A novel star-shaped copolymer was prepared by tolulene diisocyanate (TDI) trimer, poly(ethylene oxide) (PEO), P(2-(dimethylamino)ethyl methacrylate) (PDMAEMA), and 2-hydroxyethylacrylate (EEA) with TDI trimer as core and PEO, PDMAEMA as arm chains by addition of functional groups and copolymerization. The structure of the star-shaped copolymer was characterized by FTIR, H-1 NMR, and UV, and the molecular weight and polydispersity were determined by gel permeation chromatography (GPC). Their aqueous solution properties and controlled coenzyme A (Co A) delivery were also studied. The results showed that the copolymer had better temperature sensitivity and pH sensitivity. The release of Co A from the copolymer was dependent on the release medium such as concentration of the polymer, pH, and temperature in the aqueous solution. The higher concentration of the copolymer absorbed more Co A than the lower one. The increasing temperature accelerated Co A release from the copolymer. The pH of the solution had significant impact on the release of Co A from the copolymer. The results suggested that the novel copolymer could be used as a drug delivery carrier. (c) 2007 Wiley Periodicals, Inc. J Appl Polyrn Sci 104: 1279-1284, 2007.