两种尿激酶脂质体制备方法的比较

Comparison of two methods of preparing liposomal-encapsulated urokinase

作者采用去污剂清除技术（ＤＲＴ）和逆相蒸发法（ＲＰＥ）制备尿激酶脂质体（ＬＥＵＫ），包裹率分别为２５．６％和２７．７％．负染电镜技术观察ＤＲＴ法制备的脂质体直径６０．４±１３．６ｎｍ，属均匀大单层脂质体；ＲＰＥ法制备的４０．２±２１．０ｎｍ，以小单层为主，均一性较差．经测定尿激酶（ＵＫ）活性得知，ＬＥＵＫ在４℃和２４℃缓冲液中贮存４８ｈ，仅约１０％ＵＫ自脂质体漏出或活性丧失．在３７℃少含血小板血浆（ＰＰＰ）中孵化ＬＥＵＫ，ＵＫ后，均导致ＵＫ活性的丧失，但剩余ＵＫ活性ＬＥＵＫ组显著高于ＵＫ组．ＬＥＵＫ半衰期延长一倍多．

Liposomal-encapsulated urokinase(LEUK )was prepared through detergent removal technique (DRT)and reverse-phase evaporation(RPE).Their encapsulation rates of urokinase (UK)were 25.6%and 27.7%,respectively.Liposomes were examined by negative staining electron microscope.The results showed that the LEUK prepared by DRT was large, well-distributed,unilaminar vesicles and its mean diam-eter was 60.4±13.6 nm.The LEUK by RPE was smaller with 40.2±21.0 nm in mean size,but the unifor-mity was not very satisfying.Measurement of UK activity for LEUK indicated about 10%loss of activity or leakage in Tris-buffered saline over 48-h period at temperatures of 4℃ and 24℃.Incubation of UK and LEUK in platelet-poor plasma (PPP)at 37℃ resulted in a decrease of UK activity.The retention of activity in LEUK was considerably higher than that of UK.The half-life of LEUK was prolonged more than two times.