title: Determination of low plasma timolol concentrations following topical application of timolol eye drops in humans by high-performance liquid chromatography with electrochemical detection.
abstract: A simple and sensitive high-performance liquid chromatographic assay was developed for determination of timolol in human plasma following administration of two drops of a 5% timolol ophthalmic solution. A 4% butyl alcohol-hexane extract of an alkalized sample of plasma was chromatographed on a reversed-phase column and the components in the column effluent were monitored by coulometric detection. The extraction efficiency of timolol was 69.02 +/- 4.16% (mean +/- S.D.) and its detection limit was 107.2 pg/ml. The effect of mobile phase pH, buffer concentration and the working potential of the detector on column performance and the electrochemical response are described.
authors.affiliation: Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-6620.
authors.forename: H
authors.initials: H
authors.lastname: He
authors.forename: T I
authors.initials: TI
authors.lastname: Edeki
authors.forename: A J
authors.initials: AJ
authors.lastname: Wood
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004563:Electrochemistry; D006801:Humans; D009883:Ophthalmic Solutions / Q000008:administration & dosage*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013999:Timolol / Q000008:administration & dosage / Q000097:blood*
chemical_list: D009883:Ophthalmic Solutions; D013999:Timolol