title: Effects of formulation parameters on encapsulation efficiency and release behavior of thienorphine loaded PLGA microspheres.
abstract: To develop a long-acting injectable thienorphine biodegradable poly (d, l-lactide-co-glycolide) (PLGA) microsphere for the therapy of opioid addiction, the effects of formulation parameters on encapsulation efficiency and release behavior were studied. The thienorphine loaded PLGA microspheres were prepared by o/w solvent evaporation method and characterized by HPLC, SEM, laser particle size analysis, residual solvent content and sterility testing. The microspheres were sterilized by gamma irradiation (2.5 kGy). The results indicated that the morphology of the thienorphine PLGA microspheres presented a spherical shape with smooth surface, the particle size was distributed from 30.19 ± 1.17 to 59.15 ± 0.67 μm and the drug encapsulation efficiency was influenced by drug/polymer ratio, homogeneous rotation speed, PVA concentration in the water phase and the polymer concentration in the oil phase. These changes were also reflected in drug release. The plasma drug concentration vs. time profiles were relatively smooth for about 25 days after injection of the thienorphine loaded PLGA microspheres to beagle dogs. In vitro and in vivo correlation was established.
authors.affiliation: Beijing Institute of Pharmacology and Toxicology, Beijng, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Yongliang
authors.initials: Y
authors.lastname: Gao
authors.forename: Xingguo
authors.initials: X
authors.lastname: Mei
mesh_terms: D000818:Animals; D002047:Buprenorphine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry / Q000493:pharmacokinetics; D002626:Chemistry, Pharmaceutical / Q000379:methods; D004285:Dogs; D004339:Drug Compounding / Q000379:methods; D019344:Lactic Acid / Q000008:administration & dosage / Q000737:chemistry* / Q000493:pharmacokinetics; D008297:Male; D008863:Microspheres; D009821:Oils / Q000737:chemistry; D010316:Particle Size; D011100:Polyglycolic Acid / Q000008:administration & dosage / Q000737:chemistry* / Q000493:pharmacokinetics; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D012997:Solvents / Q000737:chemistry
chemical_list: D009821:Oils; D012997:Solvents; C512397:thienorphine; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D002047:Buprenorphine