Validated HPLC-MS/MS method for determination of quetiapine in human plasma.

A validated, highly sensitive and selective high-pressure liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the quantitative determination of quetiapine (QUE) in human Na2EDTA plasma with mass spectrometry (MS) detection. Clozapine (CLO) was employed as an internal standard. Samples were extracted using solid phase extraction (SPE).

Validated HPLC-MS-MS method for simultaneous determination of atorvastatin and 2-hydroxyatorvastatin in human plasma-pharmacokinetic study.

Cholesterol-reducing statin drugs are the most frequently prescribed agents for reducing morbidity and mortality related to coronary heart disease. In this publication a validated, highly sensitive, and selective isocratic HPLC method is reported for quantitative determination of the major statin drug atorvastatin (ATV) and its metabolite 2-hydroxyatorvastatin (HATV). Detection was performed with an electrospray ionization triple-quadrupole mass spectrometer equipped with an ESI interface operating in positive-ionization mode.

Validated HPLC-MS/MS method for simultaneous determination of simvastatin and simvastatin hydroxy acid in human plasma.

Cholesterol lowering statin drugs are the most frequently prescribed agents for reducing morbidity and mortality related to coronary heart disease. This publication presents a validated, highly sensitive and selective isocratic HPLC method for the quantitative determination of the major statin drug simvastatin (SIM) and its metabolite simvastatin hydroxy acid (SIMA). Detection was performed on an electrospray ionization triple quadrupole mass spectrometer equipped with an ESI interface operated in positive and negative ionization mode.

Validated HPLC-MS-MS method for determination of azithromycin in human plasma.

A validated, highly sensitive, and selective HPLC method with MS-MS detection has been developed for quantitative determination of azithromycin (AZI) in human Na2EDTA plasma. Roxithromycin (ROX) was used as internal standard. Human plasma containing AZI and internal standard was ultrafiltered through Centrifree Micropartition devices and the concentration of AZI was determined by isocratic HPLC-MS-MS.

Risk assessment of mixtures: possibility of prediction of interaction between chemicals.

Objectives: Potentiation, inhibition, antagonism, synergism or other interactions of chemicals in an organism may significantly affect the toxicity of chemical mixtures. Therefore, a suitable physicochemical parameter is sought as a predictor of these effects.

Methods: Acute toxicity EC50 (mol/l) was used as an index of toxic hazard.

Prediction of acute toxicity of chemicals in mixtures: worms Tubifex tubifex and gas/liquid distribution.

The aim of this contribution is to support our proposal of the procedure for predicting acute toxicity of binary mixtures by QSAR analysis techniques. The changes of a mixture composition are described by molar ratio R and visualized in the R-plot (QCAR--quantitative composition-activity relationships). The approach was inspired by Rault and Dalton's laws, their positive and negative deviations in the behavior of a mixture of real gases, by Loewe and Muischnek isoboles and by the Finney test of additivity.