title: Smart nanoparticles based on pullulan-g-poly(N-isopropylacrylamide) for controlled delivery of indomethacin.
abstract: Double hydrophilic thermo-responsive pullulan-g-poly(N-isopropylacrylamide) (P-g-pNIPAM) copolymers with two different molecular weight of thermosensitive grafts were synthesized and used for preparation of indomethacin-loaded nanoparticles by dialysis and nanoprecipitation method. The polymers form aggregates in aqueous solution at a concentration of 10g/L, above their critical aggregation concentration (3.36g/L) and below the lower critical solution temperature (LCST). After indomethacin loading, nanoparticles with compact and uniform structure were formed below the LCST. The effects of copolymer composition, concentration, and the feed polymer/drug ratio on the particle size, drug loading content (DLC) and entrapment efficiency (EE) were investigated. DLC increased with drug feeding, reaching a maximum value of 40% at the ratios of 1/1. Smaller particles (145nm) with narrower size distribution were obtained from polymer with a higher molecular weight of pNIPAM grafts. FT-IR and1H NMR spectra proved that the main driven force for the aggregation was the hydrogen bonding between indomethacin and the pNIPAM side chains of copolymer. The indomethacin release rate from nanoparticles was influenced by temperature, because of the dissociation of the hydrogen bonds at high temperatures, the degree of drug loading, and the pH of the release media.
authors: "Petru Poni" Institute of Macromolecular Chemistry, Department of Natural Polymers, Bioactive and Biocompatible Materials, Gr. Ghica Voda 41A, 700487 Iasi, Romania.
authors: Marieta
authors: M
authors: Constantin
authors: "Petru Poni" Institute of Macromolecular Chemistry, Department of Natural Polymers, Bioactive and Biocompatible Materials, Gr. Ghica Voda 41A, 700487 Iasi, Romania.
authors: Sanda
authors: S
authors: Bucătariu
authors: "Petru Poni" Institute of Macromolecular Chemistry, Department of Natural Polymers, Bioactive and Biocompatible Materials, Gr. Ghica Voda 41A, 700487 Iasi, Romania.
authors: Iuliana
authors: I
authors: Stoica
authors: "Petru Poni" Institute of Macromolecular Chemistry, Department of Natural Polymers, Bioactive and Biocompatible Materials, Gr. Ghica Voda 41A, 700487 Iasi, Romania. Electronic address: ghefun@icmpp.ro.
authors: Gheorghe
authors: G
authors: Fundueanu
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D003692:Delayed-Action Preparations / Q000138:chemical synthesis*; D004337:Drug Carriers / Q000138:chemical synthesis*; D004339:Drug Compounding; D065546:Drug Liberation; D005936:Glucans / Q000737:chemistry*; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D007213:Indomethacin / Q000737:chemistry*; D007700:Kinetics; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D013696:Temperature
chemical_list: D000180:Acrylic Resins; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005936:Glucans; C052970:poly-N-isopropylacrylamide; C009109:pullulan; D007213:Indomethacin
keywords: Drug release; Graft copolymers; Indomethacin; Nanoparticles; Pullulan; poly(N-isopropylacrylamide)