Optimization of Self-Assembled Chitosan/Streptokinase Nanoparticles and Evaluation of Their Cytotoxicity and...

In this study, the enzyme streptokinase (thrombolysis agent) and chitosan (Cs) nanoparticles were prepared by self-assembly. Using experimental design, chitosan concentration, solution pH and stirring time were studied as independent variables to identify their effects on size, polydispersity index (PDI) and loading efficiency of nanoparticles. Results showed that pH and concentration have a direct effect on size. Additionally, minimum PDI was observed at lowest values of concentration and highest values of stirring time. pH-5.6 was also necessary to obtain the smallest PDI and highest loading efficiency values. The model predicted that to obtain maximum loading efficiency and minimum size along with low PDI, optimum values are 0.5 mg/mL, 5.18 and 30 min for the Cs concentration, solution pH and stirring time, respectively. The corresponding mean ± SD values for experimentally prepared nanoparticles were 43 ± 10%, 526 ± 121 nm, 0.3 ± 0.2, respectively. MTT and euglobulin clot lysis assays on the optimized nanoparticles showed that chitosan/streptokinase nanoparticles have slightly toxic effect on human fetal lung fibroblast cells (Mrc-5), compared with chitosan and streptokinase alone as a control. Also, thrombolytic activity of encapsulated streptokinase in nanoparticles is decreased slightly in comparison with free streptokinase. However, the preparation keeps a good potency for use as a thrombolytic agent in vivo.