Search results for "Propanolamines"
showing 10 items of 23 documents
Quantitation of talinolol in rat plasma by LC-MS-MS.
2010
The aim of this study was to develop and validate an assay based on liquid chromatography-tandem mass spectrometry to quantitate talinolol in rat plasma. After a simple protein precipitation step, separation was performed by reversed-phase liquid chromatography using gradient elution with acetonitrile-water-formic acid. Electrospray ionization in the positive ion mode with multiple reaction monitoring was used to analyze talinolol employing propranolol as internal standard. The calibration curve for talinolol was linear over the concentration range 1-250 ng/mL with a correlation coefficient0.995. The method was sensitive (limit of quantitation, 1 ng/mL) and had acceptable accuracy (85-115% …
Systematic review with meta-analysis: the haemodynamic effects of carvedilol compared with propranolol for portal hypertension in cirrhosis
2013
Summary Background Propranolol is recommended for prophylaxis of variceal bleeding in cirrhosis. Carvedilol is a nonselective beta-blocker with a mild anti-alfa-1-adrenergic activity. Several studies have compared carvedilol and propranolol, yielding inconsistent results. Aim To perform a systematic review and meta-analysis of the randomised clinical trials comparing carvedilol with propranolol for hepatic vein pressure gradient reduction. Methods Studies were searched on the MEDLINE, EMBASE and Cochrane library databases up to November 2013. The weighted mean difference in percent hepatic vein pressure gradient reduction and the relative risk of failure to achieve a hemodynamic response (r…
Origin and correction of the deviations in retention times at increasing flow rate with Chromolith columns.
2010
Chromoliths can be used at flow rates beyond those feasible for conventional microparticulate packed columns. Ideally, the plots of the retention time versus the inverse of delivered flow rate should exhibit y-intercept of zero. However, significant positive deviations correlating with the solute polarity were observed for several compounds chromatographed with a Chromolith column, owing to the increased system pressure. Consequently, the dead time marker exhibits a smaller deviation, making the retention factors depend on the flow rate. Chromoliths are made of a silica-based monolith encapsulated within a PEEK tube, and should suffer larger stress with pressure than stainless steel columns…
Effect of single-dose and short-term administration of quercetin on the pharmacokinetics of talinolol in humans – Implications for the evaluation of …
2013
Quercetin has been shown to inhibit intestinal P-glycoprotein-mediated drug efflux. A crossover clinical study was performed in 10 healthy volunteers to assess the effect of single-dose and repeated quercetin intake on the pharmacokinetics of talinolol, a substrate of intestinal P-glycoprotein. Unexpectedly, mean area under the plasma concentration-time curve (AUC0-48h) and maximal plasma concentration (cmax) were slightly decreased following concomitant and short-term quercetin administration (3186.0 versus 2468.3 and 2527.7 ng h/ml, p>0.05; 309.7 versus 212.0 and 280.6 ng/ml, p>0.05). Individual analysis revealed that talinolol AUC0-48h was lowered by 23.9% up to 60.6% in 5 subjects and c…
Pretreatment with potent P-glycoprotein ligands may increase intestinal secretion in rats.
2001
The expression of P-glycoprotein is induced in cell cultures upon exposure to various inducers. Therefore, the aim of the present study was to evaluate the in-vivo relevance of this observation, i.e. the influence of chronic pretreatments with selected drugs -- all of which are ligands to P-glycoprotein (P-gp) as demonstrated in radioligand binding studies and all of which have some or a considerable effect on P-gp expression in Caco-2 cells -- on the effective intestinal permeabilities of the model compound talinolol in rats employing in-situ single-pass intestinal perfusion of three different gut segments. Talinolol was selected, because it shows high selectivity for one of the exsorptive…
Modulation of drug transport by selected flavonoids: Involvement of P-gp and OCT?
2004
Flavonoids, as a common component of daily nutrition, are a possible source of interference with absorption processes, due to modulation of transporting proteins. In this study, the influence of selected flavonoids (quercetin, isoquercitrin, spiraeoside, rutin, kaempferol, naringenin, naringin, and kaempferol) on the transport of the P-gp substrate [3H]talinolol across Caco-2 cell monolayers was investigated. To elucidate the mechanism behind the interaction observed in this system the potency of the flavonoids to replace [3H]talinolol from its P-gp binding site as well as their activity to inhibit OCT2-mediated [14C]TEA uptake into LLC-PK(1) cells were measured, as P-gp and OCT have been s…
Pharmacokinetics of atenolol in relation to renal function
1981
The plasma levels and urinary excretion of carteolol and its main metabolites 8-hydroxycarteolol and carteolol glucuronide were investigated in 6 healthy subjects and 9 patients with varying degrees of renal impairment following a single oral dose of 30 mg carteolol hydrochloride. In healthy subjects the half-life of carteolol was 7.1 h. 63% of the administered dose was recovered unchanged in urine, and in all 84% was excreted by the kidneys. The renal clearance of carteolol was 255 ml/min. In chronic renal failure (CRF) the terminal half-life was increased to a maximum of 41 h. Both the elimination rate constant and renal clearance were closely related to the creatinine clearance. In CRF t…
Beta-adrenoceptor density and subtype distribution in cerebellum and hippocampus from patients with Alzheimer's disease
1993
beta-Adrenoceptor density and beta 1- and beta 2-subtype distribution were examined in hippocampi and cerebella from patients with Alzheimer's disease (AD/SDAT). Tissues from age-, sex and post-mortem delay matched non-demented patients served as controls. The total beta-adrenoceptor density as evaluated in saturation experiments with the hydrophilic radioligand [3H]CGP 12177 was higher in hippocampal (36-39 fmol/mg protein) than cerebellar tissues (20-21 fmol/mg), however, no differences were found in either brain region between AD/SDAT patients and controls. Subtype distribution using the highly selective beta 1-adrenoceptor antagonist CGP 20712A revealed a slightly higher proportion of b…
Clinical pharmacokinetics of atenolol — A review
1982
Atenolol is a hydrophilic betareceptor blocking drug, which is predominantly eliminated via the kidneys, only about 5% of the atenolol is metabolised by the liver. After oral administration atenolol is incompletely absorbed from the intestine, so about 50% of the beta blocker are finally biovailable. In plasma only 3% of atenolol are protein-bound. There exists a linear relationship between the atenolol plasma levels and the degree of beta blocking effect measured by inhibition of the exercise-induced tachycardia. No correlation was found between plasma levels of atenolol and blood pressure lowering activity of the drug. After oral administration elimination half life of atenolol is calcula…
Interaction of atenolol with furosemide and calcium and aluminum salts
1981
Six healthy subjects were treated with 100 mg atenolol. After a therapy-free interval of 4 wk the same subjects received the same dose of atenolol with furosemide, 40 mg, with calcium (as the lactate gluconate and carbonate), 500 mg, or with aluminum hydroxide, 5.6 gm. Atenolol alone and in combination was administered first as a single oral dose; a long-term 6-day treatment began 48 hr later. Addition of furosemide did not influence atenolol kinetics, but aluminum hydroxide led to an insignificant reduction (P greater than 0.05) of mean peak plasma levels of about 20% and of the area under the plasma concentration-time curve (AUC -infinity) from 5818 to 4353 ng ml-1 hr (P greater than 0.05…