title: Determination of meloxicam using europium sensitized luminescence in the presence of co-luminescence reagents.
abstract: A sensitive time-resolved luminescence method for the determination of meloxicam (MX) in methanol and in aqueous solution is described. The method is based on the luminescence sensitization of europium (Eu(3+)) by formation of ternary complex with MX in the presence of 1,10-phenanthroline as coligand, Tween-80 as surfactant and gadolinium ion as a co-luminescence reagent. The signal for Eu-MX-1,10-phenanthroline is monitored at λ(ex) = 360 nm and λ(em) = 620 nm. Optimum conditions for the formation of the complex in aqueous system were 0.01 M TRIS buffer, pH 8.0, 1,10-phenanthroline (6.0 × 10(-6) M), Gd(3+) (7.0 × 10(-6) M), Tween-80 (0.28%) and 1.75 mM of Eu(3+) which allows the determination of 20-800 ppb of MX with limit of detection (LOD) of 7 ppb. The relative standard deviations of the method range between 0.1 and 1.1% indicating excellent reproducibility of the method. The proposed method was successfully applied for the assay of MX in pharmaceutical formulations, plasma and in urine samples. Average recoveries of 99.8 ± 1.1%, 100.2 ± 0.9% and 100.9 ± 1.1% were obtained for MX in tablet, plasma and urine sample respectively.
authors.affiliation: Department of Chemistry, College of Science, Sultan Qaboos University, Al-Khod 123, Box 36, Muscat, Sultanate of Oman. alkindy@squ.edu.om
authors.forename: Salma Muhamed Z
authors.initials: SM
authors.lastname: Al-Kindy
authors.forename: Salim K
authors.initials: SK
authors.lastname: Al-Habsy
authors.forename: Fakhr Eldin O
authors.initials: FE
authors.lastname: Suliman
authors.forename: Haidar A J
authors.initials: HA
authors.lastname: Al-Lawati
mesh_terms: D005063:Europium / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents / Q000737:chemistry; D008163:Luminescent Measurements / Q000379:methods*; D000077239:Meloxicam; D000432:Methanol / Q000737:chemistry; D013607:Tablets; D013843:Thiazines / Q000032:analysis* / Q000097:blood / Q000737:chemistry* / Q000652:urine; D013844:Thiazoles / Q000032:analysis* / Q000097:blood / Q000737:chemistry* / Q000652:urine; D014867:Water / Q000737:chemistry
chemical_list: D007202:Indicators and Reagents; D013607:Tablets; D013843:Thiazines; D013844:Thiazoles; D014867:Water; D005063:Europium; D000077239:Meloxicam; D000432:Methanol