Two dimensional chromatography mass spectrometry: Quantitation of chiral shifts in metabolism of propranolol in bioanalysis.

In this study a heart-cutting 2D-LC method was successfully developed and optimized in order to discriminate and quantitate (S)-propranolol, (R)-propranolol, and its hydroxy metabolites, namely the isomeric (S)-4'­hydroxy propranolol, (R)-4'­hydroxy propranolol, (S)-5'­hydroxy propranolol, (R)-5'­hydroxy propranolol, (S)-7'-hydroxy propranolol, and (R)-7'­hydroxy propranolol in one chromatographic run. Thereby, experiments investigating chiral discrimination in ring hydroxylation of propranolol were made feasible. Analysis of human urine samples after administration of a single oral dose of 40 mg of propranolol clearly revealed considerable chiral shifts in propranolol and its 4'-, 5'-, and 7'-hydroxy metabolites. Furthermore, the excretion rates of the individual (S)- and (R)-enantiomers were continuously monitored over 24 h post administration. Studies were performed utilizing a 2D-LC system hyphenated to a triple quadrupole mass spectrometer. The chromatographic system was endued with a reversed phase column (phenyl-hexyl) in first dimension and a teicoplanin based chiral column in second dimension. The method was basically validated and successfully evaluated as robust. Calibration was performed achieving accuracy between 80% and 120%. Maximal excretion rates of (S)-propranolol, (R)-propranolol, (S)-4'­hydroxy propranolol, (R)-4'­hydroxy propranolol, (S)-5'­hydroxy propranolol, (R)-5'­hydroxy propranolol, and (R)-7'­hydroxy propranolol were 237 ng/min, 281 ng/min, 4 ng/min, 4 ng/min, 1 ng/min, 9 ng/min, and 3 ng/min, respectively.

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.

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.

SFC-MS/MS as an orthogonal technique for improved screening of polar analytes in anti-doping control.

HPLC is considered the method of choice for the separation of various classes of drugs. However, some analytes are still challenging as HPLC shows limited resolution capabilities for highly polar analytes as they interact insufficiently on conventional reversed-phase (RP) columns. Especially in combination with mass spectrometric detection, limitations apply for alterations of stationary phases. Some highly polar sympathomimetic drugs and their metabolites showed almost no retention on different RP columns. Their retention remains poor even on phenylhexyl phases that show different selectivity due to π-π interactions. Supercritical fluid chromatography (SFC) as an orthogonal separation technique to HPLC may help to overcome these issues. Selected polar drugs and metabolites were analyzed utilizing SFC separation. All compounds showed sharp peaks and good retention even for the very polar analytes, such as sulfoconjugates. Retention times and elution orders in SFC are different to both RP and HILIC separations as a result of the orthogonality. Short cycle times could be realized. As temperature and pressure strongly influence the polarity of supercritical fluids, precise regulation of temperature and backpressure is required for the stability of the retention times. As CO2 is the main constituent of the mobile phase in SFC, solvent consumption and solvent waste are considerably reduced. Graphical Abstract SFC-MS/MS vs. LC-MS/MS.

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.

Vortex-assisted liquid-liquid extraction combined with field-amplified sample injection and sweeping micellar electrokinetic chromatography for improved determination of ß-blockers in human urine.

A new micellar electrokinetic chromatography (MEKC) method was developed and validated for the analysis of carvedilol and propranolol in human urine samples. In this study, vortex-assisted liquid-liquid extraction (VALLE) coupled with field-amplified sample injection and sweeping was employed for biological sample clean-up and sensitivity enhancement in MEKC. After VALLE, the urine samples were analyzed by MEKC. Tris-phosphate buffer (60mmolL(-1), pH 2.0) containing 40% (v/v) methanol was first filled into an uncoated fused-silica capillary (56cm, 50µm i.d.). The pretreated urine sample was loaded by electrokinetic injection (10kV, 250s). The stacking and separation were performed using Tris-phosphate buffer (30mmolL(-1), pH 3.0) containing 30% (v/v) methanol and 50mmolL(-1) sodium dodecyl sulfate (SDS) at -25kV. Detection was carried out at 195 and 214nm for carvedilol and propranolol, respectively. The suggested method is linear (r(2)≥0.997) over a dynamic range of 0.005-1µgmL(-1) in urine. The intra- and inter-day relative standard deviation and relative error values of the method were below 20%, which shows good precision and accuracy. Finally, this method was successfully applied to the analysis of real urine samples.

Effects of (R)- and (S)-propranolol hydrochloride enantiomers on the resonance Rayleigh scattering spectra with erythrosine B as probe and their analytical applications.

Propranolol, a chiral drug with two configurations, i.e., (R)-propranolol hydrochloride (RPH) and (S)-propranolol hydrochloride (SPH), has racemes that can be used in clinical diagnosis due to their synergistic effects. SPH has a ß-receptor blocking effect, and RPH has an antiarrhythmic effect. In pH 4.6 Britton-Robinson (BR) buffer solution, both RPH and SPH can react with erythrosine B to form 1:1 ion-association complexes. In the SPH-Ery B reaction system, a remarkable enhancement of the resonance Rayleigh scattering (RRS) signal located at 338 nm was observed. However, a similar phenomenon was not obvious and was unstable in the RPH-Ery B reaction system. Based on this result, a simple, novel and sensitive method for the determination of SPH was proposed based on the RRS technique. The linear range and limit of detection were 0.0680~4.0 µg mL(-1) and 20.6 ng mL(-1), respectively. Additionally, the spectroscopic approaches of frequency doubling scattering (FDS) and second-order scattering (SOS) were also proposed for SPH detection in this article. The interaction information regarding the mechanism of the reaction, suitable reaction conditions, influencing factors and the effects of mixed solutions were our investigation aims. The method had been applied to the determination of SPH in fresh serum and urine samples of healthy human subjects with satisfactory results.

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.

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).

Combined data mining strategy for the systematic identification of sport drug metabolites in urine by liquid chromatography time-of-flight mass spectrometry.

The development of comprehensive methods able to tackle with the systematic identification of drug metabolites in an automated fashion is of great interest. In this article, a strategy based on the combined use of two complementary data mining tools is proposed for the screening and systematic detection and identification of urinary drug metabolites by liquid chromatography full-scan high resolution mass spectrometry. The proposed methodology is based on the use of accurate mass extraction of diagnostic ions (compound-dependent information) from in-source CID fragmentation without precursor ion isolation along with the use of automated mass extraction of accurate-mass shifts corresponding to typical biotransformations (non compound-dependent information) that xenobiotics usually undergo when metabolized. The combined strategy was evaluated using LC-TOFMS with a suite of nine sport drugs representative from different classes (propranolol, bumetanide, clenbuterol, ephedrine, finasteride, methoxyphenamine, methylephedrine, salbutamol and terbutaline), after single doses administered to rats. The metabolite identification coverage rate obtained with the systematic method (compared to existing literature) was satisfactory, and provided the identification of several non-previously reported metabolites. In addition, the combined information obtained helps to minimize the number of false positives. As an example, the systematic identification of urinary metabolites of propranolol enabled the identification of up to 24 metabolites, 15 of them non previously described in literature, which is a valuable indicator of the usefulness of the proposed systematic procedure.

Simultaneous and sensitive capillary electrophoretic enantioseparation of three ß-blockers with the combination of achiral ionic liquid and dual CD derivatives.

Successful simultaneous enantioseparation and sensitive determination of three ß-blockers (PIN, OX and PRO), have been achieved by capillary electrophoresis using an achiral ionic liquid, [GTMA]Cl, as a modifier to cooperate with dual CDs containing DM-ß-CD and TM-ß-CD. The influence of aIL was investigated in details, including various aILs, the concentration of aIL and molar ratio of aIL to CD. The ratio of DM-ß-CD to TM-ß-CD in dual CDs was also discussed. DM-ß-CD and TM-ß-CD favor the enantioseparations of PIN/OX and PRO, respectively. Meanwhile, the presence of [GTMA]Cl was found to play a key role in enantioseparations, and it widened the scope of application of DM-ß-CD and TM-ß-CD. Furthermore, FESI as an effective on-line sample enrichment technique was developed to improve the detection sensitivity. Under the optimum conditions, the detection limits of the three pairs of enantiomers range from 0.10 to 0.65 nM, which are much lower than those in the conventional methods. Eventually, the proposed method was successfully applied to the analysis of spiked urine sample with good recoveries.

Pharmacokinetics of propranolol hydrochlorid in human urine by capillary electrophoresis coupled with electrochemiluminescence.

A novel method for the determination of propranolol hydrochlorid (PRO) in human urine was developed using capillary electrophoresis coupled with electrochemiluminescence detection (CE-ECL). The parameters that affected the separation and detection were optimized. Under the optimal conditions, the linear range for PRO was from 0.003 to 2 µg/mL (r(2) = 0.9993), and the detection limit was 1.3 ng/mL (S/N = 3). The method was successfully applied to the study of the pharmacokinetics of PRO in human urine. The relative standard deviations of ECL intensity and migration time were 2.6 and 2.1%, respectively (1.0 µg/mL PRO, n = 6). The recovery was between 96.71 and 97.30%. The peak excretion rate in urine was observed during the 0.5-1 h after oral administration of a 10-mg PRO tablet and the urinary excretion ratio of PRO was 13.6% within 12 h. The method was simple, rapid, economical and sensitive, and may improve the detection of PRO as a doping agent in sports.

Extraction and preconcentration of beta-blockers in human urine for analysis with high performance liquid chromatography by means of carrier-mediated liquid phase microextraction.

A novel method was developed for the analysis of four beta-blockers, namely sotalol, carteolol, bisoprolol, and propranolol, in human urine by coupling carrier-mediated liquid phase microextraction (CM-LPME) to high performance liquid chromatography (HPLC). By adding an appropriate carrier in organic phase, simultaneous extraction and enrichment of hydrophilic (sotalol, carteolol, and bisoprolol) and hydrophobic (propranolol) drugs were achieved. High enrichment factors were obtained by optimizing the compositions of the organic phase, the acceptor solution, the donor solution, the stirring rate, and the extraction time. The linear ranges were from 0.05 to 10.0 mg L(-1) for sotalol and carteolol, and from 0.05 to 8.0 mg L(-1) for bisoprolol and propranolol. The limits of detection (S/N=3) were 0.01 mg L(-1) for sotalol, carteolol, and bisoprolol, and 0.005 mg L(-1) for propranolol. The relative standard deviations were lower than 6%. The developed method exhibited high analyte preconcentration and excellent sample clean-up effects with little solvent consumption and was found to be sensitive and suitable for simultaneous determination of the above four drugs spiked in human urine. Furthermore, the successful analysis of propranolol in real urine specimens revealed that the determination of beta-blockers in human urine is feasible using the present method.

[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.

Determination of propranolol enantiomers in plasma and urine by spectrofluorimetry and second-order standard addition method.

The determination of propranolol enantiomers in human plasma and urine by spectrofluorimetry and a second-order standard addition method is described. The methodology is based on chiral recognition of propranolol by formation of an inclusion complex with beta-cyclodextrin, a chiral auxiliary, in the presence of 1-butanol. The adopted strategy combines the use of PARAFAC, for extraction of the pure analyte signal, with the standard addition method, for determinations in the presence of an individual matrix effect caused by the quenching action of the proteins present in the plasma and urine. A specific PARAFAC model was built for each sample, in triplicate, and the scores were related to (R)-propranolol mole fraction using a linear regression in the standard addition method. Using a propranolol with concentration of 260 ng mL(-1), good results were obtained for determinations in the mole fraction range from 50 to 80% of (R)-propranolol, providing absolute errors between 0.4 and 3.6% for plasma and between 0.9 and 6.0% for urine.

Analysis of beta-agonists and beta-blockers in urine using hollow fibre-protected liquid-phase microextraction with in situ derivatization followed by gas chromatography/mass spectrometry.

A method using hollow fibre-protected liquid-phase microextraction (HF-LPME) with in situ derivatization followed by gas chromatography/mass spectrometry (GC/MS) was established for the analysis of beta-agonists and beta-blockers in urine. Because it can simultaneously extract and derivatize compounds of interest by methylbenzol and N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA) in HF-LPME, the approach overcomes the drawbacks of considerable time-consuming and tedious operation, meanwhile improves enrichment multiple. The optimized conditions were extraction for 20 min at 35 degrees C with 5.0 microL of mixed extraction solvent (methylbenzol/MSTFA=1:1, v/v) with stirring speed of 925 rpm in 5.0 mL sample under pH 12.0 and 14% (w/v) NaCl. The method provided very wide linear ranges (0.25-400 ng mL(-1)) and low detection limits in the range of 0.08-0.10 ng mL(-1) for clenbuterol, metoprolol and propranolol while enrichment factors reached up to 256. The analytes could be determined in spiked urine by the method with high extraction efficacy (93.79-109.04% recoveries) and precision (<9.70% RSD). It has a satisfactory result for metoprolol in practical human urine samples for a single-dose administration of 50 mg after 36 h. The proposed method only needs few microliters of organic solvent and derivatizing agent; the operation is simple, convenient and rapid for the trace analysis of beta-agonists and beta-blockers in biological fluids; it can be readily generalized for high sample throughput. So, it is hopeful that the study will facilitate the monitoring of beta-agonists and beta-blockers in the competition sports.

Simultaneous spectrofluorimetric determination of levodopa and propranolol in urine using feed-forward neural networks assisted by principal component analysis.

The simultaneous determination of levodopa (LD) and propranolol (PRO) using fluorescence spectrometric technique is described. The method involves measuring the natural fluorescence of these drugs in the micellar media of sodium dodecyl sulfate (SDS) using principal component analysis-feed-forward neural networks (PC-FFNNs). Experimental conditions such as effect of pH and SDS concentration were optimized. Under the optimum conditions, the linear determination ranges of LD and PRO are 2.0 x 10(-8) to 1.0 x 10(-5)mol L(-1) and 3.6 x 10(-9) to 1.8 x 10(-6)mol L(-1), respectively. A set of synthetic binary mixtures of LD and PRO was prepared and their concentrations were predicted by the proposed method. Satisfactory results were obtained by the combination of fluorescence technique with chemometrics methods. The method was successfully applied to the determination of LD and PRO in tap water and in urine samples.

High-throughput quantitative analysis by desorption electrospray ionization mass spectrometry.

A newly developed high-throughput desorption electrospray ionization (DESI) source was characterized in terms of its performance in quantitative analysis. A 96-sample array, containing pharmaceuticals in various matrices, was analyzed in a single run with a total analysis time of 3 min. These solution-phase samples were examined from a hydrophobic PTFE ink printed on glass. The quantitative accuracy, precision, and limit of detection (LOD) were characterized. Chemical background-free samples of propranolol (PRN) with PRN-d(7) as internal standard (IS) and carbamazepine (CBZ) with CBZ-d(10) as IS were examined. So were two other sample sets consisting of PRN/PRN-d(7) at varying concentration in a biological milieu of 10% urine or porcine brain total lipid extract, total lipid concentration 250 ng/microL. The background-free samples, examined in a total analysis time of 1.5 s/sample, showed good quantitative accuracy and precision, with a relative error (RE) and relative standard deviation (RSD) generally less than 3% and 5%, respectively. The samples in urine and the lipid extract required a longer analysis time (2.5 s/sample) and showed RSD values of around 10% for the samples in urine and 4% for the lipid extract samples and RE values of less than 3% for both sets. The LOD for PRN and CBZ when analyzed without chemical background was 10 and 30 fmol, respectively. The LOD of PRN increased to 400 fmol analyzed in 10% urine, and 200 fmol when analyzed in the brain lipid extract.

Determination of selected beta-receptor antagonists in biological samples by solid-phase extraction with cholesterolic phase and LC/MS.

A new method is presented for the determination of five selected beta-receptor antagonists by HPLC, which emphasizes sample preparation via retention on a new type of silica gel sorbent used for solid-phase extraction (SPE). Sorbents of this type were obtained by the chemical modification of silica gels of various porosities by cholesterol ligands. The cholesterol-based packing material was investigated by spectroscopic methods and elemental analysis. The recoveries obtained with the extraction procedure were optimum over a relatively broad sample pH range (3.08-7.50). Analytical factors such as the sample loading, the washing step and elution conditions, the concentration of beta-receptor antagonists to be extracted, and the type of sorbent were found to play significant roles in the sample preparation procedure and would therefore need to be controlled to achieve optimum recoveries of the analytes. Under optimum conditions, the recoveries of nadolol, acebutolol, esmolol, oxprenolol and propranolol from spiked buffers, blood and urine were reproducible and dependent on the polarity or hydrophilicity of the compounds. The above analytes were determined by reverse-phase high-performance liquid chromatography (HPLC) with UV and ESI-ion trap mass spectrometry (MS) detection. The described method was found to be suitable for the routine measurement of compounds that are both polar and basic, and can be applied for the analysis of biological samples such as urine and blood in clinical, toxicological or forensic laboratories. The recovery measurements were performed on spiked human urine and serum, and on real samples of mouse blood serum.

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.