Determination of unbound vismodegib (GDC-0449) concentration in human plasma using rapid equilibrium dialysis followed by solid phase extraction and high-performance liquid chromatography coupled to mass spectrometry

A rapid equilibrium dialysis (RED) assay followed by a solid phase extraction (SPE) high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for the quantitative determination of unbound vismodegib in human plasma was developed and validated. The equilibrium dialysis was carried out using 0.3 mL plasma samples in the single-use plate RED system at 37°C for 6h. The dialysis samples (0.1 mL) were extracted using a Strata-X-C 33u Polymeric Strong Cation SPE plate and the resulting extracts were analyzed using reverse-phase chromatography and positive electrospray ionization (ESI) mass spectrometry. The standard curve, which ranged from 0.100 to 100 ng/mL for vismodegib, was fitted to a 1/x(2) weighted linear regression model. The lower limit of quantitation (LLOQ, 0.100 ng/mL) was sufficient to quantify unbound concentrations of vismodegib after dialysis. The intra-assay precision of the LC-MS/MS assay, based on the four analytical QC levels (LLOQ, low, medium and high), was within 7.7% CV and inter-assay precision was within 5.5% CV. The assay accuracy, expressed as %Bias, was within ±4.0% of the nominal concentration values. Extraction recovery of vismodegib was between 77.9 and 84.0%. The assay provides a means for accurate assessment of unbound vismodegib plasma concentrations in clinical studies.     

Validation and implementation of a liquid chromatography/tandem mass spectrometry assay to quantitate ON 01910.Na, a mitotic progression modulator, in human plasma

A reverse-phase high performance liquid chromatographic method with tandem mass spectrometry (LC-MS/MS) was developed and validated for the quantitation of ON 01910.Na, a novel synthetic benzyl styryl sulfone, in human plasma. The assay involved a simple sample preparation with acetonitrile protein precipitation. ON 01910.Na and the internal standard temazepam were separated on a Waters X-Terra MS C(18) column with mobile phase of acetonitrile containing 0.1% formic acid /10mM ammonium acetate (55:45, v/v) using isocratic flow at 0.2 mL/min for 5 min. The analytes were monitored by tandem-mass spectrometry with electrospray positive ionization. Two calibration curves were generated over the range of 10-2000 ng/mL and 100-20000 ng/mL. The lower limit of quantitation (LLOQ) was 10 ng/mL for ON 01910.Na in human plasma. The accuracy and within- and between-day precisions were within the acceptance criteria for bioanalytical assays. ON 01910.Na was found stable in plasma at -70 degrees C for at least 1 year. The method was successfully applied to characterize the plasma concentration-time profiles of ON 01910.Na in the cancer patients in the Phase I study.     

Development and validation of Lenalidomide in human plasma by LC-MS/MS

A highly sensitive and ultra-fast high performance liquid chromatography- tandem mass spectrometry (LC–MS/MS) assay is developed and validated for the quantification of Lenalidomide in human plasma. Lenalidomide is extracted from human plasma by Liquid- Liquid Extraction by Ethyl Acetate and analyzed using a reversed phase isocratic elution on a XTerra RP18, (4.6 × 50 mM, 5 µm) column. A 0.1% Formic acid: Methanol (10:90% v/v), is used as mobile phase and detection was performed by Triple quadrupole mass spectrometry LC-MS/MS using electrospray ionization in positive mode. Fluconazole is used as the internal standard. The lower limit of quantification is 9.999 ng/mL for Lenalidomide. The calibration curves are consistently accurate and precise over the concentration range of 9.999 to 1010.011 ng/mL in plasma for Lenalidomide. This novel LC–MS/MS method competes with all the regulatory requirements and shows satisfactory accuracy and precision and is sufficiently sensitive for the performance of pharmacokinetic and bioequivalence studies in humans.     

Validation and implementation of a liquid chromatography/tandem mass spectrometry assay to quantitate aminoflavone (NSC 686288) in human plasma

A reverse-phase liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) method was developed and validated for determination of aminoflavone (AF) in human plasma. Sample preparation involved a liquid–liquid extraction by the addition of 0.25 mL of plasma with 1.0 mL ethyl acetate containing 50 ng/mL of the internal standard zileuton. The analytes were separated on a Waters X-Terra? MS C₁₈ column using a mobile phase consisting of methanol/water containing 0.45% formic acid (70:30, v/v) and isocratic flow at 0.2 mL/min for 6 min. The analytes were monitored by tandem mass spectrometry with electrospray positive ionization. Linear calibration curves were generated over the AF concentration range of 5–2000 ng/mL in human plasma. The lower limit of quantitation (LLOQ) was 5 ng/mL for AF in human plasma. The accuracy and within- and between-day precisions were within the generally accepted criteria for bioanalytical method (<15%). This method was successfully applied to characterize AF plasma concentration-time profile in the cancer patients in a phase I trial.     

Simultaneous determination of glycyrrhizin, a marker component in radix Glycyrrhizae, and its major metabolite glycyrrhetic acid in human plasma by LC-MS/MS

Glycyrrhizin (GLY) which has been widely used in traditional Chinese medicinal preparation possesses various pharmacological effects. In order to investigate the pharmacokinetic behavior of GLY in human after oral administration of GLY or licorice root, a liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of GLY and its major metabolite glycyrrhetic acid (GA) in human plasma. The method involved a solid phase extraction of GLY, GA, and alpha-hederin, the internal standard (IS), from plasma with Waters Oasis MCX solid phase extraction (SPE) cartridges (30 mg) and a detection using a Micromass Quattro LC liquid chromatography/tandem mass spectrometry system with electrospray ionization source in positive ion mode. Separation of the analytes was achieved within 5min on a SepaxHP CN analytical column with a mobile phase of acetonitrile:water (50:50, v:v) containing 0.1% formic acid and 5mM ammonium acetate. Multiple reaction monitoring (MRM) was utilized for the detection monitoring 823--> 453 for GLY, 471--> 177 for GA and 752--> 456 for IS. The LC-MS/MS method was validated for specificity, sensitivity, accuracy, precision, and calibration function. The assay had a calibration range from 10 to 10,000 ng/mL and a lower limit of quantification of 10 ng/mL for both GLY and GA when 0.2 mL plasma was used for extraction. The percent coefficient of variation for accuracy and precision (inter-run and intra-run) for this method was less than 11.0% with a %Nominal ranging from 87.6 to 106.4% for GLY and 93.7 to 107.8% for GA. Stability of the analytes over sample processing (freeze/thaw, bench-top and long-term storage) and in the extracted samples was also tested and established.     

Liquid chromatography-tandem mass spectrometry method for determination of N-acetylglucosamine concentration in human plasma

A simple, reliable and sensitive liquid chromatography-tandem mass spectrometry method (LC-MS/MS) was developed and validated for quantification of N-acetylglucosamine in human plasma. Plasma samples were pretreated with acetonitrile for protein precipitation. The chromatographic separation was performed on Hypersil Silica column (150mmx2mm, 5microm). The deprotonated analyte ion was detected in negative ionization mode by multiple reaction monitoring mode. The mass transition pairs of m/z 220.3-->118.9 and m/z 226.4-->123.2 were used to detect N-acetylglucosamine and internal standard 13C6-N-acetylglucosamine, respectively. The assay exhibited a linear range from 20 to 1280ng/ml for N-acetylglucosamine in human plasma. Acceptable precision and accuracy were obtained for concentrations of the calibration standard and quality control. The validated method was successfully applied to analyze human plasma samples in a pharmacokinetic study.     

Determination of cediranib in mouse plasma and brain tissue using high-performance liquid chromatography-mass spectrometry

A new high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) assay for cediranib, a tyrosine kinase inhibitor for VEGFRs, was developed and validated, for the determination of plasma and brain levels of cediranib in small specimen volumes. Tyrphostin (AG1478) was used as internal standard. Mouse plasma and brain homogenate samples were prepared using liquid-liquid extraction. The assay was validated for a 2.5-2500 ng/mL concentration range for plasma, and for 1-2000 ng/mL range for brain homogenate. For these calibration ranges, within-assay variabilities were 1.1-14.3% for plasma and 1.5-9.4% for brain homogenate; between-assay variabilities were 2.4-9.2% for plasma, and 4.9-10.2% for brain homogenate. Overall accuracy ranged from 101.5 to 107.0% for plasma and 96.5 to 100.2% for brain homogenate, for all target concentrations. The developed assay has been successfully applied for a brain distribution study in mice at an oral dose of 5 mg/kg.     

Development and validation of an LC-MS/MS method for the quantitative determination of aripiprazole and its main metabolite, OPC-14857, in human plasma

An accurate, sensitive, reproducible, and selective liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for determination of aripiprazole and its main metabolite, OPC-14857, in human plasma was developed and validated. Chromatographic separation was achieved isocratically on a C18 reversed-phase column within 7.5 min. The calibration curve, ranging from 0.1 to 100 ng/ml, was fitted to a 1/y2-weighted linear regression model. The assay showed no significant interference. Lower limit of quantitation (LLOQ) for both analytes was 0.1 ng/ml using 0.4 ml of plasma. Intra- and inter-assay precision and accuracy values for aripiprazole and OPC-14857 were within regulatory limits.     

Selective and sensitive liquid chromatography-tandem mass spectrometry method for the determination of levonorgestrel in human plasma

A selective, sensitive and rapid liquid chromatography-tandem mass spectrometry method for the determination of levonorgestrel in plasma was developed. An Applied Biosystems API 3000 triple quadrupole mass spectrometer set to multiple reaction monitoring (MRM) mode, using atmospheric pressure photospray ionisation (APPI) in the positive mode. Using 17-alpha-methyltestosterone as internal standard (IS), liquid-liquid extraction was followed by reversed phase liquid chromatography using a phenyl-hexyl column and tandem mass spectrometric detection. The mean recovery for levonorgestrel and 17-alpha-methyltestosterone was 99.5 and 62.9%, respectively. The method was validated from 0.265 to 130 ng levonorgestrel/ml plasma with the lower limit of quantification (LLOQ) set at 0.265 ng/ml. This assay method makes use of the increased sensitivity and selectivity of tandem mass spectrometric (MS/MS) detection, allowing for a rapid (extraction and chromatography) and selective method for the determination of levonorgestrel in human plasma. The assay method was used in a pharmacokinetic study to quantify levonorgestrel in human plasma samples generated after administrating a single oral dose of 1.5 mg levonorgestrel to healthy female volunteers for up to five half lives. The total chromatographic runtime of this method was 5.0 min per sample, allowing for analysis of a large number of samples per batch.     

Quantification of apolipoprotein A-I mimetic peptide D-4F in rabbit plasma by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry

The apolipoprotein A-I mimetic peptide D-4F is a potential therapeutical agent effective in maintaining cardiovascular health. A bioanalytical assay based on high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC/MS/MS) to quantitate the D-4F amount in rabbit plasma was developed and validated. A compound with a close structure similarity to the D-4F (only one amino acid A–V altered) was used as an internal standard. Both D-4F and the internal standard were extracted by protein precipitation using acetonitrile/0.2% Triton XL 80N. The correlation coefficient of the calibration curve was 0.9991 in the range 20–40,000 ng/mL. This assay can be used for pharmacokinetic studies of the drug. Also, it may be adjusted for the quantification of other members of apolipoprotein A-I mimetic peptide family.     

Quantitative analysis of Variolin analog (PM01218) in mouse and rat plasma by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry

PM01218 is a novel marine-derived alkaloid and has shown potent growth inhibitory activity against several human cancer cell lines. A rapid and sensitive high performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) method was developed and validated to quantify PM01218 in mouse and rat plasma. The lower limit of quantitation (LLOQ) was 0.05 ng/mL. The calibration curve was linear from 0.05 to 100 ng/mL (R(2)>0.999). The assay was specifically based on the multiple reaction monitoring (MRM) transitions at m/z 278.4-->184.2, no endogenous material interfaced with the analysis of PM01218 and its internal standard from blank mouse and rat plasma. The mean intra- and inter-day assay accuracy remained below 15 and 8%, respectively, for all calibration standards and QC samples. The intra- and inter-day assay precision was less than 12.8 and 8.5% for all QC levels, respectively. The utility of the assay was demonstrated by pharmacokinetics studies of i.v. (bolus) PM01218 on SD rats.     

Rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of clonidine in human plasma

A rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the estimation of clonidine in human plasma. Clonidine was extracted from human plasma by using solid-phase extraction technique. Nizatidine was used as the internal standard. A Hypurity C18 (50 mm x 4.6 mm i.d., 5 microm particle size) column provided chromatographic separation of analyte followed by detection with mass spectrometry. The method involves a rapid solid-phase extraction from plasma, simple isocratic chromatography conditions and mass spectrometric detection that enables detection up to picogram levels with a total run time of 3.0 min only. The method was validated over the range of 50-2500 pg/mL. The absolute recoveries for clonidine (71.86%) and IS (69.44%) achieved from spiked plasma samples were consistent and reproducible.     

Ultra-sensitive determination of Formoterol in human serum by high performance liquid chromatography and electrospray tandem mass spectrometry

An analytical method was developed and validated to determine Formoterol in human serum in the range from 0.40 to 100.24 pg/mL by high performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS) due to the lack of efficient methods to determine very low levels of Formoterol in serum and plasma. Serum was diluted by water and mixed with the internal standard (d6-Formoterol). Formoterol and internal standard were extracted using a cation-exchange solid phase column (SCX-3). After eliminating endogenous serum constituents through washing steps with water and methanol, elution took place using methanol/ammonia. After evaporation of the elution liquid the residue was redissolved and analyzed by HPLC-MS/MS with electrospray ionisation (ESI) in positive mode. A gradient between 10 mM ammonium formate and acetonitrile was used. The inter-batch precision of the calibration standards ranged from 1.55% to 9.01%. The inter-batch accuracy of the calibration standards ranged from 93.37% to 107.30%. The lower limit of quantitation (LLOQ, 0.40 pg/mL) had a precision of 19.67% and an accuracy of 96.78%. Comparable results were obtained for quality control samples. Stability in human serum was given over three freeze/thaw cycles and 2h at room temperature. Formoterol in human serum was stable for at least 6 months below -20 degrees C. This method has been used widely for quantifying Formoterol after inhalation of 9-36 microg of the drug by volunteers. A cross validation with human plasma versus serum was performed after this method was successfully validated in human serum.     

Determination of GDC-0449, a small-molecule inhibitor of the Hedgehog signaling pathway,in human plasma by solid phase extraction-liquid chromatographic-tandem mass spectrometry

To support clinical development, a solid phase extraction (SPE) liquid chromatographic-tandem mass spectrometry (LC-MS/MS) method for the determination of GDC-0449 concentrations in human plasma has been developed and validated. Samples (200 μl) were extracted using an Oasis MCX 10 mg 96-well SPE plate and the resulting extracts were analyzed using reverse-phase chromatography coupled with a turbo-ionspray interface. The method was validated over calibration curve range 5–5000 ng/mL. Quadratic regression and 1/x² weighing were used. Within-run relative standard deviation (%RSD) was within 10.1% and accuracy ranged from 88.6% to 109.0% of nominal. Between-run %RSD was within 8.6% and accuracy ranged from 92.4% to 105.3% of nominal. Extraction recovery of GDC-0449 was between 88.3% and 91.2% as assessed using quality control sample concentrations. GDC-0449 was stable in plasma for 315 days when stored at ?70 °C and stable in reconstituted sample extracts for 117 h when stored at room temperature. Quantitative matrix effect/ion suppression experiment was performed and no significant matrix ion suppression was observed. This assay allows for the determination of GDC-0449 plasma concentrations over a sufficient time period to determine pharmacokinetic parameters at relevant clinical doses.     

Ultra sensitive determination of limaprost, a prostaglandin E1 analogue, in human plasma using on-line two-dimensional reversed-phase liquid chromatography-tandem mass spectrometry

A highly sensitive and selective method has been developed and validated to determine limaprost, a prostaglandin (PG) E(1) analogue, in human plasma by on-line two-dimensional reversed-phase liquid chromatography-tandem mass spectrometry (2D-LC/MS/MS) due to the lack of efficient methods to determine very low levels of limaprost in plasma. Limaprost and its deuterium derivatives, used as internal standard, were extracted by protein precipitation and following three-step solid phase extractions. After extraction procedure, samples were analyzed by on-line 2D-LC/MS/MS with electrospray ionization in negative mode. The 2D-LC system consists of Phenyl column at first dimension and ODS at second dimension with a trapping column placed between the separation columns. The linear dynamic range of this method was 0.1-10 pg/ml with 3 ml of plasma (r >0.9987). Acceptable precision and accuracy were obtained over the calibration curve ranges. The assay has been successfully used in analyses of human plasma samples to support clinical pharmacokinetics studies.     

Microdose clinical trial: quantitative determination of fexofenadine in human plasma using liquid chromatography/electrospray ionization tandem mass spectrometry

A sample treatment procedure and high-sensitive liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method for quantitative determination of fexofenadine in human plasma was developed for a microdose clinical trial with a cold drug, i.e., a non-radioisotope-labeled drug. Fexofenadine and terfenadine, as internal standard, were extracted from plasma samples using a 96-well solid-phase extraction plate (Oasis HLB). Quantitation was performed on an ACQUITY UPLC system and an API 5000 mass spectrometer by multiple reaction monitoring. Chromatographic separation was achieved on an XBridge C18 column (100 mm x 2.1 mm i.d., particle size 3.5 microm) using acetonitrile/2 mM ammonium acetate (91:9, v/v) as the mobile phase at a flow rate of 0.6 ml/min. The analytical method was validated in accordance with the FDA guideline for validation of bioanalytical methods. The calibration curve was linear in the range of 10-1000 pg/ml using 200 microl of plasma. Analytical method validation for the clinical dose, for which the calibration curve was linear in the range of 1-500 ng/ml using 20 microl of plasma, was also conducted. Each method was successfully applied for making determinations in plasma using LC/ESI-MS/MS after administration of a microdose (100 microg solution) and a clinical dose (60 mg dose) in eight healthy volunteers.     

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.     

A high throughput and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the estimation of bisoprolol in human plasma using multiplexing technique

A high throughput and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the estimation of bisoprolol in human plasma using multiplexing technique (two HPLC units connected to one MS). Bisoprolol was extracted from human plasma using solid-phase extraction technique using metoprolol as internal standard. A Betabasic 8 column provided chromatographic separation of analytes followed by detection with mass spectrometry. The mass transition ion-pair was followed as m/z 326.2-->116.1 for bisoprolol and m/z 268.2-->191.0 for metoprolol. The method involves a simple multiplexing, rapid solid-phase extraction, simple isocratic chromatography conditions and mass spectrometric detection which enable detection at sub-nanogram levels. The proposed method has been validated for a linear range of 0.5-70.0 ng/mL with correlation coefficient > or =0.9991. The precision and accuracy were within 10% for intra-HPLC runs and inter-HPLC runs. The overall recoveries for bisoprolol and metoprolol were 93.89% and 77.65%, respectively. Total MS run time was 0.90 min only. The developed method was applied for the determination of pharmacokinetic parameters of bisoprolol following a single oral administration of a 10mg bisoprolol tablet in 18 healthy male volunteers.     

Determination of olopatadine, a new antiallergic agent, and its metabolites in human plasma by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry

A rapid, sensitive and specific assay method has been developed to determine plasma concentrations of olopatadine hydrochloride (A) and its metabolites, M1 (B), M2 (C) and M3 (D), using high-performance liquid chromatography with electrospray ionization tandem mass spectrometry (LC–ESI-MS–MS). Olopatadine, its metabolites, and internal standard, KF11796 (E), were separated from plasma using solid-phase extraction (Bond Elut C₁₈ cartridge). The eluate was dried, reconstituted and injected into the LC–ESI-MS–MS system. The calibration curves showed good linearity over the ranges 1–200 ng/ml for olopatadine and M3, and 2–100 ng/ml for M1 and M2, and the method was thoroughly validated and applied to the determination of olopatadine and its metabolites in plasma collected during Phase I clinical trials. Furthermore, the assay values were compared with those determined by the radioimmunoassay method, which has been routinely used to determine olopatadine in plasma.     

Quantification of ceramide species in biological samples by liquid chromatography electrospray ionization tandem mass spectrometry

We present an optimized and validated liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method for the simultaneous measurement of concentrations of different ceramide species in biological samples. The method of analysis of tissue samples is based on Bligh and Dyer extraction, reverse-phase high-performance liquid chromatography separation, and multiple reaction monitoring of ceramides. Preparation of plasma samples also requires isolation of sphingolipids by silica gel column chromatography prior to LC-ESI-MS/MS analysis. The limits of quantification were in a range of 0.01-0.50 ng/ml for distinct ceramides. The method was reliable for inter- and intraassay precision, accuracy, and linearity. Recoveries of ceramide subspecies from human plasma, rat liver, and muscle tissue were 78 to 91%, 70 to 99%, and 71 to 95%, respectively. The separation and quantification of several endogenous long-chain and very-long-chain ceramides using two nonphysiological odd chain ceramide (C17 and C25) internal standards was achieved within a single 21-min chromatographic run. The technique was applied to quantify distinct ceramide species in different rat tissues (muscle, liver, and heart) and in human plasma. Using this analytical technique, we demonstrated that a clinical exercise training intervention reduces the levels of ceramides in plasma of obese adults. This technique could be extended for quantification of other ceramides and sphingolipids with no significant modification.