title: Simultaneous determination of theophylline and guaiphenesin by third-derivative ultraviolet spectrophotometry and high-performance liquid chromatography.
abstract: Two methods are described for the simultaneous determination of theophylline and guaiphenesin in combined pharmaceutical dosage forms. The first method depends on third-derivative ultraviolet spectrophotometry, with the zero crossing technique of measurement. Third-derivative amplitudes at 222 and 278 nm were selected for the assay of guaiphenesin and theophylline, respectively. The second method is based on high-performance liquid chromatography on a reversed-phase column using a mobile phase of 0.01 mol dm-3 sodium dihydrogen phosphate-methanol-acetonitrile (8 + 2 + 1) (pH 5.5) with detection at 245 nm. Both methods showed good linearity, precision and reproducibility. The proposed methods were successfully applied to the determination of these drugs in laboratory-prepared mixtures and in capsules or elixir.
authors.affiliation: Department of Medicinal Chemistry, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid.
authors.forename: M H
authors.initials: MH
authors.lastname: Abdel-Hay
authors.forename: M S
authors.initials: MS
authors.lastname: el-Din
authors.forename: M A
authors.initials: MA
authors.lastname: Abuirjeie
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004338:Drug Combinations; D006140:Guaifenesin / Q000032:analysis*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D013806:Theophylline / Q000032:analysis*
chemical_list: D004338:Drug Combinations; D006140:Guaifenesin; D013806:Theophylline