title: Nonhalogenated solvent-based solvent evaporation process useful in preparation of PLGA microspheres.
abstract: The objective of this study was to develop an isopropyl formate-based evaporation process useful in producing poly-D,L-lactide-co-glycolide microspheres. Surprisingly, the evaporating tendency of isopropyl formate was comparable to that of methylene chloride and far better than that of ethyl acetate. After optimization of the isopropyl formate-based process, progesterone was encapsulated into microspheres. Under our conditions, its encapsulation efficiency ranged from 75.1% to 92.6%. Even though all microspheres took spherical geometry, their external and internal morphologies were greatly influenced by progesterone payloads. A GC analysis demonstrated that residual isopropyl formate in various microspheres was 1.8% to 4.0%. Interestingly, progesterone underwent polymorphic transition during the microencapsulation process - the β form was present in microspheres with lower progesterone payloads, whereas the α form predominated over the β one at higher progesterone loads. In terms of human safety and environmental toxicity, isopropyl formate might have an edge over halogenated organic solvents for solvent evaporation.
authors.affiliation: College of Pharmacy, Ewha Womans University , 11-1 Daehyun-dong, Seodaemun-gu, Seoul 120-750 , South Korea.
authors.forename: Jeeyoung
authors.initials: J
authors.lastname: Jang
authors.forename: Hongkee
authors.initials: H
authors.lastname: Sah
mesh_terms: D004337:Drug Carriers / Q000737:chemistry; D004339:Drug Compounding / Q000379:methods*; D005563:Formic Acid Esters / Q000737:chemistry*; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry*; D008863:Microspheres; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011374:Progesterone / Q000008:administration & dosage*; D011372:Progestins / Q000008:administration & dosage*
chemical_list: D004337:Drug Carriers; D005563:Formic Acid Esters; D011372:Progestins; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D011374:Progesterone; C546536:isopropyl formate