A new simple spectrophotometric method was developed for the determination of binary mixtures without prior separation.The method is based on the generation of ratio spectra of compound X by using a standard spectrum ...A new simple spectrophotometric method was developed for the determination of binary mixtures without prior separation.The method is based on the generation of ratio spectra of compound X by using a standard spectrum of compound Y as a divisor.The peak to trough amplitudes between two selected wavelengths in the ratio spectra are proportional to concentration of X without interference from Y.The method was demonstrated by determination of two drug combinations.The first consists of the two antihyperlipidemics：atorvastatin calcium（ATV） and ezetimibe（EZE）,and the second comprises the antihypertensives：candesartan cilexetil（CAN） and hydrochlorothiazide（HCT）.For mixture 1,ATV was determined using 10 μg/mL EZE as the divisor to generate the ratio spectra,and the peak to trough amplitudes between 231 and 276 nm were plotted against ATV concentration.Similarly,by using 10 μg/mL ATV as divisor,the peak to trough amplitudes between 231 and 276 nm were found proportional to EZE concentration.Calibration curves were linear in the range 2.5-40 mg/mL for both drugs.For mixture 2,divisor concentration was 7.5 μg/mL for both drugs.CAN was determined using its peak to trough amplitudes at 251 and 277 nm,while HCT was estimated using the amplitudes between 251 and 276 nm.The measured amplitudes were linearly correlated to concentration in the ranges 2.5-50 and 1-30 μg/mL for CAN and HCT,respectively.The proposed spectrophotometric method was validated and successfully applied for the assay of both drug combinations in several laboratory-prepared mixtures and commercial tablets.展开更多
Quantitative determination of hydrochlorothiazide (HCTZ) and candesartan (CDS) in human plasma in volunteers was performed using a sensitive, selective and specific LC-MS method which has been developed and validated ...Quantitative determination of hydrochlorothiazide (HCTZ) and candesartan (CDS) in human plasma in volunteers was performed using a sensitive, selective and specific LC-MS method which has been developed and validated before the study. The study was performed by means of a liquid chromatograph Shimadzu Prominence equipped with a mass spectrometer LCMS-2020. Analytical column PerfectBond ODS-HD HPLC-column 5 μm 250 × 3.0 mm with a pre-column cartridge PerfectBond ODS-HD 5 μm 10 × 3.0 mm, double source of ionization for LCMS-2020 (electrospray (ESI) and chemical (APCI)) and software LabSol LCMS V5 LCMS2020 systempack were used. The low limit of the quantitative determination for HCTZ and CDS made up 10 ng/ml. m/z for CDS 441.20—positive scan, m/z for HCTZ 295.90—negative scan. The method has been applied to a pharmacokinetic study of 12.5 mg HCTZ and 16 mg CDS tablet in healthy volunteers.展开更多
A validated ultra-performance liquid chromatography mass spectrometric method （UPLC-MS/MS） was used for the simultaneous quantitation of candesartan （CN） and hydrochlorothiazide （HCT） in human plasma. The analys...A validated ultra-performance liquid chromatography mass spectrometric method （UPLC-MS/MS） was used for the simultaneous quantitation of candesartan （CN） and hydrochlorothiazide （HCT） in human plasma. The analysis was performed on UPLC-MS/MS system using turbo ion spray interface. Negative ions were measured in multiple reaction monitoring （MRM） mode. The analytes were extracted using a liquid-liquid extraction （LLE） method by using 0.1 mL of plasma volume. The lower limit of quantitation for CN and HCT was 1.00 ng/mL whereas the upper limit of quantitation was 499.15 ng/mL and 601.61 ng/mL for CN and HCT respectively. CN d4 and HCT-13Cd2 were used as the internal standards for CN and HCT respectively. The chromatography was achieved within 2.0 min run time using a C18 Pheno-menex, Gemini NX （100 mm ~ 4.6 mm, 5 mm） column with organic mixture：buffer solution （80：20, v/v） at a flow rate of 0.800 mL/min. The method has been successfully applied to establish the bioequivalence of candesartan cilexetil （CNC） and HCT immediate release tablets with reference product in human subjects.展开更多
文摘A new simple spectrophotometric method was developed for the determination of binary mixtures without prior separation.The method is based on the generation of ratio spectra of compound X by using a standard spectrum of compound Y as a divisor.The peak to trough amplitudes between two selected wavelengths in the ratio spectra are proportional to concentration of X without interference from Y.The method was demonstrated by determination of two drug combinations.The first consists of the two antihyperlipidemics：atorvastatin calcium（ATV） and ezetimibe（EZE）,and the second comprises the antihypertensives：candesartan cilexetil（CAN） and hydrochlorothiazide（HCT）.For mixture 1,ATV was determined using 10 μg/mL EZE as the divisor to generate the ratio spectra,and the peak to trough amplitudes between 231 and 276 nm were plotted against ATV concentration.Similarly,by using 10 μg/mL ATV as divisor,the peak to trough amplitudes between 231 and 276 nm were found proportional to EZE concentration.Calibration curves were linear in the range 2.5-40 mg/mL for both drugs.For mixture 2,divisor concentration was 7.5 μg/mL for both drugs.CAN was determined using its peak to trough amplitudes at 251 and 277 nm,while HCT was estimated using the amplitudes between 251 and 276 nm.The measured amplitudes were linearly correlated to concentration in the ranges 2.5-50 and 1-30 μg/mL for CAN and HCT,respectively.The proposed spectrophotometric method was validated and successfully applied for the assay of both drug combinations in several laboratory-prepared mixtures and commercial tablets.
文摘Quantitative determination of hydrochlorothiazide (HCTZ) and candesartan (CDS) in human plasma in volunteers was performed using a sensitive, selective and specific LC-MS method which has been developed and validated before the study. The study was performed by means of a liquid chromatograph Shimadzu Prominence equipped with a mass spectrometer LCMS-2020. Analytical column PerfectBond ODS-HD HPLC-column 5 μm 250 × 3.0 mm with a pre-column cartridge PerfectBond ODS-HD 5 μm 10 × 3.0 mm, double source of ionization for LCMS-2020 (electrospray (ESI) and chemical (APCI)) and software LabSol LCMS V5 LCMS2020 systempack were used. The low limit of the quantitative determination for HCTZ and CDS made up 10 ng/ml. m/z for CDS 441.20—positive scan, m/z for HCTZ 295.90—negative scan. The method has been applied to a pharmacokinetic study of 12.5 mg HCTZ and 16 mg CDS tablet in healthy volunteers.
文摘A validated ultra-performance liquid chromatography mass spectrometric method （UPLC-MS/MS） was used for the simultaneous quantitation of candesartan （CN） and hydrochlorothiazide （HCT） in human plasma. The analysis was performed on UPLC-MS/MS system using turbo ion spray interface. Negative ions were measured in multiple reaction monitoring （MRM） mode. The analytes were extracted using a liquid-liquid extraction （LLE） method by using 0.1 mL of plasma volume. The lower limit of quantitation for CN and HCT was 1.00 ng/mL whereas the upper limit of quantitation was 499.15 ng/mL and 601.61 ng/mL for CN and HCT respectively. CN d4 and HCT-13Cd2 were used as the internal standards for CN and HCT respectively. The chromatography was achieved within 2.0 min run time using a C18 Pheno-menex, Gemini NX （100 mm ~ 4.6 mm, 5 mm） column with organic mixture：buffer solution （80：20, v/v） at a flow rate of 0.800 mL/min. The method has been successfully applied to establish the bioequivalence of candesartan cilexetil （CNC） and HCT immediate release tablets with reference product in human subjects.
