Naveen Sharma

An accurate, rapid and sensitive determination of tramadol and its active metabolite O-desmethyltramadol in human plasma by LC-MS/MS.

A rapid, sensitive and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for the simultaneous determination of tramadol and its active metabolite, O-desmethyltramadol in human plasma is developed using propranolol as internal standard (IS). The analytes and IS were extracted from 200 microL aliquots of human plasma via protein precipitation using acetonitrile. Chromatographic separation was achieved in a run time of 2.0 min on an Aquasil C18 (100mm x 2.1mm, 5microm) column under isocratic conditions. Detection of analytes and IS was done by tandem mass spectrometry, operating in positive ion and multiple reaction monitoring (MRM) acquisition mode. The method was fully validated for its selectivity, sensitivity, linearity, precision and accuracy, recovery, matrix effect, ion suppression/enhancement, stability and dilution integrity. A linear dynamic range was established from 1.0 to 600.0ng/mL for tramadol and 0.5-300.0ng/mL for O-desmethyltramadol. The method was successfully applied to a bioequivalence study of 200mg tramadol tablet formulation in 27 healthy Indian male subjects under fasting condition.

Liquid chromatography tandem mass spectrometry assay for the simultaneous determination of venlafaxine and O-desmethylvenlafaxine in human plasma and its application to a bioequivalence study

A rapid, simple and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for simultaneous determination of venlafaxine (VEN) and its active metabolite, O-desmethylvenlafaxine (ODV) in human plasma was developed using nadolol as internal standard (IS). The analytes and IS were extracted from 200 microl aliquots of human plasma via protein precipitation using 0.43% formic acid in acetonitrile and separated on a Hypurity cyano (50 mm x 4.6 mm, 5 microm) column. Quantitation was performed on a triple quadrupole mass spectrometer employing electrospray ionization technique, operating in multiple reaction monitoring (MRM) and positive ion mode. The precursor to product ion transitions monitored for VEN, ODV and IS were m/z 278.3-->58.1, 264.3-->58.1 and 310.4-->254.1, respectively. The total chromatographic runtime was 3 min with retention time for VEN, ODV and IS at 1.93, 1.50 and 1.29 min, respectively. The method was fully validated for its sensitivity, accuracy and precision, linearity, recovery, matrix effect, dilution integrity and stability studies. The linear dynamic range of 2.0-500 ng/ml was established for both VEN and ODV with mean correlation coefficient (r), 0.9994 and 0.9990, respectively. The intra-batch and inter-batch precision (%CV) in three validation batches across five concentration levels (LLOQ, LQC, MQC, HQC and ULOQ) was less than 12.6% for both the analytes. The accuracy determined at these levels was within -9.8 to +3.9% in terms of %bias. The method was successfully applied to a bioequivalence study of 150 mg venlafaxine extended release capsule formulation in 22 healthy Indian male subjects under fed condition.

High throughput and sensitive determination of trazodone and its primary metabolite, m-chlorophenylpiperazine, in human plasma by liquid chromatography–tandem mass spectrometry

A precise, sensitive and high throughput liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of trazodone (TRZ) and its primary metabolite, m-chlorophenylpiperazine (mCPP), in human plasma was developed and validated. The analytes and the internal standard-nefazodone were extracted from 500 microL aliquots of human plasma via liquid-liquid extraction in n-hexane. Chromatographic separation was achieved in a run time of 2.5 min on a Betabasic cyano column (100 mm x 2.1 mm, 5 microm) under isocratic conditions. Detection of analytes and IS was done by tandem mass spectrometry, operating in positive ion and multiple reaction monitoring (MRM) acquisition mode. The protonated precursor to product ion transitions monitored for TRZ, mCPP and IS were m/z 372.2-->176.2, 197.2-->118.1 and 470.5-->274.6 respectively. The method was fully validated for its sensitivity, selectivity, accuracy and precision, matrix effect, stability study and dilution integrity. A linear dynamic range of 10.0-3000.0 ng/mL for TRZ and 0.2-60.0 ng/mL for mCPP was evaluated with mean correlation coefficient (r) of 0.9986 and 0.9990 respectively. The intra-batch and inter-batch precision (%CV) across five validation runs (LLOQ, lower limit of quantitation; LQC, low quality control; MQC, middle quality control; HQC, high quality control and ULOQ, upper limit of quantitation) was < or =8.4% for both the analytes. The method was successfully applied to a bioequivalence study of 100mg trazodone tablet formulation in 36 healthy Indian male subjects under fasting and fed conditions.

Analysis of second-generation antidepressant drug, sertraline and its active metabolite, N-desmethyl sertraline in human plasma by a sensitive and selective liquid chromatography–tandem mass spectrometry method

A precise, sensitive and high throughput liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of sertraline (SER) and its primary metabolite, N-desmethyl sertraline (NDS) in human plasma is developed and validated. The analytes and the internal standard-fluoxetine were extracted from 300 microL aliquots of human plasma via liquid-liquid extraction in methyl tert-butyl ether. Chromatographic separation was achieved in a run time of 2.5 min on a Betasil C8 column (100 mm x 2 .1 mm, 5 microm) under isocratic conditions. Detection of analytes and IS was done by tandem mass spectrometry, operating in positive ion and multiple reaction monitoring (MRM) acquisition mode. The protonated precursor to product ion transitions monitored for SER, NDS and IS were m/z 306.2-->159.0, 292.1-->159.0 and 310.6-->148.4, respectively. The method was fully validated for its sensitivity, selectivity, linearity, accuracy and precision, matrix effect, stability study and dilution integrity. A linear dynamic range of 0.5-150 ng/mL was established for both the analytes with mean correlation coefficient (r) of 0.9993 and 0.9980, respectively. The intra-batch and inter-batch precision (%CV) across five quality control levels was <or=10.4% for both the analytes. The method was successfully applied to a bioequivalence study of 100mg sertraline tablet formulation in 32 healthy Indian male subjects under fasting condition.

Simultaneous determination of simvastatin and simvastatin acid in human plasma by LC-MS/MS without polarity switch: application to a bioequivalence study.

A simple, specific and sensitive LC-MS/MS assay for simultaneous determination of simvastatin (SV) and its active beta-hydroxy acid metabolite, simvastatin acid (SVA) in human plasma was developed using a statin analog as internal standard (IS). The method was validated over a dynamic linear range of 0.20-100.00 ng/mL for SV and 0.10-50.00 ng/mL for SVA with correlation coefficient r > or = 0.9987 and 0.9989, respectively. The analytes and IS were extracted from 500 microL aliquots of human plasma via liquid-liquid extraction using methyl tert-butyl ether and separated through an Aquasil C18 column (100 mm x 2.1 mm, 5 microm). Detection of analytes and IS was done by MS/MS with a turbo ion spray interface operating in positive ion and selective reaction monitoring acquisition mode. The total chromatographic run time was 3.0 min. Flash freezing of the aqueous phase was an added advantage during liquid-liquid extraction, which considerably reduced time and labour. The method was extensively validated for its accuracy, precision, recovery, stability studies and matrix effect. The method was successfully used for bioequivalence study of 40 mg SV tablet formulation in 12 human subjects under fasting condition.

Quantitation of donepezil and its active metabolite 6-O-desmethyl donepezil in human plasma by a selective and sensitive liquid chromatography–tandem mass spectrometric method

A sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for the simultaneous determination of donepezil (D) and its pharmacologically active metabolite, 6-O-desmethyl donepezil (6-ODD) in human plasma is developed using galantamine as internal standard (IS). The analytes and IS were extracted from 500 microL aliquots of human plasma via solid-phase extraction (SPE) on Waters Oasis HLB cartridges. Chromatographic separation was achieved in a run time of 6.0 min on a Waters Novapak C18 (150 mm x 3.9 mm, 4 microm) column under isocratic conditions. Detection of analytes and IS was done by tandem mass spectrometry, operating in positive ion and multiple reaction monitoring (MRM) acquisition mode. The protonated precursor to product ion transitions monitored for D, 6-ODD and IS were at m/z 380.1-->91.2, 366.3-->91.3 and 288.2-->213.2, respectively. The method was fully validated for its selectivity, interference check, sensitivity, linearity, precision and accuracy, recovery, matrix effect, ion suppression/enhancement, cross-specificity, stability and dilution integrity. A linear dynamic range of 0.10-50.0 ng mL(-1) for D and 0.02-10.0 ng mL(-1) for 6-ODD was evaluated with mean correlation coefficient (r) of 0.9975 and 0.9985, respectively. The intra-batch and inter-batch precision (%CV, coefficient of variation) across five quality control levels was less than 7.5% for both the analytes. The method was successfully applied to a bioequivalence study of 10mg donepezil tablet formulation in 24 healthy Indian male subjects under fasting condition.

Development and validation of a selective and sensitive LC–MS/MS method for determination of cycloserine in human plasma: Application to bioequivalence study

A selective and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for the determination of cycloserine in human plasma is developed using niacin as internal standard (IS). The analyte and IS were extracted from 500 μL of human plasma via solid phase extraction on Waters Oasis MCX cartridges. Chromatographic separation was achieved on a Peerless Basic C18 (100 mm × 4.6mm, 3 μm) column under isocratic conditions. Detection of analyte and IS was done by tandem mass spectrometry, operating in positive ion and multiple reaction monitoring (MRM) acquisition mode. The protonated precursor to product ion transitions monitored for cycloserine and niacin were at m/z 103.1 → 75.0 and 124.1 → 80.1 respectively. The method was fully validated for its selectivity, interference check, sensitivity, carryover check, linearity, precision and accuracy, reinjection reproducibility, recovery, matrix effect, ion suppression/enhancement, stability and dilution integrity. The limit of detection (LOD) and lower limit of quantitation of the method were 0.0013 and 0.20 μg/mL respectively with a linear dynamic range of 0.20-30.00 μg/mL for cycloserine. The intra-batch and inter-batch precision (%CV) across six quality control levels was less than 8.0% for cycloserine. The method was successfully applied to a bioequivalence study of 250 mg cycloserine capsule formulation in 24 healthy Indian male subjects under fasting condition.

High-throughput LC-MS/MS assay for 6-methoxy-2-naphthylacetic acid, an active metabolite of nabumetone in human plasma and its application to bioequivalence study

A simple, precise and accurate assay for the determination of 6-methoxy-2-naphthylacetic acid (6-MNA), an active metabolite of nabumetone in human plasma, was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The analyte (6-MNA) and propranolol (internal standard, IS) were extracted from 200 microL aliquot of human plasma via solid-phase extraction employing HLB Oasis cartridges and separated on a Discovery HS C18 (50 x 4.6 mm, 5 microm) column. Detection of analyte and IS was done by tandem mass spectrometry with a turbo ion spray interface operating in positive ion and multiple reaction monitoring acquisition mode. The total chromatographic runtime was 3.0 min with retention time for 6-MNA and IS at 1.97 and 1.26 min, respectively. The method was validated over a dynamic linear range of 0.20-60.00 microg/mL for 6-MNA with mean correlation coefficient r > or = 0.9986. The intra-batch and inter-batch precision (%CV) across five validation runs (lower limit of quantiation, low-, medium- and high-quality controls and upper limit of quantitation) was less than 7.5%. The accuracy determined at these levels was within -5.8 to +0.2% in terms of percentage bias. The method was successfully applied for a bioequivalence study of 750 mg nabumetone tablet formulation in 12 healthy Indian male subjects under fasted condition.

Application of a rapid and sensitive liquid chromatography–tandem mass spectrometry method for determination of bumetanide in human plasma for a bioequivalence study

A rapid, selective and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay has been proposed for the determination of bumetanide in human plasma using tamsulosin as internal standard (IS). The analyte and IS were extracted from 200 μL of human plasma via solid phase extraction and the chromatographic separation was achieved on Peerless Basic C18 (100 mm × 4.6 mm, 3 μm) column under isocratic conditions. Detection of bumetanide and IS was done by tandem mass spectrometry, operating in positive ionization and multiple reaction monitoring (MRM) acquisition mode. The protonated precursor to product ion transitions monitored for bumetanide and IS were m/z 365.2→240.2 and 409.2→228.2 respectively. The method was fully validated as per the US FDA guidelines. The limit of detection and lower limit of quantitation of the method were 0.03 and 0.30 ng/mL respectively with a linear dynamic range of 0.30-200.0 ng/mL for bumetanide. The intra-batch and inter-batch precision (% CV) was ≤6.9% while the mean extraction recovery was >90% across quality control levels. The method is selective in presence of four diuretic drugs and some commonly used medications by healthy volunteers. It was successfully applied to a bioequivalence study of 2mg bumetanide tablet formulation in 10 healthy Indian male subjects under fasting condition. The reproducibility in the measurement of study data was demonstrated by reanalysis of 42 incurred samples.

Analysis of a second-generation tetracycline antibiotic minocycline in human plasma by LC–MS/MS

A simple, selective and sensitive LC-MS/MS assay has been developed for the determination of minocycline in human plasma. Plasma samples were prepared by protein precipitation, followed by chromatographic separation on a HyPURITY™ C8 (100 mm × 4.6 mm, 5 µm) column under isocratic conditions. The LOD and LLOQ of the method were 0.50 and 20.0 ng/ml, respectively. The intra-batch and inter-batch precision (% coefficient of variation) across quality control levels was less than 8.0%. For a set of incurred samples the percentage change in concentration was within ± 9.0%. The method was successfully applied to a bioequivalence study of 135 mg minocycline tablet formulation in 14 healthy Indian males. The reproducibility in the measurement of study data was demonstrated by incurred sample reanalysis.