Search results for "Metoprolol"
showing 10 items of 19 documents
Viscosity-mediated negative food effect on oral absorption of poorly-permeable drugs with an absorption window in the proximal intestine: In vitro ex…
2014
Concomitant food intake can diminish oral absorption of drugs with limited permeability and an absorption window in the proximal intestine, due to viscosity-mediated decrease in dosage form disintegration time and drug dissolution rate. Three poorly-permeable drugs (atenolol, metformin hydrochloride, and furosemide) exhibiting negative food effect, and one highly-soluble and highly-permeable (metoprolol tartrate), serving as a negative control, were selected for the study. In vitro and in silico tools were used to evaluate the influence of media viscosity on drug bioperformance under fasted and fed conditions. The obtained results demonstrated that increased medium viscosity in the presence…
Micellar Liquid Chromatography: A Worthy Technique for the Determination of β-Antagonists in Urine Samples
1998
Several beta-antagonists (acebutolol, atenolol, celiprolol, labetalol, metoprolol, nadolol, propranolol) were determined in urine samples with fluorometric detection after direct injection, in less than 15 min, with a micellar mobile phase of 0.1 M sodium dodecyl sulfate (SDS), 15% propanol, and 1% triethylamine at pH 3. The limits of detection (38 criterion) were usually between 3 and 30 ng/mL. The addition of propanol and triethylamine and the reduction of the pH of the mobile phase improved the efficiency of the chromatographic peaks that was rather low in pure micellar eluents. The selection of the composition of the mobile phase was easily performed through the use of an interpretive p…
MIC trial: metoprolol in patients with mild to moderate heart failure: effects on ventricular function and cardiopulmonary exercise testing
2000
Beta-blocker therapy results in a functional benefit in patients with heart failure (CHF) due to idiopathic dilated cardiomyopathy (DCM). This study assessed if similar effects were observed in patients with ischemic heart disease (CAD), NYHA II–III after 6 months of therapy with metoprolol. Methods and results: Fifty-two patients with CHF secondary to DCM (26 patients) and CAD (26 patients) and a left ventricular ejection fraction (EF) < 40% were enrolled in the placebo-controlled study. The study medication was titrated over 6 weeks, the mean final dosage was 135 mg/day. Three patients died due to cardiogenic shock, two received placebo and one metoprolol. Eight patients did not complete …
Ability of short-time Fourier transform method to detect transient changes in vagal effects on hearts: a pharmacological blocking study.
2006
Conventional spectral analyses of heart rate variability (HRV) have been limited to stationary signals and have not allowed the obtainment of information during transient autonomic cardiac responses. In the present study, we evaluated the ability of the short-time Fourier transform (STFT) method to detect transient changes in vagal effects on the heart. We derived high-frequency power (HFP, 0.20–0.40 Hz) as a function of time during active orthostatic task (AOT) from the sitting to standing posture before and after selective vagal (atropine sulfate 0.04 mg/kg) and sympathetic (metoprolol 0.20 mg/kg) blockades. The HFP minimum point during the first 30 s after standing up was calculated and…
Increased exercise ejection fraction and reversed remodeling after long-term treatment with metoprolol in congestive heart failure: a randomized, str…
2003
Background: the effects of long-term administration of β-blockers on left ventricular (LV) function during exercise in patients with ischemic heart disease (IHD) and idiopathic dilated cardiomyopathy (DCM) are controversial. Patients and methods: patients with stable congestive heart failure (CHF) (New York heart association [NYHA] class II and III) and ejection fraction (EF) ≤0.40 were randomized to metoprolol, 50 mg t.i.d. or placebo for 6 months. Patients were divided into two groups: ischemic heart disease (IHD) and idiopathic dilated cardiomyopathy (DCM). The mean EF was 0.29 in both groups and 92% were taking angiotensin-converting enzyme (ACE) inhibitors. In the IHD group, 84% had su…
Drug gastrointestinal absorption in rat: Strain and gender differences.
2015
Predictive animal models of intestinal drug absorption are essential tools in drug development to identify compounds with promising biopharmaceutical properties. In situ perfusion absorption studies are routinely used in the preclinical setting to screen drug candidates. The objective of this work is to explore the differences in magnitude and variability on intestinal absorption associated with rat strain and gender. Metoprolol and Verapamil absorption rate coefficients were determined using the in situ closed loop perfusion model in four strains of rats and in both genders. Strains used were Sprague-Dawley, Wistar-Han, Wistar-Unilever, Long-Evans and CD∗IGS. In the case of Metoprolol only…
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…
Interpretation of Ocular Melanin Drug Binding Assays. Alternatives to the Model of Multiple Classes of Independent Sites
2016
Melanin has a high binding affinity for a wide range of drugs. The determination of the melanin binding capacity and its binding affinity are important, e.g., in the determination of the ocular drug distribution, the prediction of drug effects in the eye, and the trans-scleral drug delivery. The binding parameters estimated from a given data set vary significantly when using different isotherms or different nonlinear fitting methods. In this work, the commonly used bi-Langmuir isotherm, which assumes two classes of independent sites, is confronted with the Sips isotherm. Direct, log-log, and Scatchard plots are used, and the interpretation of the binding curves in the latter is critically a…
MiR-133 Modulates the β1Adrenergic Receptor Transduction Cascade.
2014
Rationale : The sympathetic nervous system plays a fundamental role in the regulation of myocardial function. During chronic pressure overload, overactivation of the sympathetic nervous system induces the release of catecholamines, which activate β-adrenergic receptors in cardiomyocytes and lead to increased heart rate and cardiac contractility. However, chronic stimulation of β-adrenergic receptors leads to impaired cardiac function, and β-blockers are widely used as therapeutic agents for the treatment of cardiac disease. MicroRNA-133 (miR-133) is highly expressed in the myocardium and is involved in controlling cardiac function through regulation of messenger RNA translation/stability. …
Insufficient control of heart rate in stable coronary artery disease patients in Latvia
2014
Background and objective:\ud Heart rate (HR) ≥70 beats per minute (bpm) increases cardiovascular risk in coronary artery disease (CAD) patients. The objective of the analysis is to characterize HR as well as other clinical parameters in outpatients with stable CAD in Latvia.<p></p>\ud \ud Materials and methods:\ud CLARIFY is an ongoing international registry of outpatients with established CAD. Latvian data regarding 120 patients enrolled in CLARIFY and collected at baseline visit during 2009–2010 were analyzed.<p></p>\ud \ud Results:\ud The mean HR was 67.7 ± 9.5 and 66.9 ± 10.7 bpm when measured by pulse palpation and electrocardiography, respectively. HR …