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Journal of Chromatography. A Dec 2020The capability of liquid chromatography with microemulsions (MEs) as mobile phases was studied for the analysis of four parabens (butylparaben, ethylparaben,...
The capability of liquid chromatography with microemulsions (MEs) as mobile phases was studied for the analysis of four parabens (butylparaben, ethylparaben, methylparaben, and propylparaben) and seven β-adrenoceptor antagonists (acebutolol, atenolol, carteolol, metoprolol, oxprenolol, propranolol, and timolol). MEs were formed by mixing aqueous solutions of the anionic surfactant sodium dodecyl sulphate, the alcohol 1-butanol that played the role of co-surfactant, and octane as oil. In order to guarantee the formation of stable MEs, a preliminary study was carried out to determine the appropriate ranges of concentrations of the three components. For this purpose, mixtures of variable composition were prepared, and the possible separation of two phases (formation of an emulsion) was visually detected. The advantage offered by the addition of octane to micellar mobile phases, inside the concentration range that allows the formation of stable MEs, was evaluated by comparing the retention behaviour, peak profile and resolution of mixtures of the probe compounds, in the presence and absence of octane. The final aim of this work was the proposal of a mathematical equation to model the retention behaviour in microemulsion liquid chromatography. The derived global model that considered the three factors (surfactant, alcohol and oil) allowed the prediction of retention times at diverse mobile phase compositions with satisfactory accuracy (in the 1.1‒2.5% range). The behaviour was compared with that found with mobile phases without octane. The model also yielded information about the retention mechanism and revealed that octane, when inserted inside the micelle, modifies the interaction between solutes and micelles.
Topics: Butanols; Chromatography, Liquid; Emulsions; Micelles; Models, Chemical; Parabens; Sodium Dodecyl Sulfate; Surface-Active Agents; Water
PubMed: 33166895
DOI: 10.1016/j.chroma.2020.461651 -
Analytical Methods : Advancing Methods... Jun 2020This study proposes a new multi-residue enantioselective method for the determination of emerging drug contaminants in sea water by solid phase extraction (SPE) and...
This study proposes a new multi-residue enantioselective method for the determination of emerging drug contaminants in sea water by solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). To achieve satisfactory enantiomeric separation with a vancomycin stationary phase it was essential to limit sodium chloride in extracted samples to <1 μg per injection. This was achieved through a straightforward SPE method using a 50 mL water wash volume and analyte elution in acetonitrile. A Chiral-V enantioselective column (150 × 2.1 mm; 2.7 μm particle size) operated in polar ionic mode enabled simultaneous drug separations in 30 minutes. Analytes with enantioresolution ≥1 were the stimulants amphetamine and methamphetamine, the beta-agonist salbutamol, the beta-blockers propranolol, sotalol and acebutolol, the anti-depressants fluoxetine, venlafaxine, desmethylvenlafaxine and citalopram, and the antihistamine chlorpheniramine. Method quantitation limits were <10 ng L-1 and method trueness was 80-110% for most analytes. The method was applied to samples from the Forth and Clyde estuaries, Scotland. Chiral drugs were present at concentrations in the range 4-159 ng L-1 and several were in non-racemic form (enantiomeric fraction ≠ 0.50) demonstrating enantiomer enrichment. This emphasises the need for further enantiospecific drug exposure and effect studies in the marine environment.
Topics: Chromatography, Liquid; Pharmaceutical Preparations; Scotland; Seawater; Solid Phase Extraction; Stereoisomerism; Tandem Mass Spectrometry; Water Pollutants, Chemical
PubMed: 32930212
DOI: 10.1039/d0ay00801j -
The Cochrane Database of Systematic... Sep 2020Beta-blockers are commonly used in the treatment of hypertension. We do not know whether the blood pressure (BP) lowering efficacy of beta-blockers varies across the... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Beta-blockers are commonly used in the treatment of hypertension. We do not know whether the blood pressure (BP) lowering efficacy of beta-blockers varies across the day. This review focuses on the subclass of beta-blockers with partial agonist activity (BBPAA).
OBJECTIVES
To assess the degree of variation in hourly BP lowering efficacy of BBPAA over a 24-hour period in adults with essential hypertension.
SEARCH METHODS
The Cochrane Hypertension Information Specialist searched the following databases for relevant studies up to June 2020: the Cochrane Hypertension Specialised Register; CENTRAL; 2020, Issue 5; MEDLINE Ovid; Embase Ovid; the World Health Organization International Clinical Trials Registry Platform; and ClinicalTrials.gov. We also contacted authors of relevant papers regarding further published and unpublished work. The searches had no language restrictions.
SELECTION CRITERIA
We sought to include all randomised and non-randomised trials that assessed the hourly effect of BBPAA by ambulatory monitoring, with a minimum follow-up of three weeks.
DATA COLLECTION AND ANALYSIS
Two review authors independently selected the included trials and extracted the data. We assessed the certainty of the evidence using the GRADE approach. Outcomes included in the review were end-point hourly systolic and diastolic blood pressure (SBP and DBP) and heart rate (HR), measured using a 24-hour ambulatory BP monitoring (ABPM) device.
MAIN RESULTS
Fourteen non-randomised baseline controlled trials of BBPAA met our inclusion criteria, but only seven studies, involving 121 participants, reported hourly ambulatory BP data that could be included in the meta-analysis. Beta-blockers studied included acebutalol, pindolol and bopindolol. We judged most studies at high or unclear risk of bias for selection bias, attrition bias, and reporting bias. We judged the overall certainty of the evidence to be very low for all outcomes. We analysed and presented data by each hour post-dose. Very low-certainty evidence showed that hourly mean reduction in BP and HR visually showed an attenuation over time. Over the 24-hour period, the magnitude of SBP lowering at each hour ranged from -3.68 mmHg to -17.74 mmHg (7 studies, 121 participants), DBP lowering at each hour ranged from -2.27 mmHg to -9.34 mmHg (7 studies, 121 participants), and HR lowering at each hour ranged from -0.29 beats/min to -10.29 beats/min (4 studies, 71 participants). When comparing between three 8-hourly time intervals that correspond to day, evening, and night time hours, BBPAA was less effective at lowering BP and HR at night, than during the day and evening. However, because we judged that these outcomes were supported by very low-certainty evidence, further research is likely to have an important impact on the estimate of effect and may change the conclusion.
AUTHORS' CONCLUSIONS
There is insufficient evidence to draw general conclusions about the degree of variation in hourly BP-lowering efficacy of BBPAA over a 24-hour period, in adults with essential hypertension. Very low-certainty evidence showed that BBPAA acebutalol, pindolol, and bopindolol lowered BP more during the day and evening than at night. However, the number of studies and participants included in this review was very small, further limiting the certainty of the evidence. We need further and larger trials, with accurate recording of time of drug intake, and with reporting of standard deviation of BP and HR at each hour.
Topics: Acebutolol; Adrenergic beta-Agonists; Adrenergic beta-Antagonists; Adult; Antihypertensive Agents; Bias; Blood Pressure; Circadian Rhythm; Controlled Clinical Trials as Topic; Female; Heart Rate; Humans; Hypertension; Male; Middle Aged; Pindolol; Time Factors
PubMed: 32888198
DOI: 10.1002/14651858.CD010054.pub2 -
Nephrology, Dialysis, Transplantation :... Nov 2020β-blocker (BB) dialyzability has been proposed to limit their efficacy among hemodialysis (HD) patients. We attempted to confirm this hypothesis by comparing health...
BACKGROUND
β-blocker (BB) dialyzability has been proposed to limit their efficacy among hemodialysis (HD) patients. We attempted to confirm this hypothesis by comparing health outcomes associated with the initiation of dialyzable or nondialyzable BBs in a nationwide cohort of HD patients.
METHODS
We created a prospective cohort study of 15 699 HD patients who initiated dialyzable BBs (atenolol, acebutolol, metoprolol and bisoprolol) and 20 904 hemodialysis patients who initiated nondialyzable BBs (betaxolol, carvedilol and propranolol) between 2004 and 2011 in Taiwan healthcare. We compared the risk of all-cause mortality and major adverse cardiovascular events (MACEs, a composite of the acute coronary syndrome, ischemic stroke and heart failure) between users of dialyzable versus nondialyzable BBs during a 2-year follow-up.
RESULTS
New users of dialyzable BBs were younger, more often men, with diabetes mellitus, hypertension and hyperlipidemia compared with users of nondialyzable BBs. Compared with nondialyzable BBs, initiation of dialyzable BBs was associated with lower all-cause mortality {hazard ratio [HR] 0.82 [95% confidence interval (CI) 0.75-0.88]} and lower risk of MACEs [HR 0.89 (95% CI 0.84-0.93)]. Results were confirmed in subgroup analyses, censoring at BB discontinuation or switch, after 1:1 propensity score matching, reclassifying bisoprolol or excluding bisoprolol/carvedilol users.
CONCLUSIONS
This study does not offer support for the hypothesis that the dialyzability of BBs reduces their efficacy in HD patients.
Topics: Adrenergic beta-Antagonists; Cardiovascular Diseases; Female; Humans; Kidney Failure, Chronic; Male; Middle Aged; Prognosis; Prospective Studies; Renal Dialysis; Survival Rate; Taiwan
PubMed: 32719861
DOI: 10.1093/ndt/gfaa058 -
Journal of Chromatography. A Aug 2020The influence of impregnation the chromatographic plate adsorbent layer, silica, with hen's egg white albumin (OVA) or bovine serum albumin (BSA) on the retention of...
The influence of impregnation the chromatographic plate adsorbent layer, silica, with hen's egg white albumin (OVA) or bovine serum albumin (BSA) on the retention of some popular medicines (paracetamol, aminophenazone, theophylline, caffeine, acetanilide, ciprofloxacin, tramadol, acetylsalicylic acid, acebutolol) is investigated. The effect of composition and buffer pH of the mobile phase on solute separation selectivity is also studied. The chromatographic systems with and without above mentioned albumins and their influence on investigated drug retention are compared. In general, it has been turned out that retention of tested medicines in systems with the sorbent impregnated with albumin significantly increase relative to those with non-impregnated.
Topics: Adsorption; Animals; Cattle; Chickens; Chromatography, Thin Layer; Egg White; Female; Hydrogen-Ion Concentration; Methanol; Organic Chemicals; Pharmaceutical Preparations; Serum Albumin, Bovine; Silica Gel; Solvents; Spectroscopy, Fourier Transform Infrared; Toluene
PubMed: 32709329
DOI: 10.1016/j.chroma.2020.461277 -
Expert Review of Clinical Pharmacology Aug 2020Fifteen percent of proliferating infantile hemangioma (IH) require intervention because of the threat to function or life, ulceration, or tissue distortion. Propranolol... (Review)
Review
INTRODUCTION
Fifteen percent of proliferating infantile hemangioma (IH) require intervention because of the threat to function or life, ulceration, or tissue distortion. Propranolol is the mainstay treatment for problematic proliferating IH. Other β-blockers and angiotensin-converting enzyme (ACE) inhibitors have been explored as alternative treatments.
AREAS COVERED
The demonstration of a hemogenic endothelium origin of IH, with a neural crest phenotype and multi-lineage differentiation capacity, regulated by the renin-angiotensin system, underscores its programmed biologic behavior and accelerated involution induced by propranolol, other β-blockers and ACE inhibitors. We review the indications, dosing regimens, duration of treatment, efficacy and adverse effects of propranolol, and therapeutic alternatives including oral atenolol, acebutolol, nadolol, intralesional propranolol injections, topical propranolol and timolol, and oral captopril.
EXPERT OPINION
Improved understanding of the biology of IH provides insights into the mechanism of action underscoring its accelerated involution induced by propranolol, other β-blockers and ACE inhibitors. More research is required to understand the optimal dosing and duration, efficacy and safety of these alternative therapies. Recent demonstration of propranolol's actions mediated by non-β-adrenergic isomer R-propranolol on stem cells, offers an immense opportunity to harness the efficacy of β-blockers to induce accelerated involution of IH, while mitigating their β-adrenergic receptor-mediated adverse effects.
Topics: Adrenergic beta-Antagonists; Angiotensin-Converting Enzyme Inhibitors; Animals; Hemangioma; Humans; Infant; Propranolol; Renin-Angiotensin System; Skin Neoplasms
PubMed: 32662682
DOI: 10.1080/17512433.2020.1788938 -
Chemistry (Weinheim An Der Bergstrasse,... Sep 2020Chemical exchange saturation transfer (CEST) MRI has recently emerged as a versatile molecular imaging approach in which diamagnetic compounds can be utilized to...
Chemical exchange saturation transfer (CEST) MRI has recently emerged as a versatile molecular imaging approach in which diamagnetic compounds can be utilized to generate an MRI signal. To expand the scope of CEST MRI applications, herein, we systematically investigated the CEST properties of N-aryl amides with different N-aromatic substitution, revealing their chemical shifts (4.6-5.8 ppm) and exchange rates (up to thousands s ) are favorable to be used as CEST agents as compared to alkyl amides. As the first proof-of-concept study, we used CEST MRI to detect the enzymatic metabolism of the drug acebutolol directly by its intrinsic CEST signal without any chemical labeling. Our study implies that N-aryl amides may enable the label-free CEST MRI detection of the metabolism of many N-aryl amide-containing drugs and a variety of enzymes that act on N-aryl amides, greatly expanding the scope of CEST MR molecular imaging.
Topics: Amides; Contrast Media; Magnetic Resonance Imaging; Molecular Imaging
PubMed: 32639618
DOI: 10.1002/chem.202002415 -
Arhiv Za Higijenu Rada I Toksikologiju Mar 2020Beta-blockers are chiral compounds with enantiomers that have different bioactivity, which means that while one is active, the other can be inactive or even harmful. Due...
Beta-blockers are chiral compounds with enantiomers that have different bioactivity, which means that while one is active, the other can be inactive or even harmful. Due to their high consumption and incomplete degradation in waste water, they may reach surface waters and affect aquatic organisms. To address this issue we developed a chromatographic method suitable for determining beta-blocker enantiomers in surface waters. It was tested on five beta-blockers (acebutolol, atenolol, bisoprolol, labetalol and metoprolol) and validated on bisoprolol enantiomers. Good enantioseparation of all analysed beta-blockers was achieved on the Chirobiotic V column with the mobile phase composed of methanol/acetic acid/triethylamine (100/0.20/0.15 v/v/v) at a flow rate of 0.5 mL/min and column temperature of 45 °C. Method proved to be linear in the concentration range from 0.075 µg/mL to 5 µg/mL, and showed good recovery. The limits of bisoprolol enantiomer detection were 0.025 µg/mL and 0.026 µg/mL and of quantification 0.075 µg/mL and 0.075 µg/mL. Despite its limitations, it seems to be a promising method for bisoprolol enantiomer analysis in surface water samples. Further research could focus on waste water analysis, where enantiomer concentrations may be high. Furthermore, transferring the method to a more sensitive one such as liquid chromatography coupled with tandem mass spectrometry and using ammonium acetate as the mobile phase additive instead of acetic acid and triethylamine would perhaps yield much lower limits of detection and quantification.
Topics: Acebutolol; Adrenergic beta-Antagonists; Atenolol; Bisoprolol; Chromatography, High Pressure Liquid; Labetalol; Metoprolol; Water
PubMed: 32597137
DOI: 10.2478/aiht-2020-71-3318 -
The Medical Letter on Drugs and... May 2020
Topics: Antihypertensive Agents; Blood Pressure; Humans; Hypertension
PubMed: 32555118
DOI: No ID Found -
Environmental Pollution (Barking, Essex... Jul 2020The importance of stereochemistry on the behaviour and effects of chiral pharmaceutical and illicit drugs in amended agricultural soils has been over looked to date....
The importance of stereochemistry on the behaviour and effects of chiral pharmaceutical and illicit drugs in amended agricultural soils has been over looked to date. Therefore, this study was aimed at investigating the enantiospecific behaviour of a chemically diverse range of chiral drugs including naproxen, ibuprofen, salbutamol, bisoprolol, metoprolol, propranolol, acebutolol, atenolol, chlorpheniramine, amphetamine, fluoxetine and citalopram in soil microcosms. Considerable changes of the enantiomeric composition of ibuprofen, naproxen, atenolol, acebutolol and amphetamine were observed within 56 d. This is significant as enantiomer enrichment can favour the pharmacologically active (e.g., S(-)-atenolol) or less/non-active forms of the drug (e.g., R(-)-amphetamine). Single enantiomer microcosms showed enantiospecific degradation was responsible for enantiomer enrichment of atenolol and amphetamine. However, naproxen and ibuprofen enantiomers were subject to chiral inversion whereby one enantiomer converts to its antipode. Interestingly, chiral inversion was bidirectional and this is the first time it is reported in soil. Therefore, introduction of the less active enantiomer to soil through irrigation with reclaimed wastewater or biosolids as fertiliser can result in the formation of its active enantiomer, or vice versa. This phenomenon needs considered in risk assessment frameworks to avoid underestimating the risk posed by chiral drugs in amended soils.
Topics: Ibuprofen; Illicit Drugs; Soil; Stereoisomerism; Wastewater
PubMed: 32443211
DOI: 10.1016/j.envpol.2020.114364