title: Synthesis of a novel PEG-block-poly(aspartic acid-stat-phenylalanine) copolymer shows potential for formation of a micellar drug carrier.
abstract: A novel functionalised copolymer with three polymeric components, poly(ethylene glycol)-block-poly(aspartic acid-stat-phenylalanine), PEG-P(asp-phe), was synthesised and investigated for its potential to form micelles via ionic interactions with a model water-soluble drug, diminazene aceturate. Drug-free solutions of structurally related PEG-P(asp-phe) 5:6:4 and PEG-P(asp-phe) 5:4:6 copolymers indicated polymeric aggregation into micellar-type constructs. The size of PEG-P(asp-phe) 5:6:4 micelles was found to be pH and drug content-dependent. The drug-loaded systems existed as discreet units and were fairly uniform in size and shape. More drug could be included in the PEG-P(asp-phe) 5:6:4 micelles as compared to if only interaction with carboxyl groups from aspartic acid units was responsible for micelle formation, indicating the augmentative role of phenylalanine moieties in drug-incorporation. The slower in vitro drug release from PEG-P(asp-phe) 5:6:4 micelles as compared to PEG-Pasp (AB) micelles indicated the role of the phenylalanine moiety in controlling drug release. This study, therefore, confirmed the potential of a novel tri-component copolymer structure, PEG-P(asp-phe), for the formation of polyionic micelles for drug delivery.
authors.affiliation: School of Pharmaceutical Sciences, University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: K
authors.initials: K
authors.lastname: Prompruk
authors.forename: T
authors.initials: T
authors.lastname: Govender
authors.forename: S
authors.initials: S
authors.lastname: Zhang
authors.forename: C D
authors.initials: CD
authors.lastname: Xiong
authors.forename: S
authors.initials: S
authors.lastname: Stolnik
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003692:Delayed-Action Preparations; D004133:Diminazene / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000737:chemistry; D004337:Drug Carriers / Q000138:chemical synthesis* / Q000737:chemistry; D016503:Drug Delivery Systems; D007202:Indicators and Reagents; D008823:Micelles; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D010649:Phenylalanine / Q000737:chemistry; D011092:Polyethylene Glycols / Q000138:chemical synthesis* / Q000737:chemistry; D012542:Scattering, Radiation
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D007202:Indicators and Reagents; D008823:Micelles; C493635:polyethylene glycol-block-polyaspartic acid; D011092:Polyethylene Glycols; D010649:Phenylalanine; C003915:diminazene aceturate; D004133:Diminazene