title: A Robust Liquid Chromatographic Method for Confirmation of Drug Stability of Azithromycin in Bulk Samples, Tablets and Suspensions.
abstract: A simple, isocratic and robust RP-HPLC method for the analysis of azithromycin was developed, validated and applied for the analysis of bulk samples, tablets and suspensions. The optimum chromatographic conditions for separation were established as a mobile phase comprised of acetonitrile-0.1 M KH₂PO₄ pH 6.5-0.1 M tetrabutyl ammonium hydroxide pH 6.5-water (25:15:1:59v/v/v/v) delivered at a flow rate of 1.0 mL/min. The stationary phase consisted of reverse-phase XTerra®(250 mm × 4.6 mm i.d., 5 µm particle size) maintained at a temperature of 43 °C with a UV detection at 215 nm. The method was found to be linear in the range 50%-150% (r² = 0.997). The limits of detection and quantification were found to be 0.02% (20 µg) and 0.078% (78 µg), respectively, with a 100.7% recovery of azithromycin. Degradation products of azithromycin in acidic and oxidative environments at 37 °C were resolved from the active pharmaceutical ingredient and thus the method is fit for the purpose of drug stability confirmation.
authors.affiliation: Department of Pharmaceutical Chemistry, University of Nairobi, Off Ngong Road, Nairobi, P.O. Box 19676-00202 Nairobi, Kenya. alex.okaru@gmail.com.
authors.forename: Alex O
authors.initials: AO
authors.lastname: Okaru
authors.affiliation: Department of Pharmaceutical Chemistry, University of Nairobi, Off Ngong Road, Nairobi, P.O. Box 19676-00202 Nairobi, Kenya. koabuga@uonbi.ac.ke.
authors.forename: Kennedy O
authors.initials: KO
authors.lastname: Abuga
authors.affiliation: Department of Pharmaceutical Chemistry, University of Nairobi, Off Ngong Road, Nairobi, P.O. Box 19676-00202 Nairobi, Kenya. franco.kamau@uonbi.ac.ke.
authors.forename: Franco N
authors.initials: FN
authors.lastname: Kamau
authors.affiliation: Department of Pharmaceutical Chemistry, University of Nairobi, Off Ngong Road, Nairobi, P.O. Box 19676-00202 Nairobi, Kenya. snndwigah@uonbi.ac.ke.
authors.forename: Stanley N
authors.initials: SN
authors.lastname: Ndwigah
authors.affiliation: Chemisches und Veterinäruntersuchungsamt (CVUA) Karlsruhe, Weissenburger Straße 3, 76187 Karlsruhe, Germany. lachenmeier@web.de.
authors.forename: Dirk W
authors.initials: DW
authors.lastname: Lachenmeier
keywords: HPLC; azithromycin; degradation products; drug stability; isocratic; robust