Quantitative determination of tertatolol in biological fluids by gas chromatography-mass spectrometry

Stereoselective HPLC analysis of tertatolol in rat plasma using macrocyclic antibiotic chiral stationary phase

Enantiomeric resolution of teratolol was achieved on a vancomycin macrocyclic antibiotic chiral stationary phase known as Chirobiotic V with UV detection set at 220 nm. The polar ionic mobile phase (PIM) consisted of methanol-glacial acetic acid-triethylamine (100:0.01:0.015, v/v/v) has been used at a flow rate of 0.8 ml min(-1) . The calibration curves in plasma were linear over the range of 5-500 ng ml(-1) for each enantiomer with detection limit of 2 ng ml(-1) . The proposed method was validated in compliance with the international conference on harmonization (ICH) guidelines. The developed method applied for the trace analyses of tertatolol enantiomers in plasma and for the pharmacokinetic study of tertatolol enantiomers in rat plasma. The assay proved to be suitable for therapeutic drug monitoring and chiral quality control for tertatolol formulations by HPLC.

Hemodynamic and pharmacokinetic study of tertatolol in patients with alcoholic cirrhosis and portal hypertension

Tertatolol, a recently developed beta 1-beta 2-blocker has two advantages: it does not induce withdrawal syndrome after abrupt cessation, and it preserves renal function. It has been suggested that the kinetics of tertatolol in patients with hepatic dysfunction are altered. Therefore, the hemodynamic effects and pharmacokinetics following the acute administration of tertatolol were studied in cirrhotic patients with portal hypertension. Systemic, splanchnic and renal hemodynamics were evaluated before and 30 min after the simultaneous administration of 2.5 mg tertatolol p.o. and 1.25 mg deuterated tertatolol i.v. in 10 cirrhotic patients with esophageal varices. The pharmacokinetics of tertatolol were evaluated over a 4-day period. Tertatolol significantly decreased heart rate (-22 +/- 10%), cardiac output (-26 +/- 8%), and hepatic blood flow (-27 +/- 23%). The hepatic venous pressure gradient decreased from 15.7 +/- 5.0 to 12.9 +/- 4.0 mmHg (-17 +/- 13%, P < 0.01). Three out of 10 patients were non-responders to tertatolol. Renal blood flow (-9 +/- 28%) and intrinsic hepatic clearance of indocyanin green (-9 +/- 25%) were not significantly modified. The duration of effective beta-blockade was far less than 12 h. Tertatolol was rapidly absorbed with a Cmax of 70 +/- 51 micrograms/l at a peak time of 0.75 +/- 0.26 h. In comparison with healthy volunteers referred to in literature sources, plasma clearance was reduced to 49 +/- 28 ml/min, bioavailability was increased to 72 +/- 20%, and the volume of distribution was increased to 50 +/- 34 l, probably due, in part, to a weaker protein binding -85%--effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of tertatolol enantiomers in biological fluids by high-performance liquid chromatography

A stereospecific high-performance liquid chromatographic method for the quantification of (-)- and (+)-tertatolol in plasma and urine is described. The method involves solid-phase extraction followed by derivatization with S(+)-naphthylethylisocyanate to form the urea derivative, which is more sensitive to fluorescence detection. The separation of the diastereomeric derivatives was performed by reversed-phase high-performance liquid chromatography. Fluorimetric detection (lambda excitation = 220 nm, lambda emission = 320 nm) allows the quantification of tertatolol enantiomers down to 6 ng/ml. The assay was used to study the pharmacokinetic profile of tertatolol enantiomers following oral administration of racemic tertatolol; preliminary results suggest enantioselective absorption and/or disposition of tertatolol.

Chromatography of beta-adrenergic blocking agents

The determination of beta-blockers has posed pharmaceutical analysts with a variety of problems arising from the essential characteristics of these compounds as bases and the variability of physicochemical properties of individual drugs. Liquid chromatography has become the favoured method of analysis and to a certain extent there is a standardised approach to analysis based on either solvent or solid-phase extraction and reversed-phase high-performance liquid chromatography coupled to fluorescence detection. The analyst must be aware of interactions occurring during extraction stages. All manipulations should be fully evaluated for individual drugs and metabolites prior to use. Other analytical options are chosen for specific or more demanding applications. The use of unmodified silicas for the liquid chromatography of beta-blockers (and other basic drugs) is an example of a potential alternative mode of chromatography. The stereoselectivity of the pharmacology of beta-blockers has spawned a great deal of literature describing the resolution of enantiomers by chromatographic methods. It is envisaged that this area will achieve greater prominence in the future as drug development pursues optical purity. The demand for the availability of enantiomerically pure pharmaceutical preparations will certainly see developments for preparative-scale separations as well as analytical methods and will surely promote developments in new and established methods of chromatography.

Interaction of tertatolol with rifampicin and ranitidine pharmacokinetics and antihypertensive activity

The interaction of the new beta-receptor antagonist tertatolol with rifampicin and ranitidine was investigated in ten patients with arterial hypertension (WHO stages I-II). They were treated orally with a single dose of tertatolol 5 mg alone and, after randomized allocation, with ranitidine 150 mg twice daily or rifampicin 600 mg once daily for 1 week each (tertatolol 5 mg was concurrently administered on the seventh day of the treatment phases). Following each therapeutic phase, circadian blood pressure values as well as kinetic parameters were obtained. On treatment with tertatolol alone, maximum plasma concentrations were 123.7 +/- 32.4 ng/ml (mean +/- SD) and were reached after 1.95 +/- 1.77 hours. The tertatolol elimination half-life was 9.0 +/- 7.1 hours. Coadministration of ranitidine did not significantly alter the kinetic parameters and antihypertensive effect of tertatolol. Rifampicin, however, decreased the maximum plasma levels of tertatolol to 80.6 +/- 18.5 ng/ml and markedly shortened the elimination half-life to 3.4 +/- 2.6 hours (p less than 0.01 compared with tertatolol alone). Urinary excretion of parent tertatolol and unchanged 4-hydroxy tertatolol was decreased under rifampicin, and a tendency to a reduction in the effect of tertatolol on circadian blood pressure values was observed. Twenty-four hours after administration, the heart rate in those patients on tertatolol alone (68 +/- 6 beats/min) was lower than in those on tertatolol plus rifampicin (74 +/- 7 beats/min). In conclusion, a pronounced pharmacokinetic interaction, with a limited consequence in terms of pharmacodynamic effects, was found in the present study when tertatolol was administered with rifampicin, but not with ranitidine.

Preserved renal perfusion during beta blockade by tertatolol with and without cyclooxygenase inhibition in normal humans

The systemic and renal hemodynamic effects of tertatolol, a new noncardioselective beta blocker without partial agonist activity, given alone or in combination with cyclooxygenase inhibition by acetylsalicylic acid (aspirin), were investigated in eight healthy volunteers. Tertatolol 5 mg, aspirin 1 g, tertatolol 5 mg together with aspirin 1 g and placebo were administered at 1-week intervals in a random order and in a double-blind fashion. Cardiac output was measured by Doppler echography and renal blood flow and glomerular filtration rate (GFR) by constant infusion techniques using (123I) iodohippurate and (51Cr) EDTA, respectively. Measurements were performed before and then successively 2 and 4 hours after oral intake of drugs or placebo. Tertatolol decreased cardiac output by 22% (P less than .05) and heart rate by 17% (P less than .05) without change in blood pressure, renal blood flow, and GFR. The same effects occurred when tertatolol was given together with aspirin. Either placebo or aspirin alone had no effect on systemic and renal hemodynamics. These results suggest that cardiac output is redistributed to the kidneys after tertatolol intake in normal humans. This favorable effect on renal hemodynamics is probably not mediated by a local release of vasodilating prostaglandins.

Prolonged beta blockade due to tertatolol: a comparative study with propranolol and atenolol

Submaximal exercise heart rate was measured after oral administration of placebo, tertatolol 5 mg, propranolol 80 mg, and atenolol 100 mg to 12 subjects in a double-blind cross-over study. The peaks of beta-blocking activity, observed at 2 hr, were of similar extent for the 3 drugs. The duration of activity of tertatolol, a beta blocker with a short elimination half-life, extended up to 24 hr as did that of atenolol, but was longer than that of propranolol which reached only 18 hr. These results support once-daily administration of tertatolol in therapy.

Capillary gas chromatographic-mass spectrometric study of the effect of solvents on metoprolol and other aryloxypropanolamines

When metoprolol in methanol was analysed by capillary gas chromatography (GC), an additional peak was observed; mass spectrometry (MS) showed this additional peak to have a molecular weight 12 dalton higher than that of the parent compound. A similar phenomenon was observed with other beta-adrenergic blocking aryloxypropanolamines in methanol or dichloromethane. Capillary GC-MS using deuterated solvents as isotopic markers showed that a methylene group from the solvents was incorporated into the parent molecule. The structure of the observed products and the mechanism of their formation are proposed.

Airway response to salbutamol and to ipratropium bromide after non-selective and cardioselective beta-blocker

Eight healthy men were randomly assigned in a latin square order to receive single doses of placebo, tertatolol 5 mg, propranolol 80 mg and atenolol 100 mg at 7-day intervals. Resting heart rate and pulmonary function were measured 10 min before and over the 240 min following dosing, and then 15 min after inhalation of salbutamol 200 micrograms and ipratropium bromide 40 micrograms. The three beta-blockers caused similar reductions in resting heart rate throughout the study, whereas placebo had no effect. The three beta-blockers, like placebo, produced no significant change in pulmonary function during the 240 min after dosing. The bronchodilator response to salbutamol after atenolol and placebo was preserved, whereas it was reduced after administration of either of the non-selective beta-blockers, tertatolol and propranolol. An unequivocal response of the airways to ipratropium bromide was observed after tertatolol and propranolol, which was much greater than after atenolol. No response was observed after placebo. Thus, despite bronchial beta 2-blockade, by non-selective beta-blockers, bronchodilatation was definitely produced by ipratropium bromide, confirming the predominant role of the parasympathetic system in the autonomic innervation of normal human airways.