The use of stable isotope labeling and liquid chromatography-tandem mass spectrometry techniques to simultaneously determine the oral and ophthalmic bioavailability of timolol in dogs.
J Chromatogr Sci
; 36(4): 163-8, 1998 Apr.
Article
em En
| MEDLINE
| ID: mdl-9563202
ABSTRACT
Assays have been established for the quantitation of timolol and its 13C3- and 2H9-stable-isotope-labeled analogs in plasma and urine using liquid chromatography with atmospheric-pressure chemical-ionization tandem mass spectrometry. For the analysis of urine, underivatized timolol and its labeled analogs are monitored while timolol in plasma is assayed down to concentrations of 0.2 ng/mL after derivatization with phosgene. The great power of this technique is illustrated by simultaneously assaying three different species of timolol in plasma and urine obtained from dogs receiving simultaneous ophthalmic, oral, and intravenous doses of unlabeled and [2H9]- and [13C3]-labeled timolol. Thus, the ophthalmic and oral bioavailabilities of timolol are measured in a single experiment rather than as a three-phase crossover experiment. This approach yields accurate and precise analytical data, obviates intrasubject variability, and saves both analytical and animal resources.
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Bases de dados:
MEDLINE
Assunto principal:
Timolol
/
Antagonistas Adrenérgicos beta
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Chromatogr Sci
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Estados Unidos