The present invention is directed to a method for treating cancer intraperitoneally in a subject. The method comprises administering to said subject in need thereof an anti-cancer agent encapsulated in nanoparticles wherein nanoparticles are characterized to slowly release anticancer agent in a timely fashion that allows efficient killing of tumor cells. The nanoparticles described herein are characterized to slowly release anti-cancer agent at a rate of 30 pcnt or less per 8 hours based on dialysis.
