title: Extended release lipophilic indomethacin microspheres: formulation factors and mathematical equations fitted drug release rates.
abstract: Extended release liphophilic microspheres of indomethacin were prepared using cetostearyl alcohol (CsA), stearyl alcohol (SA) and cetyl alcohol (CA) in the various drug-lipid ratios. The release of indometacin was studied on the basis of USP criteria and the effects of drug-lipid ratio, the size of microspheres and carboxymethylcellulose sodium (CMC-Na) added as a hydrophilic polymer on the drug release were investigated. In vitro dissolution studies were performed using USP XXIII apparatus I at pH 6.2. Release profiles were evaluated according to first order, Higuchi square root of time and Hixson-Crowell cube root models. The best fit was found with the square root of time model (r2=0.991) for the microspheres (125-250 microm) prepared in 1:4:1 drug-lipid-copolymer ratio using stearyl alcohol. With a further regression analysis, an excellent equation (Release%=-10.721+42.549*square root of (t)-4.027*t) was developed for empirical drug estimation (r2=0.998).
authors.affiliation: Department of Biopharmaceutics and Pharmacokinetics, Faculty of Pharmacy, University of Ege, 35100 Bornova, Izmir, Turkey. karasulue@pharm.ege.edu.tr
authors.forename: Ercüment
authors.initials: E
authors.lastname: Karasulu
authors.forename: H
authors.initials: H
authors.lastname: Yeşim Karasulu
authors.forename: Gökhan
authors.initials: G
authors.lastname: Ertan
authors.forename: Levent
authors.initials: L
authors.lastname: Kirilmaz
authors.forename: Tamer
authors.initials: T
authors.lastname: Güneri
mesh_terms: D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations / Q000737:chemistry / Q000493:pharmacokinetics; D007213:Indomethacin / Q000737:chemistry* / Q000493:pharmacokinetics*; D008863:Microspheres; D008962:Models, Theoretical
chemical_list: D003692:Delayed-Action Preparations; D007213:Indomethacin