title: Biodegradable nanoparticles of amphiphilic triblock copolymers based on poly(3-hydroxybutyrate) and poly(ethylene glycol) as drug carriers.
abstract: New amorphous amphiphilic triblock copolymers of poly(3-hydroxybutyrate)-poly(ethylene glycol)-poly(3-hydroxybutyrate) (PHB-PEG-PHB) were synthesized using the ring-opening copolymerization of beta-butyrolactone monomer. They were characterized by fluorescence, SEM and (1)H NMR. These triblock copolymers can form biodegradable nanoparticles with core-shell structure in aqueous solution. Comparing to the poly(ethylene oxide)-PHB-poly(ethylene oxide) (PEO-PHB-PEO) copolymers, these nanoparticles exhibited much smaller critical micelle concentrations and better drug loading properties, which indicated that the nanoparticles were very suitable for delivery carriers of hydrophobic drugs. The drug release profile monitored by fluorescence showed that the release of pyrene from the PHB-PEG-PHB nanoparticles exhibited the second-order exponential decay behavior. The initial biodegradation rate of the PHB-PEG-PHB nanoparticles was related to the enzyme amount, the initial concentrations of nanoparticle dispersions and the PHB block length. The biodegraded products detected by (1)H NMR contained 3HB monomer, dimer and minor trimer, which were safe to the body.
authors.affiliation: State Key Laboratory of Chinese Medicine and Molecular Pharmacology, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, PR China. chengcheng510@yahoo.com
authors.forename: Cheng
authors.initials: C
authors.lastname: Chen
authors.forename: Chung Him
authors.initials: CH
authors.lastname: Yu
authors.forename: Yin Chung
authors.initials: YC
authors.lastname: Cheng
authors.forename: Peter H F
authors.initials: PH
authors.lastname: Yu
authors.forename: Man Ken
authors.initials: MK
authors.lastname: Cheung
mesh_terms: D020341:Absorbable Implants; D000042:Absorption; D004058:Diffusion; D004337:Drug Carriers / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D004364:Pharmaceutical Preparations / Q000008:administration & dosage* / Q000737:chemistry*; D011091:Polyesters / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D000094122:Polyhydroxybutyrates
chemical_list: D004337:Drug Carriers; D004364:Pharmaceutical Preparations; D011091:Polyesters; D011092:Polyethylene Glycols; C514366:poly(3-hydroxybutyrate)-poly(ethylene glycol)-poly(3-hydroxybutyrate); D000094122:Polyhydroxybutyrates