title: Flow-injection spectrophotometric determination of azithromycin in pharmaceutical formulations using p-chloranil in the presence of hydrogen peroxide.
abstract: A flow-injection (FI) spectrophotometric procedure exploiting merging zones is proposed for the determination of azithromycin in pharmaceutical formulations. The method is based on the reaction of azithromycin with tetrachloro-p-benzoquinone (p-chloranil) accelerated by hydrogen peroxide and conducted in a methanol medium, producing a purple-red color compound (lambda(max) = 540 nm). The FI system and the experimental conditions were optimized using a multivariate method. Beer's law is obeyed in a concentration range of 50 - 1600 microg mL(-1) with an excellent correlation coefficient (r = 0.9998). The detection limit and the quantification limit were 6.6 and 22.1 microg mL(-1), respectively. No interference was observed from the common excipients, and the recoveries were within 98.6 to 100.4%. The procedure was applied to the determination of azithromycin in pharmaceuticals with a high sampling rate (65 samples h(-1)). The results obtained by the proposed method were in good agreement with those obtained by the comparative method at 95% confidence level.
authors.affiliation: São Paulo State University-UNESP, Institute of Chemistry of Araraquara, Araraquara, SP, Brazil.
authors.forename: José Luiz
authors.initials: JL
authors.lastname: Rufino
authors.forename: Helena Redigolo
authors.initials: HR
authors.lastname: Pezza
authors.forename: Leonardo
authors.initials: L
authors.lastname: Pezza
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis*; D017963:Azithromycin / Q000032:analysis*; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D002703:Chloranil / Q000737:chemistry*; D017022:Flow Injection Analysis / Q000379:methods*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013053:Spectrophotometry / Q000379:methods*; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D002703:Chloranil; D017963:Azithromycin; D006861:Hydrogen Peroxide