title: Microbiological assay for the determination of azithromycin in ophthalmic solutions.
abstract: The validation of a simple, sensitive and specific agar diffusion bioassay, applying cylinder-plate method, for the determination of the antibiotic azithromycin in ophthalmic solutions is described. Using a strain of Bacillus subtilis ATCC 9372 as the test organism, azithromycin at concentrations ranging from 50.0 to 200.0 microg.mL(-1) could be measured in 1.6667 mg.mL(-1) ophthalmic solutions. A prospective validation of the method showed that the method was linear (r = 0. 999 9) and precise (RSD = 0. 70) and accurate (it measured the added quantities). The results obtained by bioassay method could be statistically calculated by linear parallel model and by means of regression analysis and verified using analysis of variance (ANOVA). We conclude that the microbiological assay is satisfactory for quantification of azithromycin in ophthalmic solutions.
authors.affiliation: Programa de Pós-graduaçaão em Ciências Farmacêuticas, Departamento de Fármacos e Medicamentos, Faculdade de Ciências Farmacêuticas, UNESP, Rodovia Araraquara-Jaú, km 1, Araraquara- SP-CEP 14801-902, Brazil. salgadoh@fcfar.unesp.br
authors.forename: Hérida Regina Nunes
authors.initials: HR
authors.lastname: Salgado
authors.forename: Ana Flávia Ferreira
authors.initials: AF
authors.lastname: Roncari
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000032:analysis* / Q000494:pharmacology; D017963:Azithromycin / Q000008:administration & dosage / Q000032:analysis* / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D009883:Ophthalmic Solutions / Q000737:chemistry; D011786:Quality Control
chemical_list: D000900:Anti-Bacterial Agents; D009883:Ophthalmic Solutions; D017963:Azithromycin