carvedilol parenteral sustained release systems by iv infusion , injection , or subcutaneous routes are disclosed . preparation of carvedilol disperse systems such as liposomes , biodegradable microparticles or nanparticles , and polymeric microparticles or nanparticles have been presented in the present invention . compositions containing carvedilol encapsulated in liposomes showed higher bioavailability and lower clearance rate than that of the free solution after intravenous administration . in vitro release of those liposomes in buffer solutions shows drug extended release over 48 hours , and correspondingly the in vivo animal data shows that parenteral administration of carvedilol encapsulated in liposomal materials has sustained release pk profile .