title: Microbiological assay for azithromycin in pharmaceutical formulations.
abstract: The validation of a microbiological assay, applying the cylinder-plate method, for the determination of the antibiotic azithromycin is described. Using a strain of Micrococcus luteus ATCC 9341 as the test organism, azithromycin at concentrations ranging from 0.1 to 0.4 microgml(-1) could be measured in capsules and suspensions. A prospective validation of the method showed that it was linear (r=0.998), precise (RSD=1.40-capsules; RSD=1.19-powder for suspension and RSD=1.73-oral suspension) and accurate (it measured the added quantities). We conclude that the microbiological assay is satisfactory for quantitation of in vitro antibacterial activity of azithromycin.
authors.affiliation: Departamento de Produção e Controle de Qualidade de Medicamentos, Universidade Federal do Rio Grande do Sul, Faculdade de Farmácia, Av. Ipiranga, 2752, -RS 90610-000, Porto Alegre, Brazil. anarita_breier@hotmail.com
authors.forename: A R
authors.initials: AR
authors.lastname: Breier
authors.forename: C V
authors.initials: CV
authors.lastname: Garcia
authors.forename: T P
authors.initials: TP
authors.lastname: Oppe
authors.forename: M
authors.initials: M
authors.lastname: Steppe
authors.forename: E E S
authors.initials: EE
authors.lastname: Schapoval
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017963:Azithromycin / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D016982:Micrococcus luteus / Q000187:drug effects*; D015203:Reproducibility of Results
chemical_list: D000900:Anti-Bacterial Agents; D017963:Azithromycin