Simultaneous determination of propranolol and 4-hydroxy propranolol in human plasma by solid phase extraction and liquid chromatography/electrospray tandem mass spectrometry

Complete Reaction Phenotyping of Propranolol and 4-Hydroxypropranolol with the 19 Enzymes of the Human UGT1 and UGT2 Families

Propranolol is a competitive non-selective beta-receptor antagonist that is available on the market as a racemic mixture. In the present study, glucuronidation of propranolol and its equipotent phase I metabolite 4-hydroxypropranolol by all 19 members of the human UGT1 and UGT2 families was monitored. UGT1A7, UGT1A9, UGT1A10 and UGT2A1 were found to glucuronidate propranolol, with UGT1A7, UGT1A9 and UGT2A1 mainly acting on (S)-propranolol, while UGT1A10 displays the opposite stereoselectivity. UGT1A7, UGT1A9 and UGT2A1 were also found to glucuronidate 4-hydroxypropranolol. In contrast to propranolol, 4-hydroxypropranolol was found to be glucuronidated by UGT1A8 but not by UGT1A10. Additional biotransformations with 4-methoxypropanolol demonstrated different regioselectivities of these UGTs with respect to the aliphatic and aromatic hydroxy groups of the substrate. Modeling and molecular docking studies were performed to explain the stereoselective glucuronidation of the substrates under study.

A Novel Voltametric Measurements of Beta Blocker Drug Propranolol on Glassy Carbon Electrode Modified with Carbon Black Nanoparticles

A new voltametric method for highly sensitive propranolol (PROP) determination was developed. A glassy carbon electrode modified with a hybrid material made of carbon black (CB) and Nafion was used as the working electrode. The preconcentration potential and time were optimized (550 mV and 15 s), as well as the supporting electrolyte (0.1 mol L⁻¹ H₂SO₄). For 15 s preconcentration time, linearity was achieved in the range 0.5–3.5 μmol L⁻¹ and for 120 s in 0.02–0.14 μmol L⁻¹. Based on the conducted calibration (120 s preconcentration time) limit of detection (LOD) was calculated and was equal to 7 nmol L⁻¹. To verify the usefulness of the developed method, propranolol determination was carried out in real samples (tablets and freeze-dried urine). Recoveries were calculated and were in the range 92–102%, suggesting that the method might be considered as accurate. The repeatability of the signal expressed as relative standard deviation (RSD) was equal to 1.5% (n = 9, PROP concentration 2.5 µmol L⁻¹). The obtained results proved that the developed method for propranolol determination might be successfully applied in routine laboratory practice.

Graphene and zeolite as adsorbents in bar-micro-solid phase extraction of pharmaceutical compounds of diverse polarities

A bar micro-solid phase (bar μ-SPE) extraction method using either graphene or zeolite or their mixtures as an adsorbent, coupled with high-performance liquid chromatography (using a C1 column) was developed for the simultaneous determination of pharmaceutical compounds (metformin (MET), buformin (BUF), phenformin (PHEN) and propranolol (PROP)) of diverse polarity (log P from −1.82 to 3.10). Parameters influencing the extraction, such as conditioning solvents, pH of the sample, sample volume, amount of adsorbent, stirring rate, time of extraction, type and volume of desorption solvent and time of desorption were investigated. Under the optimized conditions, the extraction method using graphene (extraction efficiency, % EE, ∼6–15%) resulted in the least amount of extracted drugs. However, the use of zeolite and zeolite/graphene mixtures improves the % EE significantly, i.e. 30% for PHEN and 42% for PROP using zeolite; 22% for MET and 18% for BUF using the adsorbent mixture. Under similar conditions, enrichment factors for these drugs range from 11–15. The validated method was performed for the determination of the drugs that were spiked to urine samples. Good recoveries ranging from 72.8 to 116% were achieved.

A bar micro-solid phase (bar μ-SPE) extraction method using either graphene or zeolite or their mixtures as an adsorbent, coupled with high-performance liquid chromatography was developed for the determination of pharmaceutical compounds of diverse polarity.

A new electrochemical sensing platform based on HgS/graphene composite deposited on the glassy carbon electrode for selective and sensitive determination of propranolol

Fabrication of selective, sensitive and reliable sensing platform for detection of propranolol (PRO) is still a great challenge. In this study, a new sensitive and selective electrochemical sensor was fabricated for the electrochemical determination of PRO using HgS/graphene composite. The incorporation of HgS microstructures on graphene sheets was done via a facile one-step method, where the simultaneous reduction of GO and the in-situ generation of HgS happened. Owing to the large surface area, excellent electronic conductivity and more electro-active sites provided by graphene, the HgS/graphene composite exhibited better electrochemical ability through the detection of PRO compared to the bare HgS. The HgS/graphene sensor revealed superb selectivity, good repeatability and superior stability of about 96.0 % of its original response after five weeks. Moreover, the sensor displayed excellent analytical parameters such as linear range of 0.5-50.0 μM with low detection limit of 0.05 μM (S/N = 3) and good sensitivity (0.1851 μA/μM). Furthermore, the constructed sensor was applied for detection of PRO in real and pharmaceutical samples, with good recoveries, ranging from 96.0 to 102.0%. The HgS/graphene composite provided here displayed satisfactory electrochemical features may hold great potential to the improvement of electrochemical sensors and electronic devices.

In vitro biotransformation of pharmaceuticals and pesticides by trout liver S9 in the presence and absence of carbamazepine

The aim of the present study was to develop (i) a technique for identifying metabolites of organic contaminants by using an in vitro system of trout S9 and liquid chromatography-high-resolution mass spectrometry-based identification method and (ii) to apply this technique to identify the interactive potential of carbamazepine on the formation rate of other metabolites. The pharmaceuticals carbamazepine and propranolol and the pesticides azoxystrobin, diazinon, and fipronil were selected as test contaminants. As a result, a total of ten metabolites were identified for the five parent substances, six of which were confirmed using reference standards. Metabolic reactions included hydroxylation, epoxidation, S-oxidation, and dealkylation. The metabolic transformation rate ranged from 0.2 to 3.5 pmol/mg protein/min/μmol substrate. In the binary exposure experiment with increasing carbamazepine concentration, the formation rates of diazinon and fipronil metabolites (MDI2 and MFP2, respectively) increased, while formation of metabolites of propranolol and azoxystrobin (MPR1, MPR2, MPR3, and MAZ1) slowed down. Meanwhile, S9 pre-exposed to carbamazepine produced diazoxon, a toxic metabolite of diazinon, and pyrimidinol, a less toxic metabolite, more rapidly. These results suggest that carbamazepine, a perennial environmental pollutant, might modulate the toxicity of other substances such as diazinon but further in vivo studies are needed.

Distribution and fate of pharmaceuticals and their metabolite conjugates in a municipal wastewater treatment plant

Some pharmaceutical conjugates can be excreted into wastewaters at levels rivalling those of the parent compounds; however, little is known about this potential reservoir of pharmaceuticals to aquatic systems. We evaluated the occurrence and distribution of four different classes of pharmaceuticals and their metabolite conjugates in a wastewater treatment plant over four months. Aqueous and suspended solids fractions of primary, mixed liquor, secondary, and final effluent, along with return activated sludge, and waste activated sludge were assessed. The only conjugate not found in the final effluent was acetaminophen sulfate. Moreover, thyroxine and thyroxine glucuronide were the only compounds quantified in the suspended solids in the final effluent. Propranolol, propranolol sulfate, thyroxine, and thyroxine glucuronide all had no significant decreases in concentration going through the wastewater treatment process, from primary to final effluent. However, there were significant decreases observed for acetaminophen (99.8%), sulfamethoxazole (71%), N-acetyl sulfamethoxazole (59%), and sulfamethoxazole glucuronide (79%). The mean (±SEM) mass loadings in the aqueous fraction of the final effluent for each compound ranged from 0.84 ± 0.2 g/d for thyroxine to 45.3 ± 4.2 g/d for acetaminophen. At least as much conjugate was released into receiving waters, if not more: 1.6 ± 0.2 g/d for thyroxine glucuronide to 18.5 ± 4.5 g/d for sulfamethoxazole glucuronide, and 61.2 ± 9.6 g/d for N-acetyl sulfamethoxazole. Additionally, the mean loading of thyroxine was 0.29 ± 0.025 g/day and thyroxine glucuronide 1.8 ± 0.59 g/day in the suspended solids. This equates to 26% of total thyroxine and 53% of total thyroxine glucuronide associated with suspended particulate matter that reaches receiving waters. This study reflects the importance of including phase II conjugates in assessing overall compound load of pharmaceutical discharge from wastewaters, and also that substantial amounts of such contaminants are associated with wastewater solids when drugs are in the pg/L to μg/L range.

An improved HPLC-MS/MS method for simultaneous quantification of propranolol and its two phase I metabolites in plasma of infants with hemangioma and its application to a comparative study of plasma concentrations

Propranolol is now a preferred treatment for infantile hemangioma. However, there are no published papers on the metabolism and concentrations of propranolol in the plasma of infants with hemangioma. In the present study, a sensitive, simple and reliable method was developed and validated for the simultaneous quantification of propranolol and its metabolites 4-hydroxypropranolol (M1) and N-desisopropylpropranolol (M2) in infants' plasma for the first time by using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A volume of 100 μL plasma was prepared by one-step protein precipitation with acetonitrile (300 μL), followed by its separation on an Hypersil GOLD C₁₈ column maintained at 40 °C with gradient mobile phase consisting of 0.1% formic acid aqueous solution and acetonitrile at a flow rate of 0.3 mL min⁻¹. The quantification was performed via multiple reaction monitoring (MRM) by a triple quadrupole mass spectrometer under positive electrospray ionization (ESI) mode. Bisoprolol was chosen as the internal standard. The method was validated to demonstrate its selectivity, linearity, accuracy, precision, recovery, matrix effect and stability. The matrix-matched calibration curves for propranolol ranging from 1 to 500 ng mL⁻¹, for M1 ranging from 0.2 to 100 ng mL⁻¹ and for M2 ranging from 0.2 to 100 ng mL⁻¹ were all linear, with correlation coefficients calculated using weighted (1/x²) least square linear regression analysis. The lower limits of quantification (LLOQs) were 1 ng mL⁻¹, 0.2 ng mL⁻¹ and 0.2 ng mL⁻¹ for propranolol, M1 and M2, respectively. The intra-day and inter-day precisions were less than 7.1% and relative errors were all less than 9.8%. This validated method was successfully applied to quantify the concentrations of propranolol and its metabolites 4-hydroxypropranolol (M1) and N-desisopropylpropranolol (M2) in the plasma of infants with hemangioma after oral administration of different doses of propranolol for the first time.

Comparative study of propranolol, 4-hydroxypropranolol and N-desisopropylpropranolol in the plasma of infants with hemangioma after oral administration of different doses of propranolol.

HPLC column-switching technique for sample preparation and fluorescence determination of propranolol in urine using fused-core columns in both dimensions

A new and fast high-performance liquid chromatography (HPLC) column-switching method using fused-core columns in both dimensions for sample preconcentration and determination of propranolol in human urine has been developed. On-line sample pretreatment and propranolol preconcentration were performed on an Ascentis Express RP-C-18 guard column (5 × 4.6 mm), particle size, 2.7 μm, with mobile phase acetonitrile/water (5:95, v/v) at a flow rate of 2.0 mL min(-1) and at a temperature of 50 °C. Valve switch from pretreatment column to analytical column was set at 4.0 min in a back-flush mode. Separation of propranolol from other endogenous urine compounds was achieved on the fused-core column Ascentis Express RP-Amide (100 × 4.6 mm), particle size, 2.7 μm, with mobile phase acetonitrile/water solution of 0.5% triethylamine, pH adjusted to 4.5 by means of glacial acetic acid (25:75, v/v), at a flow rate of 1.0 mL min(-1) and at a temperature of 50 °C. Fluorescence excitation/emission detection wavelengths were set at 229/338 nm. A volume of 1,500 μL of filtered urine sample solution was injected directly into the column-switching HPLC system. The total analysis time including on-line sample pretreatment was less than 8 min. The experimentally determined limit of detection of the method was found to be 0.015 ng mL(-1).

Electrogenerated chemiluminescence sensor for the determination of

An electrogenerated chemiluminescence (ECL) sensor for the determination of propranolol hydrochloride was fabricated by employing tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)32+) as an ECL signal producer and graphene as a modified material. The ECL sensor was fabricated by adsorbing Ru(bpy)32+ onto a mixture of graphene and Nafion. The introduction of conductive graphene into Nafion was found to greatly enhance the ECL intensity of Ru(bpy)32+ and the ECL intensity of Ru(bpy)32+ decreased in the presence of propranolol hydrochloride. Based on this phenomenon, a sensitive and stable ECL method was developed for the determination of propranolol hydrochloride by employing a Ru(bpy)32+-graphene-Nafion modified electrode. Under the optimized conditions, the ECL intensity was linear with the concentration of propranolol hydrochloride over a range of 1.0 × 10-10 to 5.0 × 10-9 mol L-1 with a detection limit of 3 × 10-11 mol L-1. The ECL sensor exhibited long-term stability with a relative standard deviation of 4.1% for sixteen continuous determinations of 2.0 × 10-9 mol L-1 propranolol hydrochloride. The developed method has been successfully applied to the determination of propranolol hydrochloride in pharmaceutical samples.