Electrically assisted liquid-phase microextraction combined with capillary electrophoresis for quantification of propranolol enantiomers in human body fluids.

In this study, electromembrane extraction (EME) combined with cyclodextrin (CD)-modified capillary electrophoresis (CE) was applied for the extraction, separation, and quantification of propranolol (PRO) enantiomers from biological samples. The PRO enantiomers were extracted from aqueous donor solutions, through a supported liquid membrane (SLM) consisting of 2-nitrophenyl octyl ether (NPOE) impregnated on the wall of the hollow fiber, and into a 20-µL acidic aqueous acceptor solution into the lumen of hollow fiber. Important parameters affecting EME efficiency such as extraction voltage, extraction time, pH of the donor and acceptor solutions were optimized using a Box-Behnken design (BBD). Then, under these optimized conditions, the acceptor solution was analyzed using an optimized CD-modified CE. Several types of CD were evaluated and best results were obtained using a fused-silica capillary with ammonium acetate (80 mM, pH 2.5) containing 8 mM hydroxypropyl-ß-CD as a chiral selector, applied voltage of 18 kV, and temperature of 20°C. The relative recoveries were obtained in the range of 78-95%. Finally, the performance of the present method was evaluated for the extraction and determination of PRO enantiomers in real biological samples.

Preparation and evaluation of propranolol molecularly imprinted solid-phase microextraction fiber for trace analysis of beta-blockers in urine and plasma samples.

An improved multiple co-polymerization technique was developed to prepare a novel molecularly imprinted polymer (MIP)-coated solid-phase microextraction (SPME) fiber with propranolol as template. Investigation was performed for the characteristics and application of the fibers. The MIP coating was highly crosslinked and porous with the average thickness of only 25.0 microm. Consequently, the adsorption and desorption of beta-blockers within the MIP coating could be achieved quickly. The specific selectivity was discovered with the MIP-coated fibers to propranolol and its structural analogues such as atenolol, pindolol, and alprenolol. In contrast, only non-specific adsorption could be shown with the non-imprinted polymer (NIP)-coated fibers, and the extraction efficiencies of propranolol and pindolol with the MIP-coated fibers were higher markedly than that with the commercial SPME fibers. A MIP-coated SPME coupled with high-performance liquid chromatography (HPLC) method for propranolol and pindolol determination was developed under the optimized extraction conditions. Linear ranges for propranolol and pindolol were 20-1000 microg L(-1) and detection limits were 3.8 and 6.9 microg L(-1), respectively. Propranolol and pindolol in the spiked human urine and plasma samples, extracted with organic solvent firstly, could be simultaneous monitored with satisfactory recoveries through this method.

Magnetic multi-walled carbon nanotube poly(styrene-co-divinylbenzene) for propranolol extraction and separation by capillary electrophoresis.

AIM: The preparation of magnetic multi-walled carbon nanotube poly(styrene-co-divinylbenzene) for propranolol magnetic solid-phase extraction is described. MATERIALS & METHODS: A study comparing propranolol adsorption and desorption was performed with only magnetic multi-walled carbon nanotubes, and different poly(styrene-co-divinylbenzene) with and without magnetic multi-walled carbon nanotubes. Enantiomeric separation of propranolol took place by cyclodextrin-modified capillary electrophoresis and the method was validated in spiked human urine samples. RESULTS: Recovery values raised when styrene/divinylbenzene millimoles ratio was 19.57:15.80. Enrichment factors increased up to approximately 100, detection limits were 13.8 and 10.5 ng ml-1 for R- and S-propranolol respectively, quantitation limits were 46.0 and 34.8 ng ml-1 for R- and S-propranolol respectively, recoveries from spiked samples ranged from 90.9 to 109.0%, and relative standard deviations were <6.3%. CONCLUSION: This methodology was proven to be more effective than classical solid-phase extraction strategies and may be applied to other kind of biological samples.

Water-compatible graphene oxide/molecularly imprinted polymer coated stir bar sorptive extraction of propranolol from urine samples followed by high performance liquid chromatography-ultraviolet detection.

Due to the high selectivity and stability, molecularly imprinted polymers (MIPs) have been successfully applied in stir bar sorptive extraction (SBSE) as a special coating to improve the selective extraction capability for target analytes. However, traditional MIPs usually suffer from incompatibility in aqueous media and low adsorption capacity, which limit the application of MIP coated stir bar in aqueous samples. To solve these problems, a water-compatible graphene oxides (GO)/MIP composite coated stir bar was prepared in this work by in situ polymerization. The prepared water-compatible GO/MIP coated stir bar presented good mechanical strength and chemical stability, and its recognition ability in aqueous samples was improved due to the polymerization of MIP in water environment, the adsorption capacity for target analytes was also increased by the addition of GO in MIP pre-polymer solution. Based on it, a method of water-compatible GO/MIP coated stir bar sorptive extraction combined with high performance liquid chromatography-ultraviolet detector (HPLV-UV) was proposed for the analysis of propranolol (PRO) in aqueous solution. The influencing factors of SBSE, such as sample pH, salt effect, stirring rate, extraction time, desorption solvent and desorption time, were optimized, and the analytical performance of the developed SBSE-HPLC-UV method was evaluated under the optimized conditions. The limit of detection (LOD) of the proposed method for PRO was about 0.37 µg L(-1), and the enrichment factor (EF) was 59.7-fold (theoretical EF was 100-fold). The reproducibility was also investigated at concentrations of 5 µg L(-1) and the relative standard deviation (RSD) was found to be 7.3% (n=7). The proposed method of GO/MIP coating-SBSE-HPLC-UV was successfully applied for the assay of the interested PRO drug in urine samples, and further extended to the investigation of the excretion of the drugs by monitoring the variation of the concentration of PRO in urine within 10h after drug-taking.

Determination of propranolol and carvedilol in urine samples using a magnetic polyamide composite and LC-MS/MS.

AIM: ß-blockers are compounds that bind with adrenoreceptors hindering their interaction with adrenalin and noradrenalin. They are clinically relevant and they are also used in some sport as doping agents. RESULTS: A new method based on the combination of dispersive micro-solid phase extraction and LC-MS/MS has been developed to determine propranolol and carvedilol in urine samples. For this purpose a magnetic-polyamide composite is synthesized and used as sorbent. Working under the optimum conditions, the method provides limits of detection and quantification in the range of 0.1-0.15 µg/l and 0.3-0.5 µg/l, for carvedilol and propranolol, respectively. The precision, expressed as RSD, was better than 9.6% and the relative recoveries varied between 73.7 and 81.3%. CONCLUSION: The methodology is appropriate for the determination of ß-blockers in urine samples at the low microgram per liter range for therapeutic purposes.

Optimization of selectivity in micellar chromatographic procedures for the determination of drugs in urine by direct injection.

Selectivity was optimized for the determination of drugs in urine by direct injection micellar chromatography through changes in specific mobile phase parameters. The rôle of mobile phase pH and the type of surfactant used for mobile phase preparation was investigated. The retention of the urine matrix was found to be minimal between pH 5.5 and 7.5. The non-ionic surfactant, polyoxyethylene 23 lauryl ether (Brij 35), was found to be the surfactant of choice for the separation of drugs from urine. Favourable retention of both the urine background and the analyte was achieved with this surfactant. Micellar mobile phases of optimal composition were used to develop chromatographic procedures for the determination of furosemide, hydrochlorothiazide and propranolol in urine. Good accuracy (98-102% of drug recovered), precision (1-4% RSD) and linearity were obtained for all methods. Limits of detection for all drugs were adequate.

[Two dimensional capillary zone electrophoresis/micellar electrokinetic capillary chromatography for the analysis of drugs and their enantiomers in urine samples].

A new two dimensional method, which interfaced capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC) by a polytetrafluoroethylene (PTFE) tube with a hole of 30-40 microm diameter on the top, was developed for the analysis of drugs and their enantiomers. The CZE was used as the first dimensional separation, from which the eluting components were transferred and further analyzed by MEKC. Online dual concentration method, pH junction-sweeping, was used to avoid sample zone diffusion at the interface. The separation efficiencies and detection limits were (2.8-4.3) x 10(4)/m and 0.015-0.052 mg/L, respectively. The proposed method has successfully demonstrated that in the separation of four drugs and their enantiomers in urine samples, the relative standard deviations (RSDs) of peak area and migration time were in the ranges of 1.7%-3.8% and 1.3%-4.6%, respectively. The method was proved to have good reproducibility, high sensitivity and resolution, large peak capacity. It is reliable and suitable to separate and determine multi-drugs and their enantiomers in urine samples simultaneously.

Pharmacodynamics of propranolol in renal failure.

The pharmacodynamics of propranolol were studied in patients with renal functional impairment. (14)C-labelled propranolol was given either intravenously or by mouth and the disappearance rates of propranolol, 4-hydroxypropranolol, and total radioactive metabolites measured. The renal clearance of total radioactive compounds is directly related to renal function. The half-life of total radioactivity is greatly lengthened in the presence of severe renal failure while the half-lives of the pharmacologically active propranolol and 4-hydroxymetabolite are slightly reduced. There is a suggestion that the absorption of propranolol is delayed in renal failure. No known pharmacological action or side effects from the other metabolic products of propranolol have been recognized. There is still too little well-documented evidence concerning the beta-blocking activity of the unidentified major metabolites of propranolol to suggest any alteration in the dosage regimen used in renal failure.