tailieunhanh - D,L serine based Ph sensitive oligoester

In recent years, pH/temperature-sensitive polymers have attracted increasing attention as drug/protein delivery systems. In this study, the main objective was to synthesize a pH-sensitive oligoester. The oligoester was synthesized by condensation reaction from carboxylic and hydroxyl groups of D,L-Serine, which had been previously modified with benezenesulfonyl chloride in order to create sulfonamides as pH sensitive groups. | Journal of Science and Technology 54 (5A) (2016) 45-55 D,L-SERINE BASED pH-SENSITIVE OLIGOESTER Dang Nguyen Tri1, Dai Phu Huynh1, 2, * 1 Faculty of Material Technology, Ho Chi Minh University of Technology, HCMUT–VNUHCM, 268 Ly Thuong Kiet Street, Ward 14, District 10, Ho Chi Minh City 2 National Key Laboratory of Polymer and Composite Materials, HCMUT–VNUHCM, 268 Ly Thuong Kiet Street, Ward 14, District 10, Ho Chi Minh City * Email: hdphu@ Received: 15 July 2016; Accepted for publication: 3 December 2016 ABSTRACT In recent years, pH/temperature-sensitive polymers have attracted increasing attention as drug/protein delivery systems. In this study, the main objective was to synthesize a pH-sensitive oligoester. The oligoester was synthesized by condensation reaction from carboxylic and hydroxyl groups of D,L-Serine, which had been previously modified with benezenesulfonyl chloride in order to create sulfonamides as pH sensitive groups. Various molecular weights of the oligoesters were obtained by means of manipulating the mole ratio of N,N'Dicyclohexylcarbodiimide (DCC)/Serine (DCC acts as a coupling agent) and the Dimethylformamide (DMF)/Serine (v/w) ratio (DMF acts as solvent). The synthesized oligoesters were characterized by 1H-NMR and their molecular weights were measured by gel permeation chromatography (GPC). Also, the pKa values of pH-sensitive oligoesters were obtained by the titration method. This pH dependent property of the polymers could be very useful for preparing drug carriers that are sensitive to pH environment. Keywords. pH sensitive, D,L-Serine, benezenesulfonylchloride. 1. INTRODUCTION In recent years, stimuli sensitive polymers have attracted the interest of researchers for their applications in drug delivery systems and protein [1, 2]. There are many sensitive factors of environmental stimuli such as temperature, pH, light, electric field, and other stimuli [2, 3 - 7]. In particular, in the biomedicine field, throughout years,