Quantification of SHR0302 in human plasma by UPLC-MS/MS and application to a pharmacokinetic study.

SHR0302, as a novel Janus kinase (JAK) inhibitor 1, is used for treatment of rheumatoid arthritis (RA) in humans. A novel and sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed and validated for determining the concentration of SHR0302 in human plasma. A precipitation deproteinization method was used for plasma pretreatment with methanol. Detection was carried out on an Agilent 1,260 UPLC coupled with a Triple Quad 4000 mass spectrometer operated in positive multiple reaction monitoring mode, and the analytes were separated on a Synergi Polar-RP C18 (50 × 2.0 mm, 4 µm, Phenomenex) analytical column with gradient elution of 0.1% formic acid, and 2 mmol/l ammonium acetate in water and 0.1% formic acid and 2 mmol/l ammonium acetate in methanol, The selected ion transitions were m/z 415.2 → 258.2 and m/z 398.2 → 258.2 for SHR0302 and SHR143181 (internal standard), respectively. A full validation, including selectivity, linearity, carryover, precision, accuracy, recovery, matrix effect, dilution integrity and stability, was carried out in human plasma. It was successfully applied to a pharmacokinetic study in Chinese healthy subjects after oral administration of SHR0302 tablet.

Application of liquid chromatographic/tandem mass spectrometric method to a urinary excretion study of subutinib and active metabolite in human urine.

A novel and selective liquid chromatographic-mass spectrometric method (LC-MS/MS) has been established and validated for simultaneous determination of subutinib and active metabolite in human urine. Urine samples were extracted by liquid-liquid extraction with ethyl acetate and separated on a Wondasil C18 (150 × 2.1 mm, 3.5 µm), with methanol-0.2% formic acid solution (73:27, v/v) as mobile phase at flow rate of 0.2 mL/min. The linear range was 0.5000-200.0 ng/mL for subutinib and active metabolite, with a lower limit of quantitation of 0.5000 ng/mL. Intra- and inter-run precisions were all <11.8 and 14.3%, and the accuracies were all <4.5 and 5.4%, with the extraction recoveries 88.8-97.5 and 93.8-99.4% for the two analytes, respectively. The carryover values were all <15% for the two anayltes. The method was successfully applied to study urinary excretion of subutinib and active metabolite in human after oral administration of subutinib maleate capsules in fed and fasting states.

Simultaneous determination of subutinib and its active metabolite in human plasma by LC-MS/MS: Application to pharmacokinetic study.

A selective liquid chromatographic-mass spectrometric method (LC-MS/MS) has been established and validated for simultaneous determination of subutinib and its active metabolite in human plasma. Plasma samples were extracted by liquid-liquid extraction with ethyl acetate and separated on a Wondasil C18 (150mm×2.1mm, 3.5µm), with methanol-0.2% formic acid solution (73:27, v/v) as mobile phase at flow rate of 0.2ml/min. The linear range was 0.25-100ng/mL for subutinib and 0.125-50.0ng/mL for its active metabolite, with lower limit of quantitation of 0.25ng/mL and 0.125ng/mL, respectively. Intra- and inter-run precision were within 7.0 and 13.1%, and the accuracies (relative errors) were<7.0 and 8.0%, with the extraction recoveries 97.0-101.2% and 93.0-98.1% for the two analytes, respectively. The validated method was successfully applied to a pharmacokinetic study of subutinib and its active metabolite in human after oral administration of subutinib maleate capsules.

Effect of food on the pharmacokinetics of triflusal and its major active metabolite, 2-hydroxy-4-trifluoromethyl benzoic acid, in healthy subjects.

OBJECTIVE: The objective of this study was to evaluate the pharmacokinetic parameters of triflusal and its major active metabolite, 2-hydroxy-4-trifluoromethyl benzoic acid (HTB), following a single oral dose of 900 mg in healthy subjects under fed and fasting conditions. METHODS: The study participants (n=12) were randomized to receive one 900 mg triflusal capsule in a fasting condition (no food for 12 hours) or a fed condition (after a high-fat meal); after a 2-week washout period, participants received the same dose of triflusal capsule under the converse condition. Pharmacokinetic parameters were calculated using WinNonlin 6.2 software. Safety was evaluated through assessment of adverse events, standard laboratory evaluations, vital signs, and 12-lead electrocardiography. RESULTS: The mean Cmax of triflusal and HTB were 13.96, 110.2 ug/mL for the fasting state and 9.546, 97.15 ug/mL for the fed state, respectively. The AUC0-144 of triflusal and HTB were 19.66, 5,572 hxµg/mL for the fasting state and 22.20, 5,038 hxµg/mL for the fed state, the AUC0-∞ of triflusal and HTB were 19.79, 6,333 hxµg/mL for the fasting state and 22.44, 5,632 hxµg/mL for the fed state, respectively. The results showed that Cmax and AUCs for triflusal were outside the bioequivalency (BE) interval after food intake, but there was no statistically significant change for HTB. CONCLUSION: High-fat food intake may affect the pharmacokinetics of triflusal capsule in healthy subjects.

Effect of food on the single-dose pharmacokinetics and tolerability of clinofibrate tablets in Chinese healthy volunteers.

The aim of this study is to investigate a food effect on the single-dose pharmacokinetics and tolerability of clinofibrate tablets in 12 Chinese healthy volunteers. The authors evaluated the effect of being under a fasting or fed state at the time of drug intake on the single-dose of clinofibrate 400 mg tablets in a randomized, balanced, single-dose, two-treatment (fed and fasting), two-period, two-sequence study design with a 7-day washout period. The end points were the maximum plasma drug concentration (Cmax) and areas under the plasma-concentration curve (AUC) for 72 hours exposure (AUC0-72) and total exposure (AUC0-∞). All participants completed the whole study without side effects being observed. The Cmax mean of clinofibrate glucuronides and parent clinofibrate were 21.91, 17.85 µ/ml for the fasting state and 13.14, 11.25 µ/ml for the fed state, respectively. The AUC0-72 and AUC0-∞ of clinofibrate glucuronides and parent clinofibrate were 381.60, 307.07 µ/ ml and 404.55, 342.24 µ/ml for the fasting state and 379.02, 321.14 µ/ml and 432.24, 351.80 µ/ml for the fed state. The authors showed that food intake was associated with a significant decrease in Cmax, but no significant change in AUC values.

The effect of staggered administration of zinc sulfate on the pharmacokinetics of oral cephalexin.

AIMS: To investigate the effect of zinc sulfate on pharmacokinetics of cephalexin when administered concurrently or at strategically spaced dosing times designed to avoid the potential interaction in healthy volunteers. METHODS: In this study, all subjects (n= 12) were randomized to receive the following four treatments, separated by a wash-out period of 7 days: cephalexin 500mg alone, concomitantly with zinc 250mg, 3h after zinc 250mg or 3h before zinc 250mg. RESULTS: All subjects completed the study safely. Zinc supplements administered concurrently with cephalexin significantly decreased the peak serum concentration (C(max) ), area under the plasma concentration-time curve from zero to infinity (AUC(0-∞) ) and the time for which the plasma concentration of the drug remained above the minimal inhibitory concentration of the pathogenic organism (T > MIC) of cephalexin [mean percentage decrease (95% confidence intervals) of 31.05% (22.09-40.01%), 27.40% (18.33-36.47%) and 22.33% (12.51-32.16%), respectively; P < 0.05] compared with administration of cephalexin alone. Also, administration of zinc 3h before cephalexin decreased the C(max) , AUC(0-∞) and T > MIC of the drug compared with administration of cephalexin alone [mean percentage decrease (95% confidence intervals) of 11.48% (3.40-19.55%), 18.12% (9.63-26.60%) and 23.75% (14.30-33.20%), respectively; P < 0.05]. In contrast, the pharmacokinetics of cephalexin was not notably altered by administration of zinc 3h after cephalexin dosing (P > 0.05). CONCLUSIONS: The significant interaction between zinc and cephalexin might affect the clinical outcome of cephalexin therapy. The dosing recommendation is that zinc sulfate can be safely administered 3h after a cephalexin dose.

Determination of azatadine in human plasma by liquid chromatography/tandem mass spectrometry.

A sensitive method using liquid chromatography with tandem mass spectrometric detection (LC-MS/MS) was developed and validated for the analysis of antihistamine drug azatadine in human plasma. Loratadine was used as internal standard (IS). Analytes were extracted from human plasma by liquid/liquid extraction using ethyl acetate. The organic phase was reduced to dryness under a stream of nitrogen at 30 °C and the residue was reconstituted with the mobile phase. 5 µL of the resulting solution was injected onto the LC-MS/MS system. A 4.6 mm × 150 mm, I.D. 5 µm, Agilent TC-C(18) column was used to perform the chromatographic analysis. The mobile phase consisted of ammonium formate buffer 0.010 M (adjusted to pH 4.3 with 1M formic acid)/acetonitrile (20:80, v/v) The chromatographic run time was 5 min per injection and flow rate was 0.6 mL/min. The retention time was 2.4 and 4.4 min for azatadine and IS, respectively. The tandem mass spectrometric detection mode was achieved with electrospray ionization (ESI) iron source and the multiple reaction monitoring (MRM) (291.3 → 248.2m/z for azatadine, 383.3 → 337.3m/z for IS) was operated in positive ion modes. The low limit of quantitation (LLOQ) was 0.05 ng/mL. The intra-day and inter-day precision of the quality control (QC) samples was 8.93-11.57% relative standard deviation (RSD). The inter-day accuracy of the QC samples was 96.83-105.07% of the nominal values.