Shim, Woo Sun Kim, Jong-Ho Park, Hungkyu Kim, Kwangmeyung Kwon, Ick Chan Lee, Doo Sung 2024-01-21T02:06:42Z 2024-01-21T02:06:42Z 2021-09-01 2006-10 0142-9612 https://pubs.kist.re.kr/handle/201004/135087 A pH- and thermo-sensitive block copolymer was synthesized by adding pH-sensitive sulfamethazine oligomers (SMOs) to either end of a thermo-sensitive poly(epsilon-caprolactone-co-lactide)-poly(ethylene glycol)-poly(epsilon-caprolactone-co-lactide) (PCLA-PEG-PCLA) block copolymer. The resulting pH- and thermo-sensitive SMO-PCLA-PEG-PCLA-SMO block copolymer solution did not form a gel at high pH (pH 8.0) or at increased temperatures (ca. 70 degrees C), but did form a stable gel under physiological conditions (pH 7.4 and 37 degrees C). The degradation rate of the pH- and thermo-sensitive block copolymer decreased substantially compared with the control block copolymer of PCLA-PEG-PCLA, due to the buffering effect of the SMO-PCLA-PEG PCLA-SMO sulfonamide groups on the acidic monomer-induced rapid degradation of PCLA-PEG-PCLA. This suitable sol-gel transition and sustained biodegradability of the pH- dand thermo-sensitive SMO-PCLA-PEG-PCLA-SMO block copolymers resolves two of the major drawbacks associated with thermo-sensitive block copolymers, namely premature gelation and rapid degradation. interestingly, SMO-PCLA-PEG PCLA-SMO showed no evidence of cytotoxicity in vitro. However, subcutaneous injection of the pH- and thermo-sensitive block copolymer solution (20 wt% in PBS at pH 8.0) into Sprague-Dawley (SD) rats resulted in rapid, stable gel formation, with the injected hydrogel being completely degraded in vivo in just 6 weeks. The injected hydrogel in vivo presented a typical acute inflammation within 2 weeks, although chronic inflammation was not observed during the first 6-week period. As such, the pH- and thermo-sensitive hydrogel of the SMO-PCLA-PEG-PCLA-SMO block copolymer is a suitable candidate for use in drug delivery systems and cell therapy. (c) 2006 Elsevier Ltd. All rights reserved. English ELSEVIER SCI LTD IN-VIVO CHARACTERIZATION DELIVERY POLYMERS Biodegradability and biocompatibility of a pH- and thermo-sensitive hydrogel formed from a sulfonamide-modified poly(epsilon-caprolactone-co-lactide)-poly(ethylene glycol)-poly(epsilon-caprolactone-co-lactide) block copolymer Article 10.1016/j.biomaterials.2006.05.038 1 BIOMATERIALS, v.27, no.30, pp.5178 - 5185 BIOMATERIALS 27 30 5178 5185 scie scopus 000240506400004 2-s2.0-33746079628 Engineering, Biomedical Materials Science, Biomaterials Engineering Materials Science Article IN-VIVO CHARACTERIZATION DELIVERY POLYMERS pH and thermo-sensitive hydrogel sulfonamide-modified block copolymer biodegradability biocompatibility