Potential mutagenic impurities in Active Pharmaceutical Ingredient, Meropenem Trihydrate were assessed and a novel analytical method for their quantification was developed and validated. This Liquid Chromatographic me...Potential mutagenic impurities in Active Pharmaceutical Ingredient, Meropenem Trihydrate were assessed and a novel analytical method for their quantification was developed and validated. This Liquid Chromatographic method using High Resolution Mass Spectrometer (LC-HRMS) technique is proved to be suitable for simultaneous quantification of all ten identified impurities with required specificity, sensitivity, resolution, precision, accuracy, and other method characteristics as per ICH Guidelines. The acceptable limit of less than 2.9 μg/g was considered for evaluations, based on drug substance dosage and duration of treatment. The method stands most sensitive with a Limit of Detection of 0.35 μg/g, considering the challenge full acceptance criteria as per current regulatory standards.展开更多
A new trust region algorithm for solving convex LC 1 optimization problem is presented.It is proved that the algorithm is globally convergent and the rate of convergence is superlinear under some reasonable assum...A new trust region algorithm for solving convex LC 1 optimization problem is presented.It is proved that the algorithm is globally convergent and the rate of convergence is superlinear under some reasonable assumptions.展开更多
Instead of normally tackling electric circuits by virtue oI the Klrctllaott＇s theorem wnose aim is to uerlvc voxt^gc, electric current, and electric impedence, our aim in this paper is to derive the characteristic fr...Instead of normally tackling electric circuits by virtue oI the Klrctllaott＇s theorem wnose aim is to uerlvc voxt^gc, electric current, and electric impedence, our aim in this paper is to derive the characteristic frequency of a three-loop mesoscopic LC circuit with three mutual inductances, e.g., for the radiating frequency of the three-loop LC oscillator, we adopt the invariant eigen-operator （lEO） method to realize our aim.展开更多
In this paper we present a filter-trust-region algorithm for solving LC1 unconstrained optimization problems which uses the second Dini upper directional derivative. We establish the global convergence of the algorith...In this paper we present a filter-trust-region algorithm for solving LC1 unconstrained optimization problems which uses the second Dini upper directional derivative. We establish the global convergence of the algorithm under reasonable assumptions.展开更多
A liquid chromatography tandem mass spectrometry (LC-MS/MS) based method was developed for the simultaneous monitoring plasma levels of Sitagliptin (STG) and Pioglitazone (PIO) for applicability to pharmacokinetic stu...A liquid chromatography tandem mass spectrometry (LC-MS/MS) based method was developed for the simultaneous monitoring plasma levels of Sitagliptin (STG) and Pioglitazone (PIO) for applicability to pharmacokinetic studies. The method was based on HPLC separation on the reversed phase Phenomenex Synergy C18 column (30 mm length, 4.6 mm internal diameter, and 4.0 μm particle size) at a temperature of 40?C using a binary gradient mobile phase consisting of methanol and 2 mM ammonium acetate buffer pH adjusted to 4.5 with acetic acid, at a flow rate of 1 mL?min?1. Tolbutamide was used as an internal standard. Detection of analytes was achieved with LC-MS/MS system in Multiple Reaction Monitoring (MRM) mode. The method was validated over concentration range of 10.98 - 2091.77 ng?mL?1 for SIT and 8.25 - 1571.63 ng?mL?1 for PIO and lower limit of quantification was 10.98 ng?mL?1 and 8.25 ng?mL?1 for STG and PIO respectively. Recoveries from spiked controls were within acceptance criteria for all the analytes and internal standard at all QC levels. Within batch and between batch accuracy for STG was found within 96.9% - 100.3% and for PIO was found within 100.0% - 104.3%. Within batch and between batch precision for STG was less than 3.1% CV (coefficient of variation) and for PIO was less than 5.3% CV at all concentrations levels. This method was successfully applied to monitor pharmacokinetics profile of both STG and PIO on simultaneous oral administration to rats. This method can be applicable for pharmacokinetic drug-drug interaction studies.展开更多
The acute toxic effects of ammonium sulphate to fresh-water catfish, Heteropneustes fossilis (H.fossilis) have been studied by determining LC50 values with 95% confidence limits, by the graphic method, the logistic me...The acute toxic effects of ammonium sulphate to fresh-water catfish, Heteropneustes fossilis (H.fossilis) have been studied by determining LC50 values with 95% confidence limits, by the graphic method, the logistic method, the Spearman and Karber method and the trimmed Spearman-Karber method. The trimmed Spearman-Karber method was found the most ideal for ammonium salt toxicity test. The flaws in the trimmed Spearman-Karber method are also discussed.展开更多
文摘Potential mutagenic impurities in Active Pharmaceutical Ingredient, Meropenem Trihydrate were assessed and a novel analytical method for their quantification was developed and validated. This Liquid Chromatographic method using High Resolution Mass Spectrometer (LC-HRMS) technique is proved to be suitable for simultaneous quantification of all ten identified impurities with required specificity, sensitivity, resolution, precision, accuracy, and other method characteristics as per ICH Guidelines. The acceptable limit of less than 2.9 μg/g was considered for evaluations, based on drug substance dosage and duration of treatment. The method stands most sensitive with a Limit of Detection of 0.35 μg/g, considering the challenge full acceptance criteria as per current regulatory standards.
基金Supported by the National Natural Science Foundation of P.R.China(1 9971 0 0 2 ) and the Subject ofBeijing Educational Committ
文摘A new trust region algorithm for solving convex LC 1 optimization problem is presented.It is proved that the algorithm is globally convergent and the rate of convergence is superlinear under some reasonable assumptions.
基金Project supported by the National Natural Science Foundation of China(Grant No.11775208)
文摘Instead of normally tackling electric circuits by virtue oI the Klrctllaott＇s theorem wnose aim is to uerlvc voxt^gc, electric current, and electric impedence, our aim in this paper is to derive the characteristic frequency of a three-loop mesoscopic LC circuit with three mutual inductances, e.g., for the radiating frequency of the three-loop LC oscillator, we adopt the invariant eigen-operator （lEO） method to realize our aim.
基金Supported by CERG: CityU 101005 of the Government of Hong Kong SAR, Chinathe National Natural ScienceFoundation of China, the Specialized Research Fund of Doctoral Program of Higher Education of China (Grant No.20040319003)the Natural Science Fund of Jiangsu Province of China (Grant No. BK2006214)
文摘In this paper we present a filter-trust-region algorithm for solving LC1 unconstrained optimization problems which uses the second Dini upper directional derivative. We establish the global convergence of the algorithm under reasonable assumptions.
文摘A liquid chromatography tandem mass spectrometry (LC-MS/MS) based method was developed for the simultaneous monitoring plasma levels of Sitagliptin (STG) and Pioglitazone (PIO) for applicability to pharmacokinetic studies. The method was based on HPLC separation on the reversed phase Phenomenex Synergy C18 column (30 mm length, 4.6 mm internal diameter, and 4.0 μm particle size) at a temperature of 40?C using a binary gradient mobile phase consisting of methanol and 2 mM ammonium acetate buffer pH adjusted to 4.5 with acetic acid, at a flow rate of 1 mL?min?1. Tolbutamide was used as an internal standard. Detection of analytes was achieved with LC-MS/MS system in Multiple Reaction Monitoring (MRM) mode. The method was validated over concentration range of 10.98 - 2091.77 ng?mL?1 for SIT and 8.25 - 1571.63 ng?mL?1 for PIO and lower limit of quantification was 10.98 ng?mL?1 and 8.25 ng?mL?1 for STG and PIO respectively. Recoveries from spiked controls were within acceptance criteria for all the analytes and internal standard at all QC levels. Within batch and between batch accuracy for STG was found within 96.9% - 100.3% and for PIO was found within 100.0% - 104.3%. Within batch and between batch precision for STG was less than 3.1% CV (coefficient of variation) and for PIO was less than 5.3% CV at all concentrations levels. This method was successfully applied to monitor pharmacokinetics profile of both STG and PIO on simultaneous oral administration to rats. This method can be applicable for pharmacokinetic drug-drug interaction studies.
文摘The acute toxic effects of ammonium sulphate to fresh-water catfish, Heteropneustes fossilis (H.fossilis) have been studied by determining LC50 values with 95% confidence limits, by the graphic method, the logistic method, the Spearman and Karber method and the trimmed Spearman-Karber method. The trimmed Spearman-Karber method was found the most ideal for ammonium salt toxicity test. The flaws in the trimmed Spearman-Karber method are also discussed.
