Determination of low plasma timolol concentrations following topical application of timolol eye drops in humans by high-performance liquid chromatography with electrochemical detection.
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.
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Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-6620.
Edeki
T I
TI
Wood
A J
AJ
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*
D009883:Ophthalmic Solutions; D013999:Timolol