title: Development of Recombinant Human Growth Hormone (rhGH) sustained-release microspheres by a low temperature aqueous phase/aqueous phase emulsion method.
abstract: A novel method has been developed to protect Recombinant Human Growth Hormone (rhGH) in poly (lactic-co-glycolic acid) (PLGA) microspheres using an aqueous phase/aqueous phase emulsion and S/O/W multi-emulsion method. This method develops a novel rhGH sustained-release system, which is based on the combination of rhGH-loaded dextran microparticles and PLGA microspheres. The process to fabricate rhGH-loaded dextran microparticles involves an aqueous phase/aqueous phase emulsion system formed at the reduced temperature. RhGH was first dissolved in water together with dextran and polyethylene glycol, followed by stirring at the speed of 2000 rpm for 20-30s at 0°C, and then a freezing process could enable the dextran phase to separate from the continuous PEG phase and rhGH could preferentially be loaded with dextran. The sample after freezing and phase separation was then lyophilized to powder and washed with dichloromethane to remove the PEG. Once loaded in the dextran microparticles (1-4 μm in diameter), rhGH gained resistance to interface tensions and was encapsulated into PLGA microspheres without aggregation thereafter. RhGH released from PLGA microspheres was in a sustained manner with minimal burst and maximally reduced incomplete release in vitro. Single subcutaneous injection of rhGH-loaded PLGA microspheres to rats resulted in a stable plasma concentration for 30 days avoiding the drug concentration fluctuations after multiple injections of protein solutions. In a hypophysectomized rat model, the IGF-1 and bodyweight results showed that there were higher than the levels obtained for the sustained release formulation by W/O/W for 40 days. These results suggest that the microsphere delivery system had the potential to be an injectable depot for sustained-release of the biocompatible protein of rhGH.
authors.affiliation: School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Kang
authors.affiliation: School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Wu
authors.affiliation: School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
authors.forename: Yunpeng
authors.initials: Y
authors.lastname: Cai
authors.affiliation: School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
authors.forename: Mingxin
authors.initials: M
authors.lastname: Xu
authors.affiliation: School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
authors.forename: Mu
authors.initials: M
authors.lastname: He
authors.affiliation: School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. Electronic address: yuanweien@126.com.
authors.forename: Weien
authors.initials: W
authors.lastname: Yuan
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002460:Cell Line; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D003911:Dextrans / Q000737:chemistry; D004337:Drug Carriers / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D004655:Emulsions; D019382:Human Growth Hormone / Q000008:administration & dosage* / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics; D007016:Hypophysectomy; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D019344:Lactic Acid / Q000737:chemistry; D008297:Male; D008863:Microspheres; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000008:administration & dosage* / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics; D013696:Temperature
chemical_list: D003692:Delayed-Action Preparations; D003911:Dextrans; D004337:Drug Carriers; D004655:Emulsions; D011994:Recombinant Proteins; C548904:insulin-like growth factor-1, rat; D019382:Human Growth Hormone; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D007334:Insulin-Like Growth Factor I
keywords: Bioactivity; Microspheres; Recombinant Human Growth Hormone (rhGH); Stability; Sustained-release