title: Improvement of protein loading and modulation of protein release from poly(lactide-co-glycolide) microspheres by complexation of proteins with polyanions.
abstract: A novel method was proposed to incorporate and modulate protein release from poly(lactide-co-glycolide) (PLGA) microspheres by a modified w/o/w emulsion solvent evaporation technique with poly(methacrylic acid) (PMAA)/insulin complex suspension as the inner aqueous phase instead of the neat protein solution. It was found that a reversible, water-insoluble complex could be formed between PMAA and insulin by electrostatic interactions. A great increase in insulin entrapment efficiency was observed as the PMAA/insulin complex was adopted to prepare PLGA microspheres. A large number of the complex particles adsorbed at the surface of the microspheres, resulting in the more rapid insulin release. The complexation and microencapsulation processes have little effect on insulin bioactivity, which was revealed by examination of the plasma glucose levels of the diabetic rats administrated with the microspheres.
authors.affiliation: Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, PR China. jianghl72@yahoo.com
authors.forename: H L
authors.initials: HL
authors.lastname: Jiang
authors.forename: J F
authors.initials: JF
authors.lastname: Jin
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Hu
authors.forename: K J
authors.initials: KJ
authors.lastname: Zhu
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism; D004339:Drug Compounding / Q000379:methods; D005260:Female; D007328:Insulin / Q000378:metabolism; D008855:Microscopy, Electron, Scanning / Q000379:methods; D008863:Microspheres; D009391:Nephelometry and Turbidimetry; D000071228:Polyelectrolytes; D011098:Polyglactin 910; D011108:Polymers; D011109:Polymethacrylic Acids; D011506:Proteins / Q000737:chemistry*; D051381:Rats; D012995:Solubility; D012996:Solutions
chemical_list: D001786:Blood Glucose; D007328:Insulin; D000071228:Polyelectrolytes; D011098:Polyglactin 910; D011108:Polymers; D011109:Polymethacrylic Acids; D011506:Proteins; D012996:Solutions; C030613:polymethacrylic acid