title: Effects of lactide monomer on the hydrolytic degradation of poly(lactide-co-glycolide) 85L/15G.
abstract: The hydrolytic degradation of oriented poly(L-lactide-co-glycolide) 85 L/15 G (PLGA 85/15) sample materials with various amounts of lactide monomer was monitored in vitro at 37 °C. The materials were manufactured from medical grade PLGA 85/15 by a two-step melt extrusion-die drawing process. Results showed that the hydrolytic degradation rate depended highly on the lactide monomer content, which in turn influenced the retention of mechanical properties, mass loss, crystallinity, and dimensional stability. Even small quantities of lactide monomer (0.05-0.20 wt%) affected especially the retention of mechanical properties, which started to decline rapidly upon the inherent viscosity reaching 0.6-0.8 dl/g due to hydrolytic degradation. Based on our hydrolytic degradation data, we constructed a simplified mathematical model of degradation-related strength retention and recommend it as a functional quality control tool for melt-processed biodegradable medical devices manufactured from poly(L-lactide-co-glycolide) 85 L/15 G.
authors.affiliation: Department of Biomedical Engineering, Tampere University of Technology, Hermiankatu 12, PO Box 692, FI-33101 Tampere, Finland. kaarlo.paakinaho@tut.fi
authors.forename: K
authors.initials: K
authors.lastname: Paakinaho
authors.forename: H
authors.initials: H
authors.lastname: Heino
authors.forename: J
authors.initials: J
authors.lastname: Väisänen
authors.forename: P
authors.initials: P
authors.lastname: Törmälä
authors.forename: M
authors.initials: M
authors.lastname: Kellomäki
mesh_terms: D004146:Dioxanes / Q000737:chemistry*; D005720:Gamma Rays; D006868:Hydrolysis; D019344:Lactic Acid / Q000737:chemistry*; D055595:Mechanical Phenomena; D008970:Molecular Weight; D044367:Phase Transition; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D013696:Temperature
chemical_list: D004146:Dioxanes; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C091880:dilactide