PROLONGED SYSTEMIC DELIVERY OF STREPTOKINASE USING LIPOSOME

To prolong the biological half-life of streptokinase, a thrombolytic a gent, streptokinase bearing liposome with and distearolyphosphatidyl e thanolamine-N-poly (ethylene glycol) 2000 (DSPE-PEG 2000) was prepared and evaluated. Streptokinase-bearing liposomes composed of distearoly phosphatidylcholine (DSPC), cholesterol and cholesterol-3-sulfate with DSPE-PEG 2000 was prepared by the freeze-thawing method and administe red via femoral vein to rats (15000 IU/kg). The activity of streptokin ase in plasma was determined by the method based an the amidolytic act ivity of streptokinase-plasminogen complex. Pharmacokinetic parameters of streptokinase incorporated in liposomes were compared with those o f streptokinase alone. The T-1/2 and AUC(infinity) of streptokinase in corporated in DSPC-PEG liposome increased 16.3- and 6.1-fold, respecti vely, compared with those of streptokinase alone. Streptokinase-bearin g long-circulating liposome could increase the circulation time of str eptokinase in blood and expect longer thrombolytic activity compared w ith streptokinase alone.