A highly sensitive LC-MS/MS method capable of simultaneously quantitating celiprolol and atenolol in human plasma for a cassette cold-microdosing study.

A highly sensitive simultaneous quantitative method for a cassette cold-microdosing study on celiprolol and atenolol was developed with liquid chromatography-tandem mass spectrometry. The method utilizes a combination of solid-phase extraction (SPE) with strong cation exchange (SCX) cartridge columns and reversed-phase chromatography with an ODS analytical column. SCX-SPE cartridge columns (100 mg sorbent) were used for a selective extraction of celiprolol, atenolol and metoprolol (internal standard) from 500 µL of human plasma samples. Turbo-ion spray at positive mode was employed for the ionization of the drug compounds. Quantitation was performed on a triple quadrupole mass spectrometer by selected reaction monitoring with the transitions of m/z 380 to m/z 251 for celiprolol and m/z 267 to m/z 145 for atenolol. Separation of analytes was achieved on an ODS column (100 mm length × 2.1 mm id, 3 µm) by a gradient elution with 10 mM formic acid and methanol by varying their proportion at a flow rate of 0.2 mL/min. The method was validated in the range of 1-250 pg/mL for celiprolol and 2.5-250 pg/mL for atenolol and was successfully applied to the elucidation of pharmacokinetic profiling in a cold cassette microdosing study of the ß-blockers.

Simultaneous separation of eight beta-adrenergic drugs using titanium dioxide nanoparticles as additive in capillary electrophoresis.

The analysis is described for separating seven beta-adrenergic blocking agents (atenolol, celiprolol, clorprenaline, fenoterol, metoprolol, propranolol, terbutaline) and clenbuterol (sympathomimetic beta-2 receptor stimulating agonist, decongestant and bronchodilator, illicit anabolic used in athletics) by CE with UV detection. In order to simultaneously separate all analytes, Tris-H3PO4 solution was applied containing titanium dioxide nanoparticles (TiO2 NPs) as BGEs. The effects of important factors, such as concentration of TiO2 NPs, optimum pH, run buffer concentration, and separation voltage, were investigated so as to achieve best CE separation. The eight analytes could be well separated applying a separation voltage of 15 kV in 75 mM Tris-H3PO4 buffer at a pH of 2.40, containing 6.0 x 10(-6) g/mL TiO2 NPs. Under these optimal conditions, the RSDs for peak areas and for migration times were less than 2.7 and 2.3%, respectively. The detection limits were 0.1 microg/mL for celiprolol, 0.1 microg/mL for propranolol, 0.2 microg/mL for fenoterol, 1.0 microg/mL for atenolol, 1.0 microg/mL for clenbuterol, 1.0 microg/mL for clorprenaline, 1.0 microg/mL for metoprolol, and 1.0 microg/mL for terbutaline. The proposed method was successfully applied for the rapid CE determination of the frequently applied antihypertensive beta-blocking compounds atenolol, metoprolol, terbutaline, and propranolol in pharmaceutical tablets.

Experimental design for enantioselective separation of celiprolol by capillary electrophoresis using sulfated beta-cyclodextrin.

A capillary zone electrophoresis method was developed for the enantioseparation of celiprolol enantiomers, using a sulfated beta-cyclodextrin (beta-CD) as a chiral selector. The use of a coated capillary was necessary to achieve stable and reproducible enantioseparations. A central composite design was applied to optimize the method and four parameters were selected for this study: the buffer pH, the buffer concentration, the sulfated beta-CD concentration and the temperature. Resolution between celiprolol enantiomers as well as analysis time and generated current were established as responses. For each response, a model was obtained by a second-degree mathematical expression. From the models, the most favorable conditions were determined by optimizing the resolution between celiprolol enantiomers and by setting the two other responses at threshold values. Response surfaces were also used to assess the robustness of the analytical method around the optimal region. Successful results were obtained with a 52 mM acetate buffer at pH 4.0 in the presence of 3.0 mM sulfated beta-CD at a temperature of 19.5 degrees C. Under these optimized conditions, baseline separation of the celiprolol enantiomers was achieved in less than 10 min. The method showed good validation data in terms of precision, accuracy and linearity, and was found to be suitable in determining celiprolol enantiomers in pharmaceutical preparations and in biological fluids.

[Separation of celiprolol enantiomer by high performance liquid chromatography with urea derivative as chiral stationary phase].

Celiprolol enantiomer was resolved directly by using normal-phase HPLC with urea derivative as chiral stationary phase (CSP). The resolution condition was optimized by varying the content of ethanol and 1, 2-dichloroethane in the mobile phase. The effects of the two components on stereoselectivity factor (alpha) and stereochemical resolution factor (Rs) are demonstrated. The higher the 1,2-dichloroethane content the faster the elution of solute is, but the lower the values of alpha and Rs are. For a suitable content of ethanol in mobile phase, the maximum resolution factor (Rs) can be obtained. Ethanol is a strong proton-donor and proton-acceptor. Its strong hydrogen bond interaction with solute and CSP is important for the direct resolution. In order to obtain both the low retention time and a high Rs, we chose the mobile phase with n-hexane:1,2-dichloroethane:ethanol (V/V/V) = 77:21:2. Other organic modifiers such as methanol, iso-propanol, n-butanol and acetonitrile were also used. Iso-propanol, methanol and n-butanol showed longer retention time and lower values of alpha and Rs than ethanol. Acetonitrile is only a proton-acceptor and has weak hydrogen bond interaction with solute and CSP, so resolution wasn't obtained. The elution order of enantiomer was also discussed. We thought that the hydrogen bond interaction between solute and the (S)-val component of CSP may mainly control the chiral recognition. The interaction strength is different between (R)- and (S)-celiprolol, so the celiprolol enantiomer was resolved. And the elution order is S, R.