A new method using high-performance liquid chromatography coupled with ultra violet detection(HPLC–UV)was developed and validated for the simultaneous quantification of atazanavir,dolutegravir,darunavir,efavirenz,etr...A new method using high-performance liquid chromatography coupled with ultra violet detection(HPLC–UV)was developed and validated for the simultaneous quantification of atazanavir,dolutegravir,darunavir,efavirenz,etravirine lopinavir,raltegravir,rilpivirine and tipranavir in human plasma.For the first time we reported here the development and validation of an HPLC–UV assay to quantify the frequently administered 9antiretroviral compounds including dolutegravir and rilpivirine.A simple solid phase extraction procedure was applied to 500 μL aliquots of plasma.The chromatographic separation of the drugs and internal standard(quinoxaline) was achieved with a gradient of acetonitrile and sodium acetate buffer on a C_(18) reverse-phase analytical column with a 25 min analytical run time.Calibration curves were optimised according to the therapeutic range of drug concentrations in patients,and the coefficient of determination(r^2) was higher than0.99 for all analytes.Mean intraday and interday precisions(RSD) for all compounds were less than 15.0%,and the mean accuracy(% deviation from nominal concentration) was also found to be less than 15.0%.Extraction recovery range was between 80% and 120% for all drugs analysed.The solid phase extraction and HPLC–UV method enable a specific,sensitive,and reliable simultaneous determination of nine antiretroviral agents in plasma.Good extraction efficiency and low limit of HPLC–UV quantification make this method suitable for use in clinical trials and therapeutic drug monitoring.展开更多
Nicotine and cotinine in hair are good biomarkers for assessing long-term exposure to smoking. However, analytical devices such as GC/MS are associated with high cost and are not widely used. HPLC/UV is used widely in...Nicotine and cotinine in hair are good biomarkers for assessing long-term exposure to smoking. However, analytical devices such as GC/MS are associated with high cost and are not widely used. HPLC/UV is used widely in laboratories, but is unsuitable for measurement of minor constituents, except when using the column-switching method. Thus, we aimed to establish a simple, inexpensive and sensitive method based on HPLC/UV with column switching for measuring nicotine and cotinine in hair. First, we compared the presence and absence of a column selection unit. We then measured amounts of nicotine and cotinine in hair samples collected from the general population, and compared both the corresponding levels and the detection limits with those in previous studies. Finally, initial and running costs of HPLC/UV were compared with other analytical methods. As one of the results, the areas of nicotine and cotinine measured by HPLC/UV with column-switching method were 12.9 and 16.9 times greater, respectively, than those without the column-switching method. The amount of nicotine and cotinine in hair was significantly correlated to number of cigarettes smoked per day (r = 0.228, p = 0.040). In addition, the HPLC/UV method showed similar sensitivity and detection limit (nicotine, 0.10 ng/mg;cotinine, 0.08 ng/mg) as reported in previous studies. The cost of the HPLC/UV method is lower than that of other analytical methods. We were able to establish a low-cost method with good sensitivity for measuring nicotine and cotinine in hair. The HPLC/UV with a column-switching method will be useful as a first step in screening surveys in order to better understand the effects of smoking exposure.展开更多
Two new selective, precise, and accurate methods were developed for the determination of fenofibrate in the presence of its basic degradation product. In the first method fenofibrate was determined using an algorithm ...Two new selective, precise, and accurate methods were developed for the determination of fenofibrate in the presence of its basic degradation product. In the first method fenofibrate was determined using an algorithm bivariate calibration derivative method, in which an optimum pair of wavelengths was chosen for the determination of different binary mixtures. In the second method (HPLC), separation was achieved on RESTEK Pinnacle II phenyl column (5 μm, 250 × 4.6 mm) and Pinnacle II phenyl (5 μm, 10 × 4 mm) guard cartridge using a mobile phase consisting of methanol –0.1% phosphoric acid (60:40, v/v) at a flow rate 2 mL●min–1, and the column oven temperature was set at 50°C. The UV detector was time programmed at 302 nm and 289 nm for the internal standard (I.S.) and fenofibrate, respectively. The proposed methods were successfully applied for the determination of fenofibrate and its degradation product in the laboratory-prepared mixture and in pharmaceutical formulation. The assay results obtained using the bivariate method were statistically compared to those of the HPLC method and good agreement was observed.展开更多
5-Fluorocytosine (5-FC) is used for the treatment of several infections. It is extremely important to monitor blood level concentration for maximum activity to avoid its side effects. A simple, faster, and more accura...5-Fluorocytosine (5-FC) is used for the treatment of several infections. It is extremely important to monitor blood level concentration for maximum activity to avoid its side effects. A simple, faster, and more accurate analytical method is developed and validated using high-performance liquid chromatography with UV detection in a very low-volume serum sample. Exactly 50 μL of serum was precipitated with 5% trichloroacetic acid. After mixing and centrifugation, 20 μL of supernatant was injected into the HPLC column. Detection was performed at 280 nm. The method is very specific and free from interfering substances due to different drugs and their different circulating metabolites. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.50 μg/L and 1.0 μg/L, respectively. The method was linear in the range of 5 - 150 μg/L in the serum sample. In method comparison, the correlation coefficient r<sup>2</sup> was 0.999 and the percentage recovery was 90% - 105% on four levels of the quality control samples. Within run and between run precision was found to be less than 2.2% at four different concentrations (5, 25, 50, and 100 μg/L). A simple, faster, and more accurate HPLC-UV method is developed which is very useful for monitoring 5-FC concentration in low volume serum samples without evaporation step and ion exchange chromatography within minutes.展开更多
基金supported by “Ministero della Salute” “Ricerca corrente 2015” grant to E.C.
文摘A new method using high-performance liquid chromatography coupled with ultra violet detection(HPLC–UV)was developed and validated for the simultaneous quantification of atazanavir,dolutegravir,darunavir,efavirenz,etravirine lopinavir,raltegravir,rilpivirine and tipranavir in human plasma.For the first time we reported here the development and validation of an HPLC–UV assay to quantify the frequently administered 9antiretroviral compounds including dolutegravir and rilpivirine.A simple solid phase extraction procedure was applied to 500 μL aliquots of plasma.The chromatographic separation of the drugs and internal standard(quinoxaline) was achieved with a gradient of acetonitrile and sodium acetate buffer on a C_(18) reverse-phase analytical column with a 25 min analytical run time.Calibration curves were optimised according to the therapeutic range of drug concentrations in patients,and the coefficient of determination(r^2) was higher than0.99 for all analytes.Mean intraday and interday precisions(RSD) for all compounds were less than 15.0%,and the mean accuracy(% deviation from nominal concentration) was also found to be less than 15.0%.Extraction recovery range was between 80% and 120% for all drugs analysed.The solid phase extraction and HPLC–UV method enable a specific,sensitive,and reliable simultaneous determination of nine antiretroviral agents in plasma.Good extraction efficiency and low limit of HPLC–UV quantification make this method suitable for use in clinical trials and therapeutic drug monitoring.
文摘Nicotine and cotinine in hair are good biomarkers for assessing long-term exposure to smoking. However, analytical devices such as GC/MS are associated with high cost and are not widely used. HPLC/UV is used widely in laboratories, but is unsuitable for measurement of minor constituents, except when using the column-switching method. Thus, we aimed to establish a simple, inexpensive and sensitive method based on HPLC/UV with column switching for measuring nicotine and cotinine in hair. First, we compared the presence and absence of a column selection unit. We then measured amounts of nicotine and cotinine in hair samples collected from the general population, and compared both the corresponding levels and the detection limits with those in previous studies. Finally, initial and running costs of HPLC/UV were compared with other analytical methods. As one of the results, the areas of nicotine and cotinine measured by HPLC/UV with column-switching method were 12.9 and 16.9 times greater, respectively, than those without the column-switching method. The amount of nicotine and cotinine in hair was significantly correlated to number of cigarettes smoked per day (r = 0.228, p = 0.040). In addition, the HPLC/UV method showed similar sensitivity and detection limit (nicotine, 0.10 ng/mg;cotinine, 0.08 ng/mg) as reported in previous studies. The cost of the HPLC/UV method is lower than that of other analytical methods. We were able to establish a low-cost method with good sensitivity for measuring nicotine and cotinine in hair. The HPLC/UV with a column-switching method will be useful as a first step in screening surveys in order to better understand the effects of smoking exposure.
文摘Two new selective, precise, and accurate methods were developed for the determination of fenofibrate in the presence of its basic degradation product. In the first method fenofibrate was determined using an algorithm bivariate calibration derivative method, in which an optimum pair of wavelengths was chosen for the determination of different binary mixtures. In the second method (HPLC), separation was achieved on RESTEK Pinnacle II phenyl column (5 μm, 250 × 4.6 mm) and Pinnacle II phenyl (5 μm, 10 × 4 mm) guard cartridge using a mobile phase consisting of methanol –0.1% phosphoric acid (60:40, v/v) at a flow rate 2 mL●min–1, and the column oven temperature was set at 50°C. The UV detector was time programmed at 302 nm and 289 nm for the internal standard (I.S.) and fenofibrate, respectively. The proposed methods were successfully applied for the determination of fenofibrate and its degradation product in the laboratory-prepared mixture and in pharmaceutical formulation. The assay results obtained using the bivariate method were statistically compared to those of the HPLC method and good agreement was observed.
文摘5-Fluorocytosine (5-FC) is used for the treatment of several infections. It is extremely important to monitor blood level concentration for maximum activity to avoid its side effects. A simple, faster, and more accurate analytical method is developed and validated using high-performance liquid chromatography with UV detection in a very low-volume serum sample. Exactly 50 μL of serum was precipitated with 5% trichloroacetic acid. After mixing and centrifugation, 20 μL of supernatant was injected into the HPLC column. Detection was performed at 280 nm. The method is very specific and free from interfering substances due to different drugs and their different circulating metabolites. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.50 μg/L and 1.0 μg/L, respectively. The method was linear in the range of 5 - 150 μg/L in the serum sample. In method comparison, the correlation coefficient r<sup>2</sup> was 0.999 and the percentage recovery was 90% - 105% on four levels of the quality control samples. Within run and between run precision was found to be less than 2.2% at four different concentrations (5, 25, 50, and 100 μg/L). A simple, faster, and more accurate HPLC-UV method is developed which is very useful for monitoring 5-FC concentration in low volume serum samples without evaporation step and ion exchange chromatography within minutes.
