title: Generic nonextractive spectrophotometric method for determination of 4-quinolone antibiotics by formation of ion-pair complexes with beta-naphthol.
abstract: This paper describes the development of a generic spontaneous nonextractive spectrophotometric method for determination of 13 pharmaceutically important 4-quinolone antibiotics. The method was based on the formation of yellow-colored water-soluble ion-pair complexes between 2% (w/v) beta-naphthol reagent and each of the studied drugs in sulfuric acid medium at room temperature. The formed ion-pair chromogens have maximum absorption peaks in the range of 365-391 nm. The concentrations of the reagents and the experimental conditions affecting the reaction were optimized. Under the optimum conditions, linear relationships with good linear coefficients (0.9987-0.9995) were found between the absorbance and concentration of the investigated drugs in the range of 10-350 microg/mL. The assay limits of detection and quantitation were 1-9.9 and 3.4-32.9 microg/mL, respectively. The precision of the method was satisfactory; the values of relative standard deviations did not exceed 2%. The proposed method was successfully applied to the analysis of the investigated drugs in pure and pharmaceutical dosage forms with good accuracy and precision; the percentages of label claim ranged from 97.8-102.8 +/- 0.35-1.60%. The results obtained by the proposed spectrophotometric method were comparable with those obtained by the official or reported methods. The proposed method is superior to all the previously reported ion-pair formation-based methods in terms of simplicity because it did not involve extraction procedures for the ion-pair complex. Therefore, this method might be recommended for routine use in quality control laboratories for analysis of the investigated 4-quinolone antibiotics in their pure forms, as well as in pharmaceutical dosage forms.
authors.affiliation: Assiut University, Faculty of Pharmacy, Department of Pharmaceutical Analytical Chemistry, Assiut 71526, Egypt. iadarwish@yahoo.com
authors.forename: Ibrahim A
authors.initials: IA
authors.lastname: Darwish
authors.forename: Ibrahim H
authors.initials: IH
authors.lastname: Refaat
authors.forename: Hassan F
authors.initials: HF
authors.lastname: Askal
authors.forename: Mostafa A
authors.initials: MA
authors.lastname: Marzouq
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis*; D002138:Calibration; D004304:Dosage Forms; D005079:Excipients; D007202:Indicators and Reagents; D009284:Naphthols / Q000737:chemistry*; D015363:Quinolones / Q000032:analysis*; D012015:Reference Standards; D015203:Reproducibility of Results; D012996:Solutions; D013464:Sulfuric Acids / Q000737:chemistry; D013607:Tablets
chemical_list: D000900:Anti-Bacterial Agents; D004304:Dosage Forms; D005079:Excipients; D007202:Indicators and Reagents; D009284:Naphthols; D015363:Quinolones; D012996:Solutions; D013464:Sulfuric Acids; D013607:Tablets; C033158:sulfuric acid; C028405:2-naphthol