Preparation, characterization and in vitro thrombolytic activity of a novel streptokinase foam

Vascular thrombosis is a potentially fatal disease. Thrombolysis represents an efficient therapeutic option, although it still presents intrinsic bleeding risks. In order to minimize this problem, intra-thrombus injections, alone or associated with some kind of mechanical thrombectomy, have been used. In this work, a new approach to thrombolysis is presented, where the preparation, characterization and in vitro thrombolytic activity of a novel streptokinase foam are reported. Foams were prepared by mixing albumin solution with CO₂ at different volume ratios. Foam stability and apparent viscosity were the parameters used to characterize the foams. The volume ratio between CO₂ and albumin solution that yielded the samples with the best properties was used to prepare the thrombolytic foams, where streptokinase was used as the thrombolytic agent. The thrombolytic effect of this foam was assessed in vitro by delivering it intra-thrombus and the results were compared with those of the foam without streptokinase as well as those of a regular streptokinase solution. Both foam stability and viscosity increased as the ratio of CO₂:albumin solution increased and the 3:1 ratio was used to incorporate streptokinase. The in vitro thrombolytic activity study revealed that the streptokinase foam caused a 46.6 % of thrombus lysis after 30 min of experiment against 21 and 31 % of those of the foam without streptokinase and the regular streptokinase liquid solution, respectively. Thus, the use of CO₂:albumin foam enhanced the in vitro thrombolytic effect of streptokinase, which indicates its potential as a novel vehicle for carrying and delivering streptokinase to targeted thrombi.