ABSTRACT
A sensitive and simple high-performance liquid chromatographic tandem mass spectrometric (LC-MS/MS) method for the determination of verapamil and norverapamil in human plasma was established and utilized in a pharmacokinetic study in healthy patients. Protein was precipitated by methanol in plasma samples, and the analytes and internal standard were separated on an Agilent Zorbax Eclipse C18 column (50 mm×4.6 mm, 5 μm) with a gradient procedure using methanol-acetonitrile (50∶50) as the organic phase and 0.1% formic acid - 5% acetonitrile - 10 mmol·L-1 ammonium formate solution as the mobile phase at flow rate of 0.5 mL·min-1. Electrospray ionization (ESI) and multiple reaction monitoring (MRM) detection modes were used for quantitative detection of verapamil, norverapamil and verapamil-d6 (IS). In the mode of multiple reaction monitoring of positive-ions, the monitoring ion pairs of verapamil, norverapamil and the verapamil-d6 were m/z 445.0→165.2, m/z 441.0→165.2 and m/z 461.1→165.2, respectively. The quantitative lower limit (LLOQ) for the determination of verapamil and norverapamil concentrations in human plasma can reach 0.1 ng·mL-1 in this assay. The calibration curve concentration ranged from 0.1 to 50 ng·mL-1 with high linearity (r2 > 0.997). The matrix effect of verapamil and norverapamil was 99.2%-100% and 101%-102%, respectively. The recovery of verapamil and norverapamil was 86.8%-95.9% and 87.4%-94.8%, respectively. This method has good specificity and high sensitivity. The determination of the verapamil and norverapamil was not subject to the matrix effect and stable extraction recovery was achieved in this assay. This method could be used to determine the concentration of verapamil and norverapamil in human plasma and suitable for human pharmacokinetic studies after approved by ethics committee.
ABSTRACT
A LC-MS/MS method for quantification of norfloxacin in human plasma had been developed. This method was applied to the pharmacokinetics study of norfloxacin in the human. The plasma sample was precipitated by methanol and ciprofloxacin was used as the internal standard (IS). Chromatographic separation was performed on a Symmetry® C18 column(100 mm×4.6 mm, 5 μm). Mobile phase contains 0.3% formic acid and 5% methanol in deionized water at a flow rate of 0.45 mL·min-1. Norfloxacin and ciprofloxacin (IS) were ionized with an ESI source and operated in positive ion mode. The detected ions were m/z 320.3→302.1 (norfloxacin), m/z 332.3→314.1 (ciprofloxacin). This LC-MS/MS method yielded a linearity over the range of 10-1 000 ng·mL-1 with the lower limit of quantitation (LLOQ) of 10 ng·mL-1. The intra and inter-assay precisions (RSD%) were within the range of 2.64%-7.23% and the accuracy (RE%) was less than ±5.00%. The pharmacokinetic parameters tmax, Cmax, AUC0-t, and t1/2 were 1.28±0.364 h, 627±171 ng·mL-1, 2 938±850 h·ng·mL-1, and 6.01±1.36 h, respectively. This LC-MS /MS method was proven simple, sensitive, rapid and suitable for pharmacokinetics study of norfloxacin in the human and Approved by the Medical Ethics Committee of Liuzhou Workers' Hospital.
ABSTRACT
A sensitive and efficient liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for quantitative determination of diflucortolone in rabbit plasma after dermal administration of diflucortolone valerate cream to rabbits. After extraction with ethyl acetate, the chromatographic separation was performed on Zorbax Eclipse XDB-C18 (50 mm×4.6 mm, 5 μm) with a gradient mobile phase consisting of 50% acetonitrile-50% methanol and 0.1% formic acid-5% methanol-5 mmol·L-1 ammonium formate at a flow rate of 0.35 mL·min-1. The quantitative analysis was carried out using multiple reaction monitoring (MRM) at specific ion transitions of m/z [M+H]+ 395.2→m/z 355.2 for diflucortolone and m/z [M+H]+ 258.1→m/z 120.9 for ethoxyphenylethylamine (internal standard) in positive ion mode with electrospray ionization (ESI) source. This validated LC-MS/MS method had a linearity over the concentration range of 0.01-10 ng·mL-1 with the lower limit of quantification (LLOQ) at 0.01 ng·mL-1. At level of LLOQ, the inter and intra-assay precision (RSD) were no greater than 9.82% and 11.0%, respectively. The main pharmacokinetic parameters of the diflucortolone including tmax, Cmax, AUC0-72 h, and t1/2 were as follows: (6.33±1.21) h, (0.168±0.080 0) ng·mL-1, (3.15±0.834) h·ng·mL-1, (32.0±17.4) h. The method was validated in the pharmacokinetic study of diflucortolone in rabbit following dermal administration of diflucortolone valerate cream at dose of 0.01 g·cm-2. In this study, the program of animal testing had been approved by Committee on the management and usage of experimental animal in the Evaluation Company of Innovative Drug, Tianjin Institute of Pharmaceutical Research.
ABSTRACT
A simple and sensitive method was developed for quantitation of obeticholic acid in rat plasma with liquid chromatography-tandem mass spectrometry (LC-MS/MS). After liquid-liquid extraction by methyl tert-butyl ether, the chromatographic separation was carried out on an ACE Excel 2 Super C18 column (50 mm×2.1 mm ID, 1.7 μm) with a gradient mobile phase consisting of acetonitrile and 2 mmol·L-1 ammonium formate at a flow rate of 0.2 mL·min-1. The quantitation analysis was performed using multiple reaction monitoring (MRM) at the specific ion transitions of m/z 418.9[M-H]-→401.2 for obeticholic acid and m/z 469.0[M-H]-→ 425.2 for glycyrrhetinic acid (internal standard) in the negative ion mode with electrospray ionization (ESI) source. This validated LC-MS/MS method yielded a good linearity over the range of 5 -5 000 ng·mL-1 with the lower limit of quantitation (LLOQ) of 5 ng·mL-1. The intra and inter-assay precisions (RSD) were all less than 9.82% and the accuracy (RE) was within ±6.90%. The extraction recovery of obeticholic acid was from 85.4% to 88.5%, and the matrix effect of obeticholic acid ranged from 78.9% to 82.5%. Stability test suggest that obeticholic acid in rat plasma was stable for 24 h on workbench, up to 1 month at -70℃, and after three cycles of freeze-thaw. Extracted samples were stable for more than 24 h in an auto-sampler at 6℃. The precision was less than 7.25%, and the accuracy was within ±11.2%, after being diluted 10 times by blank rat plasma. The method has been successfully applied to a pharmacokinetic study of obeticholic acid in rats following oral administration at the dose of 2.5 mg·kg-1.
ABSTRACT
A pre-column derivatization method combined with UHPLC-MS/MS was developed for the simultaneous determination of salidroside and tyrosol in Beagle dog plasma. After protein precipitation by acetonitrile, the liquid supernatant was treated with dansyl chloride under dark conditions at 60℃ for 30 min, and then, the sample solution was extracted using methyl tertiary butyl ether. The multiple reaction monitoring in positive ion mode was used for MS detection of the tested analytes with the specific ion transitions of m/z 534.2→372.0 for salidroside derivative, m/z 372.0→171.0 for tyrosol derivative and m/z 506.0→171.0 for arbutin derivative. The chromatograph separation was achieved on an ACQUITY UPLC® BEH C18 column (100 mm×2.1 mm, 1.7 μm) with a gradient mobile phase consisting of acetonitrile (0.1% formic acid)-water (10% acetonitrile, 0.1% formic acid) for 9 min. The assay showed a good linearity over the range of 0.02/0.1-20/10 μmol·L-1 with a lower limit of quantitation of 0.02 and 0.1 μmol·L-1 for salidroside and tyrosol in dog plasma, respectively. The intra-and inter-day precisions were all less than 8.68%, and the accuracy was within ±11.4%. The established method with a high sensitivity, good specificity and reliability was appropriate for simultaneous determination of salidroside and tyrosol in dog plasma and successfully applied to a pharmacokinetic study after intragastric administration of salidroside to Beagle dogs.
ABSTRACT
Bentysrepinine (Y101), a derivative of phenyalanine dipeptide, has a novel mechanism in the treatment of hepatitis B virus (HBV) infection with a good anti-HBV effect. In the present study, a fluorometric-based high throughput method using cytochrome P450 (CYP) screening kit was adopted to evaluate in vitro inhibition potential of Y101 on CYP isoenzymes by calculating remaining enzyme activities and inhibitory potential (IC50 values) using the determined values of fluorescence intensity. The result showed that Y101 exhibited little activity in the inhibition of CYP1A2, CYP3A4, CYP2C9, CYP2C19 and CYP2D6 (IC50 > 100 μmol·L-1). Y101 was used to treat human primary hepotocytes for 72 h, and the enzyme activities of CYP1A2, CYP2B6 and CYP3A4 were determined with a cocktail of probe substrates for the three CYP isoforms. The metabolites were simultaneously determined using a LC-MS/MS method. Y101 had no activity in the induction of CYP1A2, CYP2B6 and CYP3A4 on the basis of the following results:① The ratio of enzyme activities between test and control groups were all below than 1 (varied from 0.662 to 0.928); ② The induction potential of Y101 were lower than forty percent compared with that of positive groups. The above results suggest that Y101 has little activity in the regulation of metabolic drug-drug interactions based on the CYP isoform changes following co-administration of drugs.
ABSTRACT
Bentysrepinine (Y101), a derivative of phenylalanine dipeptide, is a novel drug candidate for the treatment of hepatitis B virus (HBV) infection. Our previous preclinical pharmacokinetic study showed that its in vivo absorption and distribution characteristics were probably related to transmembrane transport after Y101 was administered intragastically in rats. In this study, Caco-2 and MDCK-MDR1 cell models were used to investigate interactions between Y101 and P-gp through the apparent permeation coefficient (Papp) and efflux ratio (RE); the results showed that Y101 was a substrate of P-gp. In addition, gene-transfected cell models, HEK293-hOATP1B1, HEK293-hOATP2B1 and CHO-PEPT1 were used to evaluate the affinity to OATP1B1,
ABSTRACT
A rapid, sensitive and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of clevidipine butyrate and its primary metabolite clevidipine acid in dog blood. After one-step protein precipitation with methanol, the chromatographic separation was carried out on an Ecosil C18 column (150 mm x 4.6 mm, 5 µm) with a gradient mobile phase consisting of methanol and 5 mmol · L(-1) ammonium formate. A chromatographic total run time of 13.0 min was achieved. The quantitation analysis was performed using multiple reaction monitoring (MRM) at the specific ion transitions of m/z 454.1 [M-H]- --> m/z 234.1 for clevidipine butyrate, m/z 354.0 [M-H]- --> m/z 208.0 for clevidipine acid and m/z 256.1 [M-H]- --> m/z 227.1 for elofesalamide (internal standard, IS) in the negative ion mode with electrospray ionization (ESI) source. The linear calibration curves for clevidipine butyrate and clevidipine acid were obtained in the concentration ranges of 0.5-100 ng · mL and 1-200 ng · mL(-1), separately. The lower limit of quantification of clevidipine butyrate and clevidipine acid were 0.5 ng · mL(-1) and 1 ng · mL(-1). The intra and inter-assay precisions were all below 12.9%, the accuracies were all in standard ranges. Stability testing indicated that clevidipine butyrate and clevidipine acid in dog blood with the addition of denaturant methanol was stable under various processing and/or handling conditions. The validated method has been successfully applied to a pharmacokinetic study of clevidipine butyrate injection to 8 healthy Beagle dogs following intravenous infusion at a flow rate of 5 mg · h(-1) for 0.5 h.
Subject(s)
Animals , Dogs , Butyrates , Blood , Pharmacokinetics , Calibration , Chromatography, Liquid , Infusions, Intravenous , Pyridines , Blood , Pharmacokinetics , Tandem Mass SpectrometryABSTRACT
A significant number of organic carboxylic acids have been shown to influence the absorption and distribution of drugs mediated by organic anion transporters (OATs). In this study, uptake experiments were performed to assess the inhibitory effects of cinnamic acid, ferulic acid, oleanolic acid, deoxycholic acid, and cynarin on hOAT1, hOAT3, hOATP1B1, and hOATP2B1. After a drug-drug interaction (DDI) investigation, cinnamic acid, ferulic acid, deoxycholic acid, and cynarin were found and validated to inhibit hOAT1 in a competitive manner, and deoxycholic acid was found to be an inhibitor of all four transporters. The apparent 50% inhibitory concentrations of cinnamic acid, ferulic acid, deoxycholic acid, and cynarin were estimated to be 133.87, 3.69, 90.03 and 6.03 μmol·L(-1) for hOAT1, respectively. The apparent 50% inhibitory concentrations of deoxycholic acid were estimated to be 9.57 μmol·L(-1) for hOAT3, 70.54 μmol·L(-1) for hOATP1B1, and 168.27 μmol·L(-1) for hOATP2B1. Because cinnamic acid, ferulic acid, and cynarin are ingredients of food or food additives, the present study suggests there are new food-drug interactions to be disclosed. In addition, deoxycholic acid may be used as a probe for studying the correlation of OATs and OATPs.
Subject(s)
Humans , Carboxylic Acids , Pharmacology , Cinnamates , Pharmacology , Coumaric Acids , Pharmacology , Deoxycholic Acid , Pharmacology , Diet , Drug Interactions , HEK293 Cells , Organic Anion Transport Protein 1 , Organic Anion Transporters , Plant Extracts , Pharmacology , Plants, Medicinal , ChemistryABSTRACT
The paper is to report the development of a high-performance liquid chromatographic/tandem mass spectrometry (HPLC-MS/MS) method for the determination of icaritin (ICT) in rat plasma. After precipitated with acetonitrile from the plasma, ICT was isolated chromatographically on a Dikma C18 column. The mobile phase consisted of acetonitrile-water-acetic acid (72 : 28 : 1.5, v/v/v). Electrospray ionization (ESI) source was applied and operated in the positive ion mode. Multiple reaction monitoring (MRM) mode with the transitions of m/z 387 --> m/z 313 and m/z 331 --> m/z 315 were used to quantify ICT and the internal standard, respectively. The linear calibration curve was obtained in the concentration range of 2.5-1,000 ng x mL(-1). The lower limit of quantification was 2.5 ng x mL(-1). The inter- and intra-day precision (RSD) were less than 9.63%, and the accuracy (relative error) was within +/-7.42%. The method was proved to be suitable for the pharmacokinetics of ICT, which offers advantages of high sensitivity and selectivity.
Subject(s)
Animals , Female , Male , Rats , Administration, Oral , Chromatography, High Pressure Liquid , Methods , Epimedium , Chemistry , Flavonoids , Blood , Pharmacokinetics , Plants, Medicinal , Chemistry , Rats, Wistar , Reproducibility of Results , Sensitivity and Specificity , Spectrometry, Mass, Electrospray Ionization , Methods , Tandem Mass Spectrometry , MethodsABSTRACT
To develop and validate a liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the determination of tamsulosin in dog plasma after oral administration of controlled-release tablet of tamsulosin hydrochloride, the samples and the internal standard, diphenhydramine, were extracted from dog plasma by n-hexane-dichloromethane (2 : 1), and separated on a Bonchrom XBP-C18 column using a mobile phase consisted of methanol-acetonitrile-ammonium formate (10 mmol x L(-1)) (30 : 40 : 30, v/v/v), at a flow rate of 0.4 mL x min(-1). Mass spectrometric detection was operated on a triple quadrupole tandem mass spectrometer equipped with atmospheric pressure chemical ionization (APCI) source in positive mode. Quantification was performed using selected reaction monitoring (SRM) of the transitions m/z 409 --> 228 for tamsulosin and m/z 256 --> 167 for the internal standard, respectively. The linear concentration ranges of the calibration curves for tamsulosin were 0.02 - 50 ng x mL(-1). The lower limit of quantification was 0.02 ng x mL(-1). The accuracy ranged from -2.61% to 8.82% in terms of relative error (RE). The intra- and inter-day relative standard deviation (RSD) across three-run validations were lower than 9.72%. The method was proved to be highly sensitive, selective, and had been successfully applied to the pharmacokinetic study after an oral administration of 0.4 mg tamsulosin hydrochloride controlled release preparations to dogs.