title: Analysis of degradation data of poly(l-lactide-co-l,d-lactide) and poly(l-lactide) obtained at elevated and physiological temperatures using mathematical models.
abstract: The degradation of resorbable polymeric devices often takes months to years. Accelerated testing at elevated temperatures is an attractive but controversial technique. The purposes of this paper include: (a) to provide a summary of the mathematical models required to analyse accelerated degradation data and to indicate the pitfalls of using these models; (b) to improve the model previously developed by Han and Pan; (c) to provide a simple version of the model of Han and Pan with an analytical solution that is convenient to use; (d) to demonstrate the application of the improved model in two different poly(lactic acid) systems. It is shown that the simple analytical relations between molecular weight and degradation time widely used in the literature can lead to inadequate conclusions. In more general situations the rate equations are only part of a complete degradation model. Together with previous works in the literature, our study calls for care in using the accelerated testing technique.
authors.affiliation: Department of Engineering, University of Leicester, UK.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Han
authors.forename: Jingzhe
authors.initials: J
authors.lastname: Pan
authors.forename: Fraser
authors.initials: F
authors.lastname: Buchanan
authors.forename: Neill
authors.initials: N
authors.lastname: Weir
authors.forename: David
authors.initials: D
authors.lastname: Farrar
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008962:Models, Theoretical; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; C033616:poly(lactide)