Determinations of mifepristone and its metabolites and their pharmacokinetics in healthy female Chinese subjects.

The aim of this study is to establish an HPLC method for simultaneous determinations of mifepristone and its metabolites, mono-demethylated mifepristone, di-demethylated mifepristone and C-hydroxylated mifepristone in plasma and to evaluate the pharmacokinetic characteristics of mifepristone tablet. Twenty healthy female Chinese subjects were recruited and a series of blood samples were collected before and after 0.25, 0.5, 1.0, 1.5, 2.0, 4.0, 8.0, 12.0, 24.0, 48.0, 72.0 and 96.0 hours administration by a single oral dose of 75 mg mifepristone tablet. Mifepristone and its three metabolites were extracted from plasma using ethyl acetate and determined by high performance liquid chromatography. The main pharmacokinetic parameters of mifepristone and its metabolites, including Cmax, tmax, MRT, t(1/2), V, CL, AUC(0-96 h) and AUC(0-infinity), were calculated by Drug and Statistical Software Version 2.0. The simple, accurate and stable method allows the sensitive determinations of mifepristone and its metabolites in human plasma up to 4 days after oral administration of 75 mg mifepristone tablet and the clinical applications of their pharmacokinetic studies.

Bioequivalence of nifedipine softgel and capsule in healthy Chinese volunteers by liquid chromatography-mass spectrometry.

The study aimed to compare and evaluate the bioequivalence of Calcigard-10 softgel and Adalat 10 capsule in healthy Chinese volunteers in a randomized, two-way cross over study design with a washout period of 7 days. A sensitive and reproducible electro-spray ionization liquid chromatography-mass spectrometry (ESI-LCMS) assay was developed and validated to determine nifedipine in human plasma using nitrendipine as internal standard. Nifedipine and nitrendipine were extracted from plasma using liquid-liquid extraction with methylene chloride as extraction solvent. The separation was performed by a Diamonsil ODS column (150 x 4.6 mm, 5 microm). The mobile phase was consisted of acetonitrile-5 mM ammonium acetate (52:48, v/v), delivered at flow rate of 1 mL/min. The 90% confidence intervals for the ratio values of logarithmic transformed Cmax and AUC were calculated to evaluate the bioequivalence of two preparations. The values of Cmax (92.3-112.7%), AUC0-t (84.5-95.1%) and AUC0-inf (84.4-95.5%) are within the interval criterion of 70-143% for Cmax and 80-125% for AUC. The Calcigard-10 softgel and Adalat 10 capsule are bioequivalent.

Determination of bergenin in human plasma after oral administration by HPLC-MS/MS method and its pharmacokinetic study.

A highly sensitive, simple and selective high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed and applied to the determination of bergenin concentration in human plasma. Bergenin and the internal standard (IS) thiamphenicol in plasma were extracted with ethyl acetate, separated on a C(18 )reversed-phase column, eluted with mobile phase of acetonitrile-water, ionized by negative ion pneumatically assisted electrospray and detected in the multi-reaction monitoring mode using precursor --> product ions of m/z 327.1 --> 192 for bergenin and 354 --> 185.1 for the IS, respectively. The linear range of the calibration curve for bergenin was 0.25-60 ng mL(-1), with the lowest limit of quantification of 0.25 ng mL(-1), and the intra/inter-day relative standard deviation (RSD) was less than 10%. The method is suitable for the determination of low bergenin concentration in human plasma after therapeutic oral doses, and has been first and successfully used for its pharmacokinetic studies in healthy Chinese volunteers.

[Determination of curcumol in plasma by HPLC-MS/MS method and its pharmacokinetics in Beagle dogs].

To establish a high performance liquid chromatography (HPLC) coupled with tandem mass spectrometry quantitative detection method for the determination of curcumol, the main ingredient of zedoary turmeric oil fat emulsion, and investigate its pharmacokinetics in Beagle dogs, nine healthy Beagle dogs were divided into three groups, and blood samples were collected at scheduled time points after intravenous injection of 7.5, 10 and 12.5 mg x kg(-1) zedoary turmeric oil fat emulsion. The concentrations of curcumol were determined and pharmacokinetics was calculated. A good linearity was obtained from 0.25 to 100 ng x mL(-1) in plasma. The relative recoveries were from 91.33% to 103.17%, and the absolute recoveries were from 31.61% to 37.20%. The intra-day and inter-day variances (RSD) were < 15%. The main pharmacokinetic parameters of curcumol after intravenous injection of 7.5, 10 and 12.5 mg x kg(-1) zedoary turmeric oil fat emulsion were as follows, T1/2 : (2.0 +/- 0.4), (1.7 +/- 0.2) and (2.3 +/- 0.8) h, AUC(0-infinity): (15.1 +/- 2.7), (18.3 +/- 2.0) and (29.5 +/- 4.0) ng x mL(-1) x h; MRT: (0.9 +/- 0.1), (0.8 +/- 0.2) and (0.8 +/- 0.1) h, CL: (21.9 +/- 4.0), (24.9 +/- 6.0) and (18.4 +/- 1.2) L x h(-1) x kg; Vd : (65.4 +/- 26.5), (62.0 +/- 13.4) and (61.2 +/- 19.8) L x kg(-1), respectively. The developed method was rapid, highly sensitive and specific and could be used in curcumol pharmacokinetic studies in vivo. A three-compartment model was best fit to the plasma concentration--time curves obtained in Beagle dogs and the plasma AUC was increased proportionally with doses.

[Pharmacokinetics and biodistribution of 3H-norcantharidin in mice].

A single dose of 3H-norcantharidin solution was intragastrically given, blood, tissues, urine and feces were collected as scheduled, and radioactivity in these samples was determined by tritium tracing method to investigate the pharmacokinetics, tissue distribution and excretion of norcantharidin in Kunming mice. The pharmacokinetic characteristics of norcantharidin were evaluated by DAS version 2.0. The blood concentration reached to maximum 0. 5 h after intragastric administration. The radioactivity in tissues was high in small intestine, gallbladder, stomach, adrenal gland, kidney, heart and uterus 15 minutes after administration, descending with time, and high in gallbladder, adrenal gland and uterus 3 hours post dosing. The 24 h accumulative excretion ratio of urine and feces were 65.40% and 1.33% respectively. 3H-norcantharidin was easily absorbed after orally given to mice, the radioactivity was high and existed for a long-time in gallbladder, adrenal gland and uterus, and low but also existed for a long-time in large intestine, thymus and fat tissue. 3H-norcantharidin was declined quickly in small intestine, stomach, kidney and heart, and occurred rarely in brain. Norcantharidin was excreted mainly by urinary route and seldom in feces, which may be the cause of the urinary stimulation side effects observed. Because the radioactivity measured were the sum of 3H labeled norcantharidin and its metabolites, further studies on the disposition of norcantharidin in mammal animals, on the separation or identification of metabolites and, if any, on their activities, are fairly needed.

Determination and pharmacokinetic study of norcantharidin in human serum by HPLC-MS/MS method.

A sensitive, simple and selective high-performance liquid chromatography-tandem mass spectrometry method was developed and applied to the determination of norcantharidin concentration in human serum. Norcantharidin (NCTD) and cyclophosphamide (IS) in serum were extracted with acetone, separated on a C18 reversed-phase column, gradiently eluted with a mobile phase of acetonitrile-water containing 2 mm ammonium acetate and 0.1% formic acid (pH 3), ionized by positive ion pneumatically assisted electrospray and detected in the multi-reaction monitoring mode using precursor-->product ions of m/z 169.3-->123.1 for NCTD and 261.2-->140.2 for IS, respectively. The linear range of the calibration curve for NCTD was 2.5-50 ng/mL, with a lowest limit of quantification of 2.5 ng/mL, and the intra/inter-day RSD was less than 10%. The method was suitable for determination of low NCTD concentration in human serum after therapeutic oral doses, and has been successfully used for pharmacokinetic studies in healthy Chinese volunteers.

Determination of sodium cromoglycate in human plasma by liquid chromatography with tandem mass.

A sensitive and selective liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed and validated for the determination of sodium cromoglycate (SCG) in human plasma after a nasal dose of 10.4 mg sodium cromoglycate nasal spray, using pravastatin sodium as the internal standard. The method was validated over a linear range of 0.300-20.0 ng/mL. SCG and I.S. were extracted from 1.0 mL of heparinized plasma by C(18) solid-phase extraction cartridges using methanol as eluting solvent. The dried residue was reconstituted with 100 microL of mobile phase, and 10 microL was injected onto the LC-MS/MS system. Chromatographic separation was achieved on a C(18) column (250 x 4.6 mm i.d., 5 microm particle size) with a mobile phase of methanol-acetonitrile-water (containing 2 mmol/L ammonium acetate; 42.5:42.5:15, v/v/v) at a flow rate of 0.4 mL/min. The analytes were detected with a triple quad LC-MS/MS using ESI with positive ionization. Ions monitored in the multiple reaction monitoring mode were m/z 469.0 (precursor ion) to m/z 245.0 (product ion) for SCG and m/z 447.2 (precursor ion) to m/z327.1 (product ion) for pravastatin sodium (internal standard) The average recovery of SCG from human plasma was 94.88% and the lower limit of quantitation was 0.3 ng/mL. Results from a 3-day validation study demonstrated excellent precision and accuracy across the calibration range of 0.3-20 ng/mL. The method was successfully applied to the pharmacokinetic study of SCG in healthy Chinese volunteers.