title: Insulin/poly(ethylene glycol)-block-poly(L-lysine) Complexes: Physicochemical Properties and Protein Encapsulation.
abstract: Insulin (INS) was encapsulated into complexes with poly(ethylene glycol)-block-poly(L-lysine) (PEG-b-PLys), which is a polypeptide-based block copolymer (a neutral-cationic block polyelectrolyte). The particular cationic-neutral block copolymer can complex INS molecules in aqueous media via electrostatic interactions. Light-scattering techniques are used to study the complexation process and structure of the hybrid nanoparticles in a series of buffers, as a function of protein concentration. The physicochemical and structural characteristics of the complexes depend on the ionic strength of the aqueous medium, while the concentration of PEG-b-PLys was constant through the series of solutions. As INS concentration increased the size distribution of the complexes decreased, especially at the highest ionic strength. The size/structure of complexes diluted in biological medium indicated that the copolymer imparts stealth properties and colloidal and biological stability to the complexes, features that could in turn affect the clearance properties in vivo. Therefore, these studies could be a rational roadmap for designing the optimum complexes/effective nanocarriers for proteins and peptides.
authors.affiliation: †Department of Pharmaceutical Technology, Faculty of Pharmacy, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, Athens 15771, Greece.|‡Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave, Athens 11635, Greece.
authors.forename: Natassa
authors.initials: N
authors.lastname: Pippa
authors.affiliation: §Institute of Polymers, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria.
authors.forename: Radostina
authors.initials: R
authors.lastname: Kalinova
authors.affiliation: §Institute of Polymers, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria.
authors.forename: Ivaylo
authors.initials: I
authors.lastname: Dimitrov
authors.affiliation: ‡Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave, Athens 11635, Greece.
authors.forename: Stergios
authors.initials: S
authors.lastname: Pispas
authors.affiliation: †Department of Pharmaceutical Technology, Faculty of Pharmacy, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, Athens 15771, Greece.
authors.forename: Costas
authors.initials: C
authors.lastname: Demetzos
mesh_terms: D002214:Capsules; D055598:Chemical Phenomena; D004337:Drug Carriers / Q000737:chemistry*; D007328:Insulin / Q000737:chemistry*; D009994:Osmolar Concentration; D011092:Polyethylene Glycols / Q000737:chemistry*; D011107:Polylysine / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D002214:Capsules; D004337:Drug Carriers; D007328:Insulin; D014867:Water; D011107:Polylysine; D011092:Polyethylene Glycols