title: Changes in morphology of in situ forming PLGA implant prepared by different polymer molecular weight and its effect on release behavior.
abstract: The effects of polymer molecular weight on drug release behavior would be more complicated from in situ forming implants (ISFIs) that change gradually from liquid to semi-solid or solid after injection. To investigate this phenomenon, three commercially available D,L-lactic acid-co-glycolic acid (PLGA) polymers with molecular weights of 12, 34, and 48 kDa were used to prepare ISFIs containing leuprolide acetate (LA) as a model peptide. The influence of polymer molecular weight on the membrane formation, morphology, and also on their in vitro drug release behavior over a period of 28 days was investigated. Results showed that the amount of drug released over the first 24 h (36% +/- 0.34%) (burst release), for formulation prepared with polymer RG 503H (medium molecular weight, M(w) 34 kDa), was significantly higher than others (p < 0.05). Surface and cross-section morphology of ISFI prepared with medium molecular weight polymer to cellular and spongy-like structure which was in good agreement with the release behavior of LA from it.
authors.affiliation: Department of Biomedical Engineering and Medical Physics, Shahid Beheshiti University (M.C), Tehran, Iran. rastaneh@yahoo.com
authors.forename: Reyhaneh
authors.initials: R
authors.lastname: Astaneh
authors.forename: Mohammad
authors.initials: M
authors.lastname: Erfan
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Moghimi
authors.forename: Hamid
authors.initials: H
authors.lastname: Mobedi
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods*; D003692:Delayed-Action Preparations / Q000737:chemistry / Q000493:pharmacokinetics; D004337:Drug Carriers / Q000737:chemistry* / Q000493:pharmacokinetics*; D019344:Lactic Acid / Q000737:chemistry* / Q000493:pharmacokinetics*; D008970:Molecular Weight; D011100:Polyglycolic Acid / Q000737:chemistry* / Q000493:pharmacokinetics*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry / Q000493:pharmacokinetics; D013499:Surface Properties
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid