title: A novel accelerated in vitro release method to evaluate the release of thymopentin from PLGA microspheres.
abstract: A novel accelerated method of good correlations with "real-time" release to evaluate in vitro thymopentin release from poly (D, L-lactide-co-glycolide) (PLGA) microsphere was developed. Thymopentin-loaded microspheres were made from three types of PLGA, and peptide release was studied in various conditions. Incomplete release of peptide (<60%) from microspheres was found in accelerated testing with two typical release media. This problem was circumvented by adding organic solvents to the release media and varying the temperature in the media heating process. Release media containing three kinds of organic solvents at 50 °C were tested, respectively, and hydro-alcoholic solution was selected for further study. After the surfactant concentration (0.06%, W/V) and ethanol concentration (20%, V/V) were fixed, a gradient heating program, consisting of three stages and each stage with a different temperature, was introduced to enhance the correlations between the short- and long-term release. After adjusting the heating time of each stage, a good correlation (R(2) = 9896, formulation 8 K; R(2) = 0.9898, formulation 13 K; R(2) = 0.9886, formulation 28 K) between accelerated and "real-time" release was obtained. By optimizing the conditions as ethanol concentration and temperature gradients, this accelerated method may be appropriate for similar peptide formulations that not well correlate with "real-time" release.
authors.affiliation: Wuhan General Hospital of Guangzhou Military Command , Wuhan , People's Republic of China .
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Xie
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Li
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Chi
authors.forename: Yanfang
authors.initials: Y
authors.lastname: Yang
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Xingguo
authors.initials: X
authors.lastname: Mei
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage* / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry*; D065546:Drug Liberation; D000431:Ethanol / Q000737:chemistry; D005079:Excipients / Q000737:chemistry; D019344:Lactic Acid / Q000737:chemistry*; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D013501:Surface-Active Agents / Q000737:chemistry; D013678:Technology, Pharmaceutical / Q000379:methods*; D016305:Thymopentin / Q000008:administration & dosage* / Q000737:chemistry; D044366:Transition Temperature
chemical_list: D000276:Adjuvants, Immunologic; D004337:Drug Carriers; D005079:Excipients; D013501:Surface-Active Agents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D000431:Ethanol; D016305:Thymopentin
keywords: Accelerated release; PLGA microspheres; gradient heating program; peptide release; thymopentin