Our research focused on the preparation of vesicular drug delivery systems, such as liposomes, noisomes, and sphingosomes, for achieving slow release of entrapped proteins in the circulation to increase half-life, to mask immunogenic properties, and to protect against loss of enzymatic activity. We prepared, characterized, and monitored the biodistribution of three types of vesicular systems ( liposomes, niosomes, and sphingosomes) containing streptokinase. For biodistribution stuides, radiolabelled streptokinase dispersions were injected into the ear vein of female rabbits in the weight of 2.5 - 3 kg weight. Following the application, rabbits were sacrificed, then organs of these animals were removed and radioactivity of organs was measured by well-type gamma counter. The comparison of the biodistribution results of the free streptokinase with the streptokinase vesicles showed that incorporation of the enzyme into the vesicles changed the biodistribution of the drug and by the entrapment of the streptokinase in the vesicles, thrombus uptake and imaging quality were improved.