title: Solvent mediated microstructures and release behavior of insulin from pH-sensitive nanoparticles.
abstract: The insulin loaded nanoparticles composed of poly (lactic-co-glycolic acid) (PLGA) and hydroxypropyl methylcellulose phthalate (HP55) were prepared via the emulsions solvent diffusion method with two different solvents, namely, DMSO and acetone/water. The microstructures of the nanoparticles were studied by the solubility parameters theory, DSC, FTIR, and the nitrogen adsorption technique. Phase-separated PLGA domains were observed from the nanoparticles prepared with both types of solvents. Mesopores were observed from the nanoparticles prepared with DMSO as the solvent and almost did not exist with acetone/water. An in vitro drug release study showed that the pH-sensitivity of nanoparticles was not only attributed to the pH-dependent dissolubility of HP55 but also to the internal microstructure. The formation of mesopores accelerated the release of insulin, leading to no obvious pH-sensitivity of the nanoparticles prepared with DMSO. However, for the nanoparticles prepared with acetone/water, the release of insulin was pH-dependent. The results demonstrated that solvents played an important role in affecting the microstructures of nanoparticles, which influenced markedly the insulin release behavior.
authors.affiliation: School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, PR China.
authors.forename: Zhi Min
authors.initials: ZM
authors.lastname: Wu
authors.forename: Xin Dong
authors.initials: XD
authors.lastname: Guo
authors.forename: Li Juan
authors.initials: LJ
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Jiang
authors.forename: Li
authors.initials: L
authors.lastname: Ling
authors.forename: Yu
authors.initials: Y
authors.lastname: Qian
authors.forename: Yun
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000096:Acetone / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004337:Drug Carriers / Q000138:chemical synthesis*; D004655:Emulsions / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D019344:Lactic Acid / Q000737:chemistry*; D008747:Methylcellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D016062:Porosity; D012997:Solvents / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D014867:Water / Q000737:chemistry
chemical_list: D004337:Drug Carriers; D004655:Emulsions; D007328:Insulin; D012997:Solvents; D014867:Water; D000096:Acetone; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D008747:Methylcellulose; C053309:hydroxypropyl methylcellulose phthalate; D004121:Dimethyl Sulfoxide