การผลิตพอลิ(แอล-แลกไทด์-โค-ไกลโคไลด์) สำหรับใช้เป็นแผ่นพอลิเมอร์ดูดซึมได้ในทางศัลยกรรมกระดูกขากรรไกร

Abstract

Synthesis, fabrication and properties of poly(L-lactide-co-glycolide) (PLG) copolymer for use as resorbable polymer plates in orthognathic surgery was studied in this research work. The PLG copolymer in the ratio of 82:18 mole % was synthesized via ring-opening bulk polymerization (ROP) at 120 and 130 °C for 96 hours using 0.0175 mole % of liquid tin(II) n-butoxide as initiator. Two differences molecular weights (intrinsic viscosity [] = 1.24 and 2.77 dl/g) were synthesized using the different controlled temperature. PLG copolymer sheets were fabricated using injection molding followed by international standard ASTM D790 in rectangular shape for flexural property testing. In vitro hydrolytic degradation of PLG sheets were tested by immersed in phosphate buffer saline (PBS) solution at pH 7.40  0.2 and maintain at a temperature of 37.0  0.5 °C in an incubator for 84 days. The hydrolytic degradation was followed via the characteristic changes in the degradation periods such as the physical appearances, % weight loss, % water absorption, pH, ratio of copolymer, molecular weight, thermal properties, flexural property and surface topography changes by SEM. The results found that two difference molecular weight of PLG copolymer sheets did not differ significantly between the hydrolytic degradation testing. The PLG copolymer sheets was readily hydrolysable in the aqueous environment and the pH decreased after 84 days, indicating that the hydrolytic reaction taking place produced low molecular weight give acidic degradation products. In comparison, the %weight loss and %water absorption showed that the hydrolytic degradation of PLG copolymer is bulk erosion. This is consistent with SEM images showed that the hydrolytic degradation process takes place bulk erosion rather than on the surface because of many fracture and pore in the cross section. In addition, the change of the ratio of the monomer in PLG copolymer sheet indicate that glycolide unit can be degraded faster than L-lactide unit, which is random chain scission. It was also found that change of degradation time does not affect the morphology of PLG copolymer sheets but affect the percent crystallinity, which affect the mechanical properties.