Determination of lapatinib (GW572016) in human plasma by liquid chromatography electrospray tandem mass spectrometry (LC-ESI-MS/MS)

A sensitive method for the determination of lapatinib (GW572016) in human plasma was developed using high-performance liquid chromatographic separation with tandem mass spectrometric detection. Plasma samples (100 microL) were prepared using solid phase extraction (SPE) columns, and 6.0 microL of the reconstituted eluate was injected onto a Phenomenex CuroSil-PFP 3 mu analytical column (50 mm x 2.0mm) with an isocratic mobile phase. Analytes were detected with a PE SCIEX API-365 LC-MS/MS system at unit (Q1) and low (Q3) resolution in positive multiple reaction monitoring mode (m/z 581 (precursor ion) to m/z 364 (product ion) for lapatinib). The mean recovery for lapatinib was 75% with a lower limit of quantification of 15 ng/mL (S/N=11.3, CV< or =14%). This method was validated over a linear range of 100-10,000 ng/mL, and results from a 5-day validation study demonstrated good within-day and between-day precision and accuracy. This method has been used to measure plasma lapatinib concentrations in a Phase I study in children with cancer.     

Quantitative determination of erythromycylamine in human plasma by liquid chromatography-mass spectrometry and its application in a bioequivalence study of dirithromycin

A sensitive, rapid liquid chromatographic-electrospray ionization mass spectrometric method for determination of erythromycylamine in human plasma was developed and validated. Erythromycylamine in plasma (0.2 mL) was extracted with ethyl acetate, the organic phase was transferred to another clear 1.5 mL Eppendorf tube and evaporated to dryness under gentle nitrogen stream at 45 degrees C, and the residue was dissolved in 100 microL of mobile phase. The samples were separated using a Thermo Hypersil HyPURITY C18 reversed-phase column (150 mm x 2.1 mm I.D., 5 microm). A mobile phase containing 10 mM of ammonium acetate (pH = 6.4)-acetonitrile-methanol (50:10:40, v/v/v) was used isocratically eluting at a flow rate of 0.2 mL/min. Erythromycylamine and its internal standard (IS), midecamycin, were measured by electrospray ion source in positive selective ion monitoring mode. The method demonstrated that good linearity ranged from 4.5 to 720 ng/mL with r = 0.9997. The limit of quantification for erythromycylamine in plasma was 4.5 ng/mL with good accuracy and precision. The mean extraction recovery of the method was higher than 75.1% and 72.7% for erythromycylamine and IS, respectively. The intra-day and inter-day precision ranged from 5.2% to 6.4% and 5.6-9.3% (relative standard deviation, RSD), respectively. The established method has been successfully applied to a bioequivalence study of two dirithromycin formulations for 18 healthy volunteers.     

High-throughput determination of fudosteine in human plasma by liquid chromatography-tandem mass spectrometry, following protein precipitation in the 96-well plate format.

A 96-well protein precipitation, liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and fully validated for the determination of fudosteine in human plasma. After protein precipitation of the plasma samples (50 microL) by the methanol (150 microL) containing the internal standard (IS), erdosteine, the 96-well plate was vortexed for 5 min and centrifuged for 15 min. The 100 microL supernatant and 100 microL mobile phase were added to another plate and mixed and then the mixture was directly injected into the LC-MS/MS system in the negative ionization mode. The separation was performed on a XB-CN column for 3.0 min per sample using an eluent of methanol-water (60:40, v/v) containing 0.005% formic acid. Multiple reaction monitoring (MRM) using the precursor-product ion transitions m/z 178-->91 and m/z 284-->91 was performed to quantify fudosteine and erdosteine, respectively. The method was sensitive with a lower limit of quantification (LLOQ) of 0.02 microg mL(-1), with good linearity (r>0.999) over the linear range of 0.02-10 microg mL(-1). The within- and between-run precision was less than 5.5% and accuracy ranged from 94.2 to 106.7% for quality control (QC) samples at three concentrations of 0.05, 1 and 8 microg mL(-1). The method was employed in the clinical pharmacokinetic study of fudosteine formulation product after oral administration to healthy volunteers.     

Simultaneous quantification of voriconazole and posaconazole in human plasma by high-performance liquid chromatography with ultra-violet detection

A sensitive and selective high-performance liquid chromatographic (HPLC) method with ultra-violet detection has been developed and validated for the simultaneous determination of posaconazole and voriconazole, two systemic anti-fungal agents. An internal standard diazepam was added to 100 microL of human plasma followed by 3 mL of hexane-methylene chloride (70:30, v/v). The organic layer was evaporated to dryness and the residue was reconstituted with 100 microL of mobile phase before being injected in the chromatographic system. The compounds were separated on a C8 column using sodium potassium phosphate buffer (0.04 M, pH 6.0): acetonitrile:ultrapure water (45:52.5:2.5, v/v/v) as mobile phase. All compounds were detected at a wavelength of 255 nm. The assay was linear and validated over the range 0.2-10.0 mg/L for voriconazole and 0.05-10.0 mg/L for posaconazole. The biases were comprised between -3 and 5% for voriconazole and -2 and 8% for posaconazole. The intra- and inter-day precisions of the method were lower than 8% for the routine quality control (QC). The mean recovery was 98% for voriconazole and 108% for posaconazole. This method provides a useful tool for therapeutic drug monitoring.     

Quantification of tipranavir in human plasma by high-performance liquid chromatography with UV detection

A simple method for the quantification of tipranavir, a new non-peptidic protease-inhibitor, was developed. An internal standard, prazepam, was added to 100 microl of plasma before a liquid-liquid extraction by 3 ml of tert-butyl methyl ether. The extracts were evaporated to dryness and reconstituted with 100 microl of mobile phase before being injected in the chromatographic system. The separation was made on a C8 column using sodium acetate buffer (pH 5):methanol:acetonitrile (35:30:35, v/v/v) as mobile phase. The detection was performed at a wavelength of 260 nm. The method was linear and has been validated over a concentration range of 2-80 mg/l. The mean precision and accuracy of the method were respectively, 10.5 and -9.1%. The mean recovery was 70.8%.     

Quantitative analysis of racecadotril metabolite in human plasma using a liquid chromatography/tandem mass spectrometry

Orally administered racecadotril is rapidly hydrolyzed to the more potent enkephalinase inhibitor thiorphan in vivo. A sensitive and specific liquid chromatography/tandem mass spectrometry method was developed and validated to quantify thiorphan in human plasma using lisinopril as the internal standard. After a simple protein precipitation with methanol, the post-treatment samples were analyzed on a CN column interfaced with a triple-quadruple tandem mass spectrometer using negative electrospray ionization. The method was validated to demonstrate the specificity, lower limit of quantification, accuracy, and precision of measurements. The assay was linear over the concentration range 9.38-600 ng/mL using a 5 microL aliquot of plasma. The correlation coefficients for the calibration curves ranged from 0.9985 to 0.9995. The intra- and inter-day precisions over the entire concentration were not more than 6.33%. Methanol and water (35:65, v/v) is used as the isocratic mobile phase, with 0.1% of formic acid in water. The method was successfully applied for pharmacokinetic study after a single oral administration of 200 mg racecadotril to 20 healthy volunteers.     

Development and validation of a selective and robust LC-MS/MS method for high-throughput quantifying rizatriptan in small plasma samples: application to a clinical pharmacokinetic study

An analytical method based on liquid chromatography with positive ion electrospray ionization (ESI) coupled to tandem mass spectrometry detection (LC-MS/MS) was developed for the determination of a potent 5-HT(1B/1D) receptor agonist, rizatriptan in human plasma using granisetron as the internal standard. The analyte and internal standard were isolated from 100 microL plasma samples by liquid-liquid extraction (LLE) and chromatographed on a Lichrospher C18 column (4.6mm x 50mm, 5 microm) with a mobile phase consisting of acetonitrile-10mM aqueous ammonium acetate-acetic acid (50:50:0.5, v/v/v) pumped at 1.0 mL/min. The method had a chromatographic total run time of 2 min. A Varian 1200 L electrospray tandem mass spectrometer equipped with an electrospray ionization source was operated in selected reaction monitoring (SRM) mode with the precursor-to-product ion transitions m/z 270-->201 (rizatriptan) and 313.4-->138 (granisetron) used for quantitation. The assay was validated over the concentration range of 0.05-50 ng/mL and was found to have acceptable accuracy, precision, linearity, and selectivity. The mean extraction recovery from spiked plasma samples was above 98%. The intra-day accuracy of the assay was within 12% of nominal and intra-day precision was better than 13% C.V. Following a 10mg dose of the compound administered to human subjects, mean concentrations of rizatriptan ranged from 0.2 to 70.6 ng/mL in plasma samples collected up to 24h after dosing. Inter-day accuracy and precision results for quality control samples run over a 5-day period alongside clinical samples showed mean accuracies of within 12% of nominal and precision better than 9.5% C.V.     

Simultaneous determination of OSI-774 and its major metabolite OSI-420 in human plasma by using HPLC with UV detection

A new method was developed and validated for quantitating OSI-774 and its metabolite OSI-420 in human plasma. Sample preparation involved initial extraction with methyl t-butyl ether followed by back extraction with HCl and re-extraction with methyl t-butyl ether. This extraction process resulted in significant improvement in the specificity, reproducibility and sensitivity. The analytes were separated on a Water Symmetry C18 analytical column and the mobile phase consisted of acetonitrile-0.05 M potassium phosphate buffer (42:58, v/v) (pH 4.8), and monitored at a wavelength 345 nm. Values of between- and within-day precision and accuracy for both OSI-774 and OSI-420 were <20%. This method was successfully applied to study steady-state pharmacokinetics of OSI-774 and OSI-420 in a phase II clinical trial.     

Determination of scutellarin in rat plasma by high-performance liquid chromatography with ultraviolet detection

A validated high-performance liquid chromatography method is described for the determination of scutellarin in rat plasma using a liquid-liquid extraction and ultraviolet (UV) absorbance detection. The separation used a Diamonsil ODS column (250 mm x 4.6mm i.d., 5 microm particle size) with an isocratic mobile phase consisting of methanol-acetonitrile-50mM dihydrogen ammonium phosphate buffer (22:15:63 (v/v/v), adjusted to pH 2.5 with 1M phosphoric acid). The ultraviolet detector operated at 335 nm. Plasma samples were extracted with ethyl acetate after acidification. The extraction recovery of scutellarin ranged from 68.1 to 80.5%. High selectivity and a low quantitation limit (0.050 microg/ml) were achieved. The linear range was 0.050-12.5 microg/ml, correlation coefficient r=0.9981. The method has a good reproducibility, R.S.D. values were below 7.9% for within-day and between-day precision. The method is simple, rapid, and applicable to preliminary pharmacokinetic studies of scutellarin in rats.     

Determination of ragaglitazar,a novel dual acting peroxisome proliferator-activated receptor (PPAR) alpha and -gamma agonist,in human plasma by high-performance liquid chromatography coupled with tandem mass spectrometry

A sensitive and specific LC/MS/MS method has been developed and validated for determination of ragaglitazar (NNC 61-0029 or DRF 2725) in human plasma. After solid-phase extraction (SPEC((R)) PLUS C(8)) of plasma, separation was performed on a Symmetry Shield RP8 column (mobile phase: acetonitrile: 10 mM ammonium acetate, pH 5.6 (40:60 v/v)). Two ranges were validated having LLOQs of either 0.500 or 100 ng/ml and linearity up to either 500 or 50000 ng/ml. The intra-assay precision and accuracy were 1.1% to 15.7% and 85.8% to 118.2% (range 0.500-500 ng/ml) and 2.0% to 8.8% and 92.9% to 104.8% (range 100-50000 ng/ml). The method was applied for determination of ragaglitazar in plasma from phase 1 and 2 clinical studies.     

Determination of MS-275, a novel histone deacetylase inhibitor, in human plasma by liquid chromatography-electrospray mass spectrometry

A rapid method was developed for the quantitative determination of the novel histone deacetylase inhibitor, MS-275, in human plasma. Calibration curves were constructed in the range of 1-100 ng/ml, and were analyzed using a weight factor proportional to the nominal concentration. Sample pretreatment involved a one-step protein precipitation with acetonitrile of 0.1 ml samples. The analysis was performed on a column (75 mm x 4.6 mm i.d.) packed with 3.5 microm Phenyl-SB material, using methanol-10mM ammonium formate (55:45 (v/v)) as the mobile phase. The column effluent was monitored by mass spectrometry with positive electrospray ionization. The values for precision and accuracy were always < or =5.58 and <11.4% relative error, respectively. The method was successfully applied to examine the pharmacokinetics of MS-275 in a cancer patient.     

Validation and implementation of a method for determination of bryostatin 1 in human plasma by using liquid chromatography/tandem mass spectrometry

A new sensitive and specific method using liquid chromatography/tandem mass spectrometry for determination of bryostatin 1 was developed and validated. Sample pretreatment involved a double liquid-liquid extraction step with a mixture of acetonitrile/n-butyl chloride (1/4, v/v). Separation of the compound of interest, including the internal standard paclitaxel, was achieved on a Waters X-Terra C18 (50 x 2.1 mm i.d., 3.5 microm) analytical column with acetonitrile/water mobile phase (80:20, v/v) containing 0.1% formic acid using isocratic flow at 0.15 mL/min for 13 min. The analytes of interest were monitored by tandem mass spectrometry with electrospray positive ionization. The linear calibration curves were generated over the range of 50-2000 pg/mL with values for the coefficient of determination of >0.99. The values for both within-day and between-day precision and accuracy were <15%. This method was used to characterize the plasma pharmacokinetics of bryostatin 1 at doses of 20 microg/m2) to optimize treatment with this agent.     

Simultaneous liquid chromatographic determination of lamotrigine, oxcarbazepine monohydroxy derivative and felbamate in plasma of patients with epilepsy

A very simple and fast method has been developed and validated for simultaneous determination of the new generation antiepileptic drugs (AEDs) lamotrigine (LTG), oxcarbazepine's (OXC) main active metabolite monohydroxycarbamazepine and felbamate in plasma of patients with epilepsy using high-performance liquid chromatography (HPLC) with spectrophotometric detection. Plasma sample (500 microL) pre-treatment was based on simple deproteinization by acetonitrile. Liquid chromatographic analysis was carried out on a Synergi 4 microm Hydro-RP, 150 mm x 4 mm I.D. column, using a mixture of potassium dihydrogen phosphate buffer (50mM, pH 4.5) and acetonitrile/methanol (3/1) (65:35, v/v) as the mobile phase, at a flow rate of 1.0 mL/min. The UV detector was set at 210 nm. Calibration curves were linear (mean correlation coefficient >0.999 for all the three analytes) over a range of 1-20 mg/mL for lamotrigine, 2-40 microg/mL for monohydroxycarbamazepine and 10-120 microg/mL for felbamate. Both intra and interassay precision and accuracy were lower than 7.5% for all three analytes. Absolute recoveries ranged between 100 and 104%. The present procedure describes for the first time the simultaneous determination of these three new antiepileptic drugs. The simple sample pre-treatment, combined with the fast chromatographic run permit rapid processing of a large series of patient samples.     

Determination of Cloretazine (VNP40101M) and its active metabolite (VNP4090CE) in human plasma by liquid chromatography electrospray tandem mass spectrometry (LC-ESI-MS/MS)

A sensitive method for the determination of Cloretazine (VNP40101M) and its metabolite (VNP4090CE) with an internal standard (ISTD) in human plasma was developed using high-performance liquid chromatographic separation with tandem mass spectrometric detection. Acidified plasma samples (500 microL) were prepared using solid phase extraction (SPE) columns, and 25 microL of the reconstituted sample was injected onto an Ascentis C18 HPLC column (3 microm, 5 cmx2.1 mm) with an isocratic mobile phase. Analytes were detected with an API-3000 LC-MS/MS System at unit (Q1) and low (Q3) resolution in negative multiple reaction monitoring mode: m/z 249.0 (precursor ion) to m/z 114.9 (product ion) for both Cloretazine (at 3.64 min) and VNP4090CE (at 2.91 min), and m/z 253.0 (precursor ion) to m/z 116.9 (product ion) for the ISTD. The mean recovery for Cloretazine (VNP40101M) and its metabolite (VNP4090CE) was greater than 87% with a lower limit of quantification of 1.0 ng/mL for Cloretazine (S/N=9.7, CV相似文献   

Electrospray ionization LC-MS/MS validated method to quantify griseofulvin in human plasma and its application to bioequivalence study

A simple, sensitive and rapid liquid chromatography/tandem mass spectrometry (LC-MS/MS) method has been developed and validated to quantify griseofulvin in human plasma using propranolol hydrochloride as internal standard (IS). Samples were prepared using solid phase extraction and analysed without drying and reconstitution. The analytes were chromatographed on Hypersil, hypurity C18 reverse phase column under isocratic conditions using 0.05% formic acid in water:acetonitrile (30:70, v/v) as the mobile phase. Total chromatographic run time was 3.0 min. Quantitation was done on a triple quadrupole mass analyzer API-3000, equipped with turbo ion spray interface and operating in multiple reaction monitoring (MRM) mode to detect parent-->product ion transition for analyte and IS. The method was validated for sensitivity, matrix effect, accuracy and precision, linearity, recovery and stability studies. Linearity in plasma was observed over the concentration range 20-3000 ng/mL for griseofulvin. Lower limit of quantification (LLOQ) achieved was 20 ng/mL with precision (CV) less than 10% using 5 microL injection volume. The absolute recovery of analyte (87.36%) and IS (98.91%) from spiked plasma samples was consistent and reproducible. Inter-batch and intra-batch coefficients of variation across four validation runs (LLOQ, LQC, MQC and HQC) was less than 7.5%. The accuracy determined at these levels was within +/-4.2% in terms of relative error. The method was applied to a pilot bioequivalence study of 500 mg griseofulvin tablet in six healthy human subjects under fed condition.     

Quantification of zolmitriptan in plasma by high-performance liquid chromatography-electrospray ionization mass spectrometry

A sensitive and specific liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) method has been developed and validated for the identification and quantification of zolmitriptan in human plasma. After the addition of the internal standard (IS) and 1.0 M sodium hydroxide solution, plasma samples were extracted with methylene chloride:ethyl acetate mixture (20:80, v/v). The organic layer was evaporated under a stream of nitrogen at 40 degrees C. The residue was reconstituted with 100 microl mobile phase. The compounds were separated on a prepacked Lichrospher CN (5 microm, 150 mm x 2.0 mm) column using a mixture of methanol:water (10 mM NH(4)AC, pH 4.0) = 78:22 as mobile phase. Detection was performed on a single quadrupole mass spectrometer by selected ion monitoring (SIM) mode via electrospray ionization (ESI) source. The method was proved to be sensitive and specific by testing six different plasma batches. Linearity was established for the range of concentrations 0.30-16.0 ng/ml with a coefficient of determination (r) of 0.9998 and good back-calculated accuracy and precision. The intra- and inter-day precision (R.S.D.%) were lower than 15% and accuracy ranged from 85 to 115%. The lower limit of quantification was identifiable and reproducible at 0.30 ng/ml. The proposed method enables the unambiguous identification and quantification of zolmitriptan for pharmacokinetic, bioavailability or bioequivalence studies.     

Chiral analysis of butaclamol enantiomers in human plasma by HPLC using a macrocyclic antibiotic (vancomycin) chiral stationary phase and solid phase extraction

An enantioseparation of the antipsychotic drug butaclamol in human plasma by high-performance liquid chromatography (HPLC) with solid phase extraction is presented. The separation was achieved on the vancomycin macrocyclic antibiotic chiral stationary phase (CSP) Chirobiotic V with a polar ionic mobile phase (PIM) consisting of methanol : glacial acetic acid : triethylamine (100:0.2:0.05, v/v/v) at a flow rate of 0.5 ml/min. The detection wavelength was 262 nm. Bond Elut C18 solid phase extraction cartridges were used in the sample preparation of butaclamol samples from plasma. The method was validated over the range of 100-3,000 ng/ml for each enantiomer concentration (R(2) > 0.999). Recoveries for (+)- and (-)-butaclamol were in the range of 94-104% at the 300-2,500 ng/ml level. The method proved to be precise (within-run precision ranged from 1.1-2.6% and between-run precision ranged from 1.9-3.2%) and accurate (within-run accuracies ranged from 1.5-5.8% and between-run accuracies ranged from 2.7-7.7%). The limit of quantitation (LOQ) and limit of detection (LOD) for each enantiomer in human plasma were 100 ng/ml and 50 ng/ml, respectively.     

High performance liquid chromatographic determination of azithromycin in serum using fluorescence detection and its application in human pharmacokinetic studies

A fast and sensitive high-performance liquid chromatographic method for determination of azithromycin in human serum using fluorescence detection was developed. The drug and an internal standard (clarithromycin) were extracted from serum using n-hexan and subjected to pre-column derivatization with 9-fluorenylmethyl chloroformate as labeling agent. Analysis was performed on a phenyl packing material column with sodium phosphate buffer containing 2 ml/l triethylamine (pH 5.9) and methanol (29:71, v/v) as the mobile phase. The standard curve was linear over the range of 10-500 ng/ml of azithromycin in human serum. The means between-days precision were from 13.3% (for 10 ng/ml) to 2% (500 ng/ml) and the within-day precision from 11.9 to 1.7% determined on spiked samples. The accuracy of the method was 100.7-107.2% (between days) and 100.3-107.8% (within day). The limit of quantification was 10 ng/ml. This method was applied in a bioequivalence study of four different azithromycin preparations in 12 healthy volunteers.     

Simultaneous quantification of tracheloside and trachelogenin in rat plasma using liquid chromatography/tandem mass spectrometry

We developed and validated a quantitative method for simultaneously determining the concentrations of tracheloside and trachelogenin in rat plasma. Plasma samples were prepared by liquid-liquid extraction with ethyl acetate. Isocratic chromatographic separation was performed on a reversed-phase Diamonsil C(18) column (4.6×200 mm, 5 μm). The mobile phase consisted of methanol and 10mM aqueous ammonium formate (80:20, v/v). Analyte detection was achieved by positive electrospray ionization (ESI) tandem mass spectrometry. Calibration was performed by internal standardization with glipizide, and regression curves ranging from 0.625 to 625 ng/mL were constructed for both the analytes. The intra- and inter-day precision values were below 8%, and accuracy ranged from -5.33% to 2.53% in all quality control samples. In this study, the validated method was successfully applied to determine the pharmacokinetic profile of tracheloside and trachelogenin in rat plasma after oral and intravenous administration of trachelospermi total lignans.     

Quantitative determination of the anticancer agent tubeimoside I in rat plasma by liquid chromatography coupled with mass spectrometry

Tubeimoside I is an important component isolated from Bolbostemma paniculatum. Tubeimoside I has been demonstrated to possess many pharmacological activities, including anti-inflammatory, antitumor, and antitumor-promoting effects. The purpose of the present study was to examine in vivo pharmacokinetics and bioavailability of tubeimoside I in rats by using a liquid chromatography coupled with mass spectrometry quantitative detection method (LC/MS). The plasma samples were deproteinated, evaporated and reconstituted in 100 microl methanol prior to analysis. The separation was performed by Waters Symmetry C18 reversed-phase column (3.5 microm, 150 mm x 2.1mm, Waters Inc., USA) and a SB-C18 guard column (5 microm, 20 mm x 4.0mm). The mobile phase was a mixture of acetonitrile and water containing 5 microM NaAc (60:40, v/v). The method was validated within the concentration range 20-5000 ng/ml, and the calibration curves were linear with correlation coefficients >0.999. The lowest limit of quantitation (LLOQ) for tubeimoside I was 20 ng/ml in 0.1 ml rat plasma. The intra-assay accuracy and precision ranged from 92.4 to 104.9% and from 5.8 to 10.5%, respectively, while inter-assay accuracy and precision ranged from 94.2 to 95.0% and from 5.1 to 8.8%, respectively. The method was further applied to assess pharmacokinetics and oral bioavailability of tubeimoside I after intravenous and oral administration to rats. The oral bioavailability of tubeimoside I is only 0.23%, which indicates that tubeimoside I has poor absorption or undergoes acid-induced degradation. Practical utility of this new LC/MS method was confirmed in pilot pharmacokinetic studies in rats following both intravenous and oral administration.