title: Biodegradable microparticulates of beta-estradiol: preparation and in vitro characterization.
abstract: Beta-estradiol has been recommended for the long-term therapy of osteoporosis and its oral formulations are subjected to intensive first pass metabolism. The present investigation was aimed at preparing and characterizing biodegradable microparticles of beta-estradiol with polymers such as PLA, PLGA 85/15, PLGA 75/25, and their mixtures. The microparticles were prepared by solvent evaporation method using methylene chloride as a solvent and polyvinyl alcohol as a surfactant. The drug-polymer ratios were 1:3, 1:5, and 1:7. The prepared microparticles (twelve formulations) were tested for encapsulation efficiency and in vitro drug release in 50% methyl alcohol/phosphate buffer pH 7.4. The results showed that the encapsulation efficiency varied from 81 to 100% and the formulation fabricated from PLGA 85/15 (1:3) showed less burst and consistent long time release. This formulation when further characterized displayed irregular spherical shape with an average particle size of 72 microm. The crystallinity of the drug was reduced when investigated using X-ray diffractometry. No chemical interaction between the drug and the polymer was observed as evidenced by FT-IR analysis. The results indicated that beta-estradiol biodegradable microparticles with PLGA 85/15 (1:3) could be a suitable approach for long term therapy of osteoporosis.
authors.affiliation: Faculty of Pharmacy, Kuwait University, Safat, Kuwait. abdel@hsc.edu.kw
authors.forename: Abdel-Azim A
authors.initials: AA
authors.lastname: Zaghloul
authors.forename: Fatima
authors.initials: F
authors.lastname: Mustafa
authors.forename: Afzal
authors.initials: A
authors.lastname: Siddiqu
authors.forename: Mansoor
authors.initials: M
authors.lastname: Khan
mesh_terms: D001673:Biodegradation, Environmental; D002626:Chemistry, Pharmaceutical; D004337:Drug Carriers; D004339:Drug Compounding; D004958:Estradiol / 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*; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D004337:Drug Carriers; D011091:Polyesters; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C033616:poly(lactide); D004958:Estradiol