorption experiments were carried out at 25°C with environmental water activity controlled at 0.75,0.85,and 0.90.The moisture diffusion coefficient was fitted to be 8.24×10 -12 m 2 /s when experimental data at initial time were used.These results would be helpful in choosing prehydration and storage condition for FDHPs.
