title: Stabilization and encapsulation of a staphylokinase variant (K35R) into poly(lactic-co-glycolic acid) microspheres.
abstract: The aim of this study is to prepare poly(lactic-co-glycolic acid) (PLGA) microspheres containing a staphylokinase variant K35R (DGR) with purpose of preserving the protein stability during both encapsulation and drug release. DGR-loaded microspheres are fabricated using a double-emulsion solvent extraction technique. Prior to encapsulation, the effect of ultrasonication emulsification of DGR solutions with methylene chloride on protein recovery was investigated. Moderate ultrasonic treatment of aqueous DGR/dichloromethane mixtures caused approximately 84% DGR aggregation. Polyvinyl alcohol (PVA) added into aqueous DGR solutions significantly improved DGR recovery to >90%. The effects of co-encapsulated PVA and NaCl in the external aqueous phase on the characteristics of the microspheres were investigated. When 2% PVA was co-encapsulated and 2.5% NaCl was added to the external water phase, DGR encapsulation efficiency was significantly increased from 7.1% to 78.1% and DGR was distributed uniformly throughout the microspheres. In vitro release test showed that DGR was released from PLGA microspheres in a sustained manner over 15 days. A large amount of released DGR was inactive in the absence of co-encapsulated PVA. On the contrary, when 2% PVA was co-encapsulated, the released DGR was almost completely intact within 9 days. In conclusion, PLGA microspheres can be an effective carrier for DGR and form a promising depot system.
authors.affiliation: Key Laboratory of Molecular Medicine, Ministry of Education, Fudan University, 130 Dong-an Road, Shanghai 200032, China.
authors.forename: Jin-Tian
authors.initials: JT
authors.lastname: He
authors.forename: Hua-Bo
authors.initials: HB
authors.lastname: Su
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Li
authors.forename: Xian-Mei
authors.initials: XM
authors.lastname: Tao
authors.forename: Wei
authors.initials: W
authors.lastname: Mo
authors.forename: Hou-Yan
authors.initials: HY
authors.lastname: Song
mesh_terms: D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D004795:Enzyme Stability; D005079:Excipients / Q000737:chemistry; D019344:Lactic Acid / Q000737:chemistry*; D008666:Metalloendopeptidases / Q000737:chemistry*; D008752:Methylene Chloride / Q000737:chemistry; D008863:Microspheres; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D011142:Polyvinyl Alcohol / Q000737:chemistry; D011489:Protein Denaturation; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D013678:Technology, Pharmaceutical / Q000379:methods; D013997:Time Factors; D014465:Ultrasonics
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005079:Excipients; D011108:Polymers; D012997:Solvents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D008752:Methylene Chloride; D011142:Polyvinyl Alcohol; D008666:Metalloendopeptidases; C022653:auR protein, Staphylococcus aureus