title: Insulin nanoparticle preparation and encapsulation into poly(lactic-co-glycolic acid) microspheres by using an anhydrous system.
abstract: Insulin has been encapsulated in poly(lactic-co-glycolic acid) (PLGA) microspheres by solid-in-oil-in-oil (S/O/O) emulsion technique using DMF/corn oil as new solvent pairs. To get better encapsulation efficiency, insulin nanoparticles were prepared by the modified isoelectric point precipitation method so that it had good dispersion in the inner oil phase. The resulting microspheres had drug loading of 10% (w/w), while the encapsulation efficiency could be up to 90-100%. And the insulin release from the microspheres could last for 60 days. Microspheres encapsulated original insulin with the same method had lower encapsulation efficiency, and shorter release period. Laser scanning confocal microscopy indicated the insulin nanoparticle and original insulin had different distribution in microspheres. The results suggested that using insulin nanoparticle was better than original insulin for microsphere preparation by S/O/O method. Study about the secondary structure of insulin by Fourier transform infrared spectroscopy (FTIR) indicated high insulin structural integrity during the process. In vivo test showed insulin in microspheres retained its bioactivity. In addition, cytotoxicity evaluation by the MTT assay has proved that no extra toxicity was introduced into the microspheres during the emulsion process.
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
authors.forename: Yadong
authors.initials: Y
authors.lastname: Han
authors.forename: Huayu
authors.initials: H
authors.lastname: Tian
authors.forename: Pan
authors.initials: P
authors.lastname: He
authors.forename: Xuesi
authors.initials: X
authors.lastname: Chen
authors.forename: Xiabin
authors.initials: X
authors.lastname: Jing
mesh_terms: D000818:Animals; D003314:Corn Oil / Q000737:chemistry; D003692:Delayed-Action Preparations; D004126:Dimethylformamide; D004655:Emulsions; D005260:Female; D005559:Formamides / Q000737:chemistry; D007004:Hypoglycemic Agents / Q000008:administration & dosage* / Q000633:toxicity; D007328:Insulin / Q000008:administration & dosage* / Q000633:toxicity; D007526:Isoelectric Point; D019344:Lactic Acid / Q000737:chemistry*; D018613:Microscopy, Confocal; D008863:Microspheres; D053758:Nanoparticles; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D017433:Protein Structure, Secondary; D051381:Rats; D017208:Rats, Wistar; D012997:Solvents / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D003692:Delayed-Action Preparations; D004655:Emulsions; D005559:Formamides; D007004:Hypoglycemic Agents; D007328:Insulin; D012997:Solvents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D003314:Corn Oil; D004126:Dimethylformamide