Search results for "propranolol"
showing 10 items of 80 documents
Supernormal conduction in the right bundle branch: lack of influence of autonomic blockade.
1984
A programmed atrial stimulation at a driving rate of 100/min was performed in a 47-year-old woman with left bundle branch block. Supernormal conduction lasting 40 ms was revealed within the right bundle branch. After autonomic blockade (0.2 mg propranolol/kg body weight and 0.04 mg atropine/kg body weight) the position and duration of the supernormal conduction did not change. This suggests that the autonomic nervous system has no influence on the supernormal phase of conduction in the human intraventricular conduction system.
Beta-blockers: Historical Perspective and Mechanisms of Action
2019
Beta-blockers are widely used molecules that are able to antagonize β-adrenergic receptors (ARs), which belong to the G protein-coupled receptor family and receive their stimulus from endogenous catecholamines. Upon β-AR stimulation, numerous intracellular cascades are activated, ultimately leading to cardiac contraction or vascular dilation, depending on the relevant subtype and their location. Three subtypes have been described that are differentially expressed in the body (β1-, β2- and β3-ARs), β1 being the most abundant subtype in the heart. Since their discovery, β-ARs have become an important target to fight cardiovascular disease. In fact, since their discovery by James Black in the …
Thermodynamic analysis of binding between drugs and glycosaminoglycans by isothermal titration calorimetry and fluorescence spectroscopy
2007
The thermodynamics of the interaction of positively charged drug molecules with negatively charged glycosaminoglycans (GAGs) is investigated by isothermal titration calorimetry (ITC) and fluorescence spectroscopy. The drugs considered are propranolol hydrochloride, tacrine, and aminacrine, and the polymers used as model GAGs are dextran sulfate, chondroitin sulfate, and hyaluronic acid. The ITC results show that the interaction between drugs and GAGs is via direct binding and that GAGs bind to drugs at one set of sites. Large negative values of heat capacity change (DeltaC(p)) are observed upon binding of GAGs to drugs. Such negative DeltaC(p) is not expected for purely electrostatic intera…
Fast enantiomeric separation of propranolol by affinity capillary electrophoresis using human serum albumin as chiral selector: application to qualit…
2004
Abstract In the last years, capillary electrophoresis (CE) has gained considerable interest in pharmaceutical laboratories for controlling the chiral purity of drugs. This paper describes a simple and fast method for resolution of propranolol enantiomers by affinity capillary electrophoresis (ACE) using human serum albumin (HSA) as chiral selector. The effect of several experimental variables such as HSA concentration, temperature, chiral selector plug length and addition of organic modifiers, on the separation is evaluated. Complete enantioresolution of R- and S-propranolol was achieved in less than 5 min when the capillary was completely filled with 100 μM HSA solution and the electrophor…
Spectrophotometric Determination of Hydralazine with 2-Hydroxy-1-naphthaldehyde in Pharmaceuticals
1991
Abstract A new extraction-spectrophotometric method for the determination of hydralazine, based on its reaction with 2-hydroxy-1-naphthaldehyde at 25 °C, is described. The calibration curve was linear between 0.4 and 6 mg/mL of hydralazine. The molar absorbtivity of the product at 408 nm is 40 900 L · mol − 1 · cm − 1 . The method described was applied to the analysis of hydralazine in pharmaceutical preparations containing reserpine, hydrochlorothiazide, bendrofluorthiazine, propranolol, and other substances. The agreement with the U.S.P. XXI method was satisfactory for tablets and injections, but not for pellets.
The lack of the effect of DA-1 and DA-2 dopamine agonists on the isolated guinea-pig atria.
1987
1 The effects of dopamine and both DA-1 and DA-2 dopamine receptor agonists have been studied on the contractile force of electrically driven guinea-pig left atria and frequency of spontaneously beating right atria. 2 Pretreatment of animals with reserpine caused a parallel rightward shift of the concentration-response curve to dopamine of either preparation. 3 Propranolol, but not domperidone, shifted to the right the dose-response curve for the positive inotropic and chronotropic effects of dopamine. 4 Neither apomorphine, fenoldopam, bromocriptine nor piribedil had effects on the frequency and contractile force of the isolated guinea-pig atria. 5 These results suggest that DA-1 and DA-2 …
Comparison of Dialysis and Dispersion Methods for In Vitro Release Determination of Drugs from Multilamellar Liposomes
2008
The aim of these studies was to compare dialysis and dispersion methods for determining in vitro release of propranolol, metoprolol, pindolol, and atenolol from multilamellar liposomes. Multilamellar vesicles (MLV) were prepared using hydrogenated soy-lecithin phospholipon 90H (Ph 90H) as the primary lipid. The same volume of pH 7.4 phosphate buffered saline was used as a receptor medium for both methods. Samples were withdrawn, and drug concentration was determined using HPLC. All drug-containing liposomes exhibited an initial burst release followed by a slower rate of release. The rate and extent of drug release from MLV was dependent on the physicochemical properties of the drug. For all…
Influence of Chemical Enhancers and Iontophoresis on the In Vitro Transdermal Permeation of Propranolol: Evaluation by Dermatopharmacokinetics
2018
[EN] The aims of this study were to assess, in vitro, the possibility of administering propranolol transdermally and to evaluate the usefulness of the dermatopharmacokinetic (DPK) method in assessing the transport of drugs through stratum corneum, using propranolol as a model compound. Four chemical enhancers (decenoic and oleic acid, laurocapram, and R-(+)-limonene) and iontophoresis at two current densities, 0.25 and 0.5 mA/cm(2) were tested. R-(+)-limonene, and iontophoresis at 0.5 mA/cm(2) were proven to be the most efficient in increasing propranolol transdermal flux, both doubled the original propranolol transdermal flux. Iontophoresis was demonstrated to be superior than the chemical…
Presystemic metabolism and intestinal absorption of antipsoriatic fumaric acid esters.
2003
Psoriasis is a chronic inflammatory skin disease. Its treatment is based on the inhibition of proliferation of epidermal cells and interference in the inflammatory process. A new systemic antipsoriasis drug, which consists of dimethylfumarate and ethylhydrogenfumarate in the form of their calcium, magnesium and zinc salts has been introduced in Europe with successful results. In the present study, a homologous series of mono- and diesters of fumaric acid has been studied with respect to the sites and kinetics of presystemic ester degradation using pancreas extract, intestinal perfusate, intestinal homogenate and liver S9 fraction. In addition, intestinal permeability has been determined usi…
The Odd Sibling: Features ofβ3-Adrenoceptor Pharmacology
2014
beta(3)-Adrenoceptor agonists have recently been introduced for the treatment of overactive urinary bladder syndrome. Their target, the beta(3)-adrenoceptor, was discovered much later than beta(1)- and beta(2)-adrenoceptors and exhibits unique properties which make extrapolation of findings from the other two subtypes difficult and the beta(3)-adrenoceptor a less-understood subtype. This article discusses three aspects of beta(3)-adrenoceptor pharmacology. First, the ligand-recognition profile of beta(3)-adrenoceptors differs considerably from that of the other two subtypes, i.e., many antagonists considered as nonselective actually are beta(3)-sparing, including propranolol or nadolol. Man…