Extended release lipophilic indomethacin microspheres: formulation factors and mathematical equations fitted drug release rates

• Published in: European journal of pharmaceutical sciences 2003-06, Vol.19 (2), p.99-104
• Main Authors: Karasulu, Ercüment, Yeşim Karasulu, H, Ertan, Gökhan, Kirilmaz, Levent, Güneri, Tamer
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Bones, joints and connective tissue. Antiinflammatory agents; Chemistry, Pharmaceutical; Delayed-Action Preparations - chemistry; Delayed-Action Preparations - pharmacokinetics; Equation; Extended release; General pharmacology; Indomethacin; Indomethacin - chemistry; Indomethacin - pharmacokinetics; Indomethacin microsphere; Kinetic model; Lipophilic microsphere; Medical sciences; Microspheres; Models, Theoretical; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments
• ISSN: 0928-0987; 1879-0720
• DOI: 10.1016/S0928-0987(03)00048-4

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 ( r 2=0.991) for the microspheres (125–250 μm) 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* t −4.027*t ) was developed for empirical drug estimation ( r 2=0.998).