title: Controlled delivery of a hydrophilic drug from a biodegradable microsphere system by supercritical anti-solvent precipitation technique.
abstract: The purpose of this study was to prepare microspheres loaded with hydrophilic drug, bupivacaine HCl using poly(D,L-lactic-co-glycolic acid) (PLGA) and poly(L-lactic acid) (PLLA). Microspheres were prepared with varying the PLGA/PLLA ratio with two different levels of bupivacaine HCl (5 and 10%) using a supercritical anti-solvent (SAS) technique. Microspheres ranging from 4-10 microm in geometric mean diameter could be prepared, with high loading efficiency. Powder X-ray diffraction (PXRD) revealed that bupivacaine HCl retained its crystalline state within the polymer and was present as a dispersion within the polymer phase after SAS processing. The release of bupivacaine HCl from biodegradable polymer microspheres was rapid up to 4 h, thereafter bupivacaine HCl was continuously and slowly released for at least 7 days according to the PLGA/PLLA ratio and the molecular weight of PLLA.
authors.affiliation: National Research Lab of Pharmaceutical Technology, College of Pharmacy, Chungnam National University, Daejeon, Korea.
authors.forename: S
authors.initials: S
authors.lastname: Lee
authors.forename: M S
authors.initials: MS
authors.lastname: Kim
authors.forename: J S
authors.initials: JS
authors.lastname: Kim
authors.forename: H J
authors.initials: HJ
authors.lastname: Park
authors.forename: J S
authors.initials: JS
authors.lastname: Woo
authors.forename: B C
authors.initials: BC
authors.lastname: Lee
authors.forename: S J
authors.initials: SJ
authors.lastname: Hwang
mesh_terms: D020341:Absorbable Implants; D001672:Biocompatible Materials / Q000737:chemistry; D002045:Bupivacaine / Q000008:administration & dosage*; D011232:Chemical Precipitation; D003692:Delayed-Action Preparations / Q000008:administration & dosage; D004339:Drug Compounding / Q000379:methods; D006851:Hydrochloric Acid / Q000737:chemistry; D019344:Lactic Acid / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D011091:Polyesters; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; D003692:Delayed-Action Preparations; D011091:Polyesters; D011108:Polymers; D012997:Solvents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C033616:poly(lactide); D006851:Hydrochloric Acid; D002045:Bupivacaine