Determination of β-blockers in pharmaceutical and human urine by capillary electrophoresis with electrochemiluminescence detection and studies on the pharmacokinetics

Electrochemical screening of selected β-blockers at a polarized liquid-liquid interface

This paper describes the electrochemical behavior of five β-blockers at the polarized liquid-liquid interface formed between aqueous solution (sodium chloride solution or Britton-Robinson buffers) and bis(triphenylphosphoranylidene)ammonium tetrakis(4-chlorophenyl)borate (BTPPATPBCl) dissolved in 1,2-dichloroethane (the organic phase). All measurements reported in this work were conducted using cyclic voltammetry (CV). The effects of the concentration of analytes, the pH of the aqueous phase, and applied electrochemical parameters on the analytical performance of the studied system are studied and discussed. The linear dynamic ranges (LDRs) of the studied β-blockers were in the range of 5-200 μmol L-1 and the lowest limit of detection (LOD) value was determined for pindolol (LOD = 1.96 μM μmol L-1). The highest LOD value was 4.96 μmol L-1 found for nebivolol. In addition, physicochemical parameters such as the formal Galvani potential difference (Δaqorgϕ), formal Gibbs free energies of the ion transfer reaction (ΔaqorgG') and partition coefficients (log P'aq/org) for all studied molecules were determined. The latter were compared and correlated with the available literature values of log Poctanol. Finally, a standard addition method was used to determine the concentration of nebivolol in pharmaceutical preparations using a platform based on the electrified liquid-liquid interface.

Rapid and sensitive tapered-capillary microextraction combined to on-line sample stacking-capillary electrophoresis for extraction and quantification of two beta-blockers in human urine

A tapered-capillary microextraction (tCap-μEx) combining with field-amplified stacking (FASI) method for CE analysis was developed. The tCap-μEx method is based on the construction of a micro solid phase extraction (SPE) column by narrowing the end of a silica capillary from 530µm (inner diameter) to 20µm, enabling the packing of 45µm sorbent particles without a frit. Various parameters that may affect the microextraction and FASI-CE analysis have been investigated and optimized. This study shows that microextraction exhibits advantages of small sample and sorbent volumes (less than 200μL sample and 2μL sorbent) and fast extraction time of 6min. The method was successfully applied for efficient determination of atenolol and metoprolol in human urine samples, with recovery of 93.7-105.5% and RSD (n=3) lower than 8.5%. Twenty-one-fold and nineteen-fold average enhancement of detection sensitivity was achieved for atenolol and metoprolol, respectively, versus the CE method without tCap-μEx and FASI. The method is environmentally friendly and allows reuse of the sorbent at least 8 times without an obvious loss in performance. The results indicate that the proposed method could be potentially applied in a wide range of doping control, clinical, forensic toxicology, food analysis and environmental analyses.

Detection of Metoprolol in Human Biofluids and Pharmaceuticals via Ion-Transfer Voltammetry at the Nanoscopic Liquid/Liquid Interface Array

Metoprolol (MTP) is one of the most widely used antihypertensive drugs yet banned to use in sport competition. Therefore, there has been an increasing demand for developing simple, rapid, and sensitive methods suited to the identification and quantification of MTP in human biofluids. In this work, ultrathin silica nanochannel membrane (SNM) with perforated channels was employed to support nanoscale liquid/liquid interface (nano-ITIES) array for investigation of the ion-transfer voltammetric behavior of MTP and for its detection in multiple human biofluids and pharmaceutical formulation. Several potential interfering substances, including small molecules, d-glucose, urea, ascorbic acid, glycine, magnesium chloride, sodium sulfate and large molecules, bovine serum albumin (BSA), were chosen as models of biological interferences to examine their influence on the ion-transfer current signal of MTP. The results confirmed that the steady-state current wave barely changed in the presence of small molecules. Although BSA displayed an apparent blockade on the transfer of MTP, the accurate determination of MTP in multiple human biofluids (i.e., urine, serum and whole blood) and pharmaceutical formulation were still feasible, thanks to the molecular sieving and antifouling abilities of SNM. A limit of detection (LOD) within the physiological level of MTP during therapy could be achieved for all cases, i.e., 0.5 and 1.1 μM for 100 times diluted urine and serum, respectively, and 2.2 μM for 1000 times diluted blood samples. These results demonstrated that the nano-ITIES array behaved as a simplified and integrated detection platform for ionizable drug analysis in complex media.

Applications of capillary electrophoresis with chemiluminescence detection in clinical, environmental and food analysis. A review

This paper reviews the latest developments and analytical applications of chemiluminescence detection coupled to capillary electrophoresis (CE-CL). Different sections considering the most common CL systems have been included, such as the tris(2,2'-bipyridine)ruthenium(II) system, the luminol and acridinium derivative reactions, the peroxyoxalate CL or direct oxidations. Improvements in instrumental designs, new strategies for improving both resolution and sensitivity, and applications in different fields such as clinical, pharmaceutical, environmental and food analysis have been included. This review covers the literature from 2010 to 2015.

Detection limit enhancement of antiarrhythmic drugs in human plasma using capillary electrophoresis with dispersive liquid–liquid microextraction and field-amplified sample stacking method

Background: A new capillary zone electrophoresis (CZE) with ultraviolet detection method has been developed and validated for the analysis of four antiarrhythmic drugs in human plasma samples. Methods: In this study, a dispersive liquid–liquid microextraction (DLLME) coupled with field-amplified sample stacking (FASS) was employed for biological samples clean-up and sensitivity enhancement in CZE. Results: Under optimum DLLME-FASS-CZE conditions, enhancement factors were in the range of 157–314. The method was validated over the concentration range of 20–800 ng/ml in human plasma. Inter- and intra-day precision and the accuracy were less than 20%; the detection limits ranged from 2.5 to 4.7 ng/ml. Furthermore, the validated method was successfully applied to the detection of studied drugs in patients’ plasma samples.

Salt-assisted LLE combined with field-amplified sample stacking in CE for improved determination of beta blocker drugs in human urine

Background: A simple and sensitive CE method was developed and validated for the analysis of some beta blockers in human urine. Methods: In this study, salting-out assisted LLE combined with field-amplified sample stacking method was employed for biological sample clean-up and sensitivity enhancement in CE. Results: Under the optimal conditions good linearity (r2 ≥0.998) was obtained, within 0.025–1 µg/ml for propranolol and metoprolol, and within 0.05–1 µg/ml for carvedilol in urine samples. LODs and LLOQs ranged from 0.005 to 0.015 µg/ml, and from 0.025 to 0.05 µg/ml, respectively. The RSDs of intra- and inter-day analysis of examined compounds were less than 4.0%. The recoveries were in the range of 98–119%. Conclusion: The validated method is successfully applied to determine propranolol, metoprolol and carvedilol in human urine samples obtained from the patients who received these drugs.

A validated, rapid UPLC-MS/MS method for simultaneous ivabradine, reboxetine, and metoprolol analysis in human plasma and its application to clinical trial samples

A recent clinical trial assessing human autonomic cardiovascular regulation applied pacemaker channel inhibition with ivabradine, norepinephrine transporter blockade with reboxetine, and beta-adrenoreceptor blockade with metoprolol. To verify patient adherence, we developed and validated a fast UPLC-MS/MS assay measuring all three compounds simultaneously. Deuterium-labeled drugs, d3-ivabradine, d5-reboxetine and d7-metoprolol, served as internal standards. Sample preparation of 200μL human plasma consisted of a single liquid-liquid extraction step by means of ethyl acetate. Chromatographic separation was performed on a 50-mm long BEH C18 column with gradient elution using a mixture of water and methanol each containing 2mM ammonium acetate over 4.5min. The mass spectrometer was operated in the positive electrospray ionization (ESI+) mode. Characteristic product ions resulting from collision-induced dissociation of unlabeled and deuterium-labeled drugs with argon were used for quantification in the selected-reaction monitoring mode. We validated the method according to the European Medicines Agency (EMA) guideline on bioanalytical method validation over the range from 1ng/mL to 500ng/mL for all three analytes. Linear responses with correlation coefficients>0.99 over that range were acquired. The LOQ value was 1ng/mL for each drug. Regulatory criteria for accuracy (80-120%) and precision (RSD<15%) were met for all drugs. The internal standard-normalized matrix factor was close to 1 for low and high analyte concentrations. We successfully measured ivabradine, reboxetine, and metoprolol concentrations in 107 human plasma samples from a clinical trial. Quality control samples processed in parallel confirmed the method's reliability in a clinical setting.