title: Effect of encapsulating arginine containing molecules on PLGA: a solid-state NMR study.
abstract: Design of polymer-drug composites based on the lactide/glycolic acid often rely on the chemical complementarity between the polymer and functional groups in a pharmaceutical guest. We previously characterised decapeptide (AZD)/poly(D,L-lactide-co-glycolide) (PLGA) film formulations aiming at localising the interacting groups responsible for the changes in the bulk properties of the polymer matrix and understanding the mechanism of stabilisation of the drug into the polymer matrix. The results suggested interactions to occur between the arginine residue in the peptide and the carbonyl end group of the polymer chains. In order to clarify the role of arginine in directing the drug-polymer interactions, arginine and hexapeptide containing arginine were encapsulated in a PLGA 50/50 polymer. Variable temperature T1 rh H measurements and WISE experiments indicated significant changes in the local dynamics of the polymer chains. These effects were enhanced near and above T(g) suggesting the presence of guests promote the appearance of backbone motion of the polymer chains. The localisation of the interactions on the carbonyl groups of the polymer was further confirmed by the WISE experiments.
authors.affiliation: Department of Chemistry, The University of Liverpool, Crown St, Liverpool L69 7ZD, UK.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Guilbaud
authors.forename: Helen
authors.initials: H
authors.lastname: Baker
authors.forename: Brian C
authors.initials: BC
authors.lastname: Clark
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Meehan
authors.forename: Yaroslav Z
authors.initials: YZ
authors.lastname: Khimyak
mesh_terms: D001120:Arginine; D006016:Glycolates; D007477:Ions; D019344:Lactic Acid; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation*; D009842:Oligopeptides; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D013696:Temperature
chemical_list: D006016:Glycolates; D007477:Ions; D009842:Oligopeptides; D011108:Polymers; C031149:glycolic acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D001120:Arginine