Synthesis and release study of tissue plasminogen activators (tPA) loaded chitosan coated poly (lactide-co-glycolide acid) nanoparticles

Polyelectrolyte coated nanopatrticles (NPs) interact with bioactive molecules such as, peptides, proteins or nucleic acids and have been proposed as delivery systems for these molecules. In this study, cationic NPs were prepared by coating chitosan (CS) on the surface of PLGA NPs. The tPA encapsulated PLGA and PLGA/ CS NPs were fabricated via the W/O/W double emulsion solvent evaporation surface coating method. The CS coating was confirmed by zeta potential and FTIR. The surface morphology of NPs was also studied by TEM. In vitro drug release experiments of tPA encapsulated PLGA and PLGA/CS are determined by HPLC and showed a sustained release profile for three days with little initial burst release for PLGA/CS NPs. The mean particle size and encapsulation efficiency of tPA NPs were in the range of 280-360 nm and 46.7%±1.56, 50.8%±1.09, respectively. The encapsulation efficiency and the particles size were increased as a result of coating with CS. The release kinetics was evaluated by fitting the experimental data to standard release equation (Higuchie equation). This model was used to find the best fit for NPs. These results suggest that PLGA/CS NPs could serve as an effective vehicle for local delivery of tPA.