title: Spectrophotometric determination of piroxicam and tenoxicam in pharmaceutical formulations using alizarin.
abstract: New spectrophotometric procedures have been established for the quantitation of piroxicam and tenoxicam. The procedures are based on the reaction between the examined drug and alizarin (I), alizarin red S (II), alizarin yellow G (III) or quinalizarin (IV) producing ion-pair complexes which can be measured at the optimum wavelength. The optimization of the reaction conditions is investigated. Beer's law is obeyed in the concentration ranges 0.05-2.40 microg ml(-1), whereas optimum concentration as adopted from Ringbom plots was 0.12-2.25 microg ml(-1). The molar absorptivity, Sandell sensitivity, detection and quantification limits are also calculated. The correlation coefficient was >/=0.9990 (n=10) with a relative standard deviation (R.S.D.) of </=1.2, for ten determinations of 1.0 microg ml(-1). The methods are successfully applied to the determination of piroxicam and tenoxicam in their pharmaceutical formulations.
authors.affiliation: Chemistry Department, Faculty of Science, Benha University, Benha, Egypt.
authors.forename: Alaa S
authors.initials: AS
authors.lastname: Amin
mesh_terms: D000880:Anthraquinones / Q000737:chemistry; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D010894:Piroxicam / Q000031:analogs & derivatives* / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012997:Solvents / Q000737:chemistry; D013053:Spectrophotometry; D013696:Temperature; D013997:Time Factors
chemical_list: D000880:Anthraquinones; D000894:Anti-Inflammatory Agents, Non-Steroidal; D012997:Solvents; D010894:Piroxicam; C010078:alizarin; C032801:tenoxicam