Quantification of faropenem in human plasma by high-performance liquid chromatography

A simple, sensitive and specific high-performance liquid chromatography (HPLC) method with ultraviolet detection (315 nm) was developed and validated for quantitation of faropenem (CAS 106560-14-9), the newest addition to the group of beta-lactam antimicrobials, in human plasma. Following solid-phase extraction using Waters Oasis SPE cartridges, the analyte and internal standard (hydrochlorothiazide, CAS 58-93-5) were separated using an isocratic mobile phase of 10 mmol/L acetate buffer (pH adjusted to 7.0 with dilute acetic acid) / methanol / triethyl amine (70/30/0.03, v/v/v) on reverse phase Waters symmetry C18 column. The lower limit of quantitation was 200 ng/mL, with a relative standard deviation of less than 2 %. A linear range of 200 to 25000 ng/mL was established. This HPLC method was validated with between-batch and within-batch precision of 1.6 to 2.3 % and 0.4 to 1.6 %, respectively. The between-batch and within-batch bias was -3.1 to 5.3 % and -6.0 to 1.5 %, respectively. Frequently coadministered drugs did not interfere with the described methodology. The stability of faropenem in plasma was excellent, with no evidence of degradation during sample processing (autosampler) and 30 days storage in a freezer. This validated method is sensitive, simple and repeatable enough to be used in pharmacokinetic studies.     

Quantification of oxcarbazeipine and its active metabolite 10-hydroxycarbazepine in human plasma by high-performance liquid chromatography

A simple, sensitive and selective high-performance liquid chromatography (HPLC) method with ultraviolet detection (230 nm) was developed and validated for the quantification of oxcarbazepine (CAS 28721-07-5), a new antiepileptic drug, and its active metabolite 10-hydroxycarbazepine (CAS 29331-92-8) in human plasma. Following solid-phase extraction, the analytes and internal standard (zaleplon, CAS 151319-34-5) were separated using an isocratic mobile phase on a reverse phase C18 column. The lower limit of quantification was 50 ng/mL for oxcarbazepine and 100 ng/mL for 10-hydroxycarbazepine with a relative standard deviation of less than 10%. A linear dynamic range of 50 to 5000 ng/mL for oxcarbazepine and of 100 to 10000 ng/mL for 10-hydroxycarbazepine was established. This HPLC method was validated with between-batch precision of 0.8 to 8.6% and 3.2 to 7.5% for oxcarbazepine and 10-hydroxycarbazepine respectively. The between-batch accuracy was 94.0 to 102.4% and 95.4 to 105.6%, respectively. Stability of oxcarbazepine and 10-hydroxycarbazepine in plasma was excellent, with no evidence of degradation during sample processing (autosampler) and 30 days storage in a freezer. This validated method is sensitive, simple and repeatable enough to be used in pharmacokinetic studies.     

Simultaneous quantification of three alkaloids of Coptidis Rhizoma in rat urine by high-performance liquid chromatography: application to pharmacokinetic study

A high-performance liquid chromatographic method with ultraviolet detection was established and validated for quantification of three alkaloids (coptisine, palmatine and berberine) in rat urine. Following a single-step liquid-liquid extraction, the analytes were separated on a reversed-phase C(18) column with water-formic acid-triethylamine-methanol as the mobile phase at a flow rate of 1 ml/min. The linear ranges of the calibration curves were 1.6-160 ng/ml for all three alkaloids. The lower limit of quantification was 1.6 ng/ml for all three alkaloids. The within-batch accuracy was 90.4-108.3% for coptisine, 88.6-107.8% for berberine and 88.4-110.1% for palmatine. The between-batch accuracy was 99.3-100.3% for coptisine, 94.3-100.6% for berberine and 93.7-100.0% for palmatine. The within-batch and between-batch precisions were 相似文献   

A simple and sensitive liquid chromatography method for the determination of low dihydrocodeine concentrations in human plasma: its application in Chinese healthy volunteers

A simple, sensitive and modified method was developed for determination of low dihydrocodeine (CAS 125-28-0) concentrations in human plasma by high performance-liquid chromatography (HPLC) with diode array detector. Measurement was performed on a Zorbax XDB-C18 analytical column together with a XDB-C18 precolumn at 40 degrees C after a simple one-step extraction. An isocratic mobile phase consisting of acetonitrile-0.1% trifluoroacetic acid (TFA)-water (12:40:48, v/v/v), was run at a flow rate of 1.0 mL/min. Good chromatographic separation was achieved in less than 6.2 min. This assay was linear over a concentration range of 2.50-100 ng/mL with a lower limit of quantification at 2.50 ng/mL. The intra- and inter-day precision (relative standard deviation) was less than 6.00 and 6.62%, respectively, at all concentration levels studied, while the intra- and inter-day accuracy was 1.50-3.73% and -1.35-1.92%, respectively. Recoveries were 76.10-83.81% with coefficients of variation of 1.86-6.93%. Stability of dihydrocodeine in plasma proved to be good. The validated method was successfully applied to a bioequivalence study of dihydrocodeine after a single oral administration of 20 mg dihydrocodeine tartrate in Chinese healthy male volunteers.     

Bioanalytical method development, validation and quantification of flupirtine maleate in rat plasma by liquid chromatography-tandem mass spectrometry

A simple, highly sensitive, precise and accurate high-performance liquid chromatographic (LCMSMS) method with mass detection was developed and validated for the rapid quantification of flupirtine (CAS 75507-68-5) in rat plasma samples. The chromatographic separation was achieved with a reverse phase column (4.6 x 50 mm, 5 microm) and the mobile phase consisted of cyanomethane and 5 mM ammonium formate buffer pH 4.5 (70:30 v/v) as eluent, at a flow rate of 0.6 mL/min. Labetalol (CAS 36894-69-6) was used as an internal standard. The effluence was ionized by positive electrospray ionization and measured by mass spectrometry. The retention times of flupirtine and labetalol were found to be 2.16 and 1.66 min respectively. The calibration curve was linear (r2 > or = 0.99) ranging from 0.98 to 1000 ng/ml and the lower limit of quantification was 0.98 ng/ mL. Inter-day and Intra-day precision were lower than 5% (CV) and accuracy ranged from 90 to 110% in terms of percent accuracy. Mean extraction recovery was found to be above 86.5%. The method was successfully applied for evaluation of the pharmacokinetic profile of flupirtine in male Sprague-Dawley rats and validated for excellent selectivity, accuracy, precision, recovery and stability.     

Fluorimetric determination of rivastigmine in rat plasma by a reverse phase--high performance liquid chromatographic method. Application to a pharmacokinetic study

A sensitive and selective high performance liquid chromatographic (HPLC) method was developed and validated for the rapid quantification of rivastigmine (CAS 123441-03-2) in micro quantity in rat plasma samples. The chromatographic separation was achieved with a reverse phase monomeric column C18 (4.6 x 250 mm, 5 microm) and the mobile phase consisted of acetonitrile and 20 mmol/L phosphate buffer pH 3.0 (25:75) with a flow rate of 1 mL/min. The effluents were measured by fluorimetric detection with excitation and emission wavelengths at 220 nm and 293 nm, respectively. The calibration curve was linear (r2 > 0.99) ranging from 25-3000 ng/mL and the lower limit of quantification was 25 ng/mL. The method was validated with excellent sensitivity, selectivity, accuracy, precision, recovery and stability. The method has been successfully applied in a pharmacokinetic study of rivastigmine in rats.     

HPLC-UV determination of morphine in human plasma and its application to the clinical study

A sensitive and specific high-performance liquid chromatography method with ultraviolet detection (HPLC-UV) has been developed for the quantification of morphine sulfate [(5alpha,6alpha)-7,8-didehydro-4,5-epoxy-17-methylmorphinan-3,6-diol], (CAS: 52-26-6) in human plasma. The analyte was extracted from plasma samples with chloroform - isopropyl alcohol (90:10, v/v) and analyzed on a Bondapak C18 column. The calibration curves were linear within the range of 10-150 ng/mL. The lower limit of quantitation was 10 ng/mL with 0.5 mL plasma sample. The mean recovery of the drug from plasma samples was 83.39%. The results from analysis of quality-control samples at concentrations of 30, 75, and 150 ng/mL were indicative of good accuracy and precision. This method was successfully used to analyze morphine in plasma samples of patients after abdominal hysterectomy.     

Determination of cetirizine in human plasma using high performance liquid chromatography coupled with tandem mass spectrometric detection: application to a bioequivalence study

A rapid, sensitive and selective HPLC-MS/ MS method was developed and validated for the quantification of cetirizine dihydrochloride (CAS 83881-51-0) in human plasma using mosapride citrate as internal standard (IS, CAS 112885-42-4). Following liquid-liquid extraction, the analytes were separated using a mobile phase consisting of methanol and aqueous ammonium acetate solution (10 mM) (60:40, v/v) on a reverse phase C18 column and analyzed by a triple-quadrupole mass spectrometer in the selected reaction monitoring (SRM) mode using the respective [M+H]+ ions, m/z 398 --> 201 for cetirizine and m/z 422 --> 198 for mosapride. The analysis time for each run was 8.0 min. The assay exhibited a linear dynamic range of 0.5-500 ng/ml for cetirizine dihydrochloride in human plasma. The lower limit of quantification (LLOQ) was 0.5 ng/ml with a relative standard deviation of less than 15% (all the concentration data in this study related to the salt (cetirizine dihydrochloride)). Acceptable precision and accuracy were obtained for concentrations over the standard curve range. It is the first time that the validated HPLC-MS/MS method has been successfully applied to a bioequivalence study in 20 healthy male Chinese volunteers.     

RP—HPLC法测定人血浆中头孢妥仑的含量

目的建立了RP-HPLC法测定人血浆中头孢妥仑的浓度。方法色谱柱Nucleodur C18分析柱（4．6mm×250mm 5μm）,流动相为0．03％三氟乙酸缓冲液／乙腈（81／19,V／V）,流速1．0ml／min,检测波长为305nm,柱温30℃,取上清液直接进样,进样量为20μL结果头孢妥仑线性范围为0．02～5．01μg／mL。头孢妥仑的最低检测限为0．02μg／mL,日内、日间RSD均小于5％,相对回收率为97．6％-104．5％,提取回收率均大于91．3％。结论这种验证方法灵敏、简便、可重复,足以用于药代动力学研究。     

Determination of domperidone in human plasma using liquid chromatography coupled to tandem mass spectrometry and its pharmacokinetic study

A sensitive and selective liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of domperidone (CAS number: 57808-66-9) in human plasma using paracetamol (CAS number: 103-90-2) as an internal standard (IS). Domperidone and paracetamol in plasma were extracted with ethyl acetate, separated on a C18 reversed phase column, eluted with mobile phase of acetonitrile-glacial acetic acid (0.3%) (40:60, v/v), ionized by positive ion pneumatically assisted electrospray and detected in the multi-reaction monitoring mode using precursor→product ions of m/z 426.2→175.1 for domperidone and 152→110 for the IS, respectively. The calibration curve was linear (r2≥0.99, n=5) over the concentration range of 0.2-80 ng/mL and with lower limit of detection and quantitation of 0.05 and 0.2 ng/mL. The speci?city, matrix effect, recovery, sensitivity, linearity, accuracy, precision, and stabilities were validated for domperidone in human plasma. In conclusion, the validation results showed that this method was sensitive, economical and less toxic and it can successfully ful?ll the requirement of clinical pharmacokinetic study of domperidone oral preparation in Chinese healthy volunteers.     

A rapid high-performance liquid chromatographic method for the determination of pantoprazole in plasma using UV detection. Application in pharmacokinetic studies

A rapid, sensitive and reproducible HPLC method was developed and validated for the analysis of pantoprazole (CAS 102625-70-7) in human plasma. The separation was achieved on a monolithic silica column using acetonitrile-potassium dihydrogen phosphate buffer (25:75,v/v), pH 3.0, as the mobile phase at a flow rate of 1.5 ml min(-1). The wavelength was set at 290 nm. The assay enables the measurement of pantoprazole for therapeutic drug monitoring with a minimum quantification limit of 20 ng ml(-1). The method involves a simple protein precipitation procedure. Analyticil recovery was complete. The calibration curve was linear over the concentration range 20-3500 ng ml(-1) The coefficients of variation forthe inter-day and intra-day assay were found to be less than 7%.     

Column-switching high-performance liquid chromatographic analysis of fluvastatin in rat plasma by direct injection

A column-switching high-performance liquid chromatographic (HPLC) method has been developed and validated for quantification of fluvastatin in rat plasma. Plasma samples were diluted with an equal volume of mobile phase, i.e. acetonitrile-5 mM potassium phosphate buffer (pH 6.8) (15:85, v/v), and the mixture was directly injected onto the HPLC system. The analyte was enriched in a pre-treatment column, while endogenous components were eluted to waste. The analyte was then back-flushed onto an analytical column and quantified with fluorescence detection (lambdaex=305 nm; lambdaem=390 nm). The standard curve for the drug was linear in the range 0.5-100 ng mL(-1) in rat plasma. The limit of quantitation for plasma was found to be 0.5 ng mL(-1). This method has been fully validated and shown to be specific, accurate and precise. The method is simple and rapid because of a minimized sample preparation and appears to be useful for the pharmacokinetic study of fluvastatin.     

HPLC determination of omeprazole in human plasma using a monolithic column

A rapid and sensitive HPLC method using a monolithic column has been developed for quantification of omeprazole (CAS 73590-58-6) in plasma. The method was specific and sensitive with a quantification limit of 10 ng/ml. Sample preparation involves simple, one-step extraction procedure and analytical recovery was complete. The separation was carried out in reversed-phase conditions using a Chromolith Performance (RP-18e, 100 x 4.6 mm) column with an isocratic mobile phase consisting of 0.01 mol/l disodium hydrogen phosphate buffer-acetonitrile (73:27 v/v) adjusted to pH 7.1. The wavelength was set at 302 nm. The calibration curve was linear over the concentration range 20-1500 ng x ml(-1). The coefficients of variation for inter-day and intra-day assay were found to be less than 7%.     

Simple and sensitive liquid chromatography–tandem mass spectrometry methods for quantification of tadalafil in rat plasma: application to pharmacokinetic study in rats

A simple and sensitive liquid chromatography–tandem mass spectrometry method was developed and validated in rat plasma for quantification of tadalafil, a novel therapeutic agent for erectile dysfunction. Tadalafil and acebutolol (internal standard) were extracted by liquid–liquid extraction with tert-butyl methyl ether. The chromatographic separation was performed on a reverse phase C₁₈ column with a mobile phase consisting of 0.1 % formic acid and acetonitrile (45:55, v/v) at a flow rate of 0.3 mL/min. The protonated analyte was quantitated by multiple reaction monitoring with a Waters Quattro micro? API mass spectrometer. The calibration curve was linear over a concentration range of 2–2000 ng/mL, and the lower limit of quantification was 2 ng/mL with a precision (CV %) of 10.9 %. Acceptable intra-day and inter-day precision and accuracy were obtained at 3 concentration levels (3, 200, and 1500 ng/mL). Tadalafil was found to be stable in a battery of studies, including bench top, freeze–thaw, and autosampler conditions. The validated method was successfully used to determine tadalafil concentration in rat plasma samples after oral administration at a dose of 1 mg/kg.     

Quantification of voriconazole in human plasma by high-performance liquid chromatography-electrospray ionization mass spectrometry: application to a bioequivalence study

A sensitive and specific liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method was developed and validated for the identification and quantification of voriconazole (VRC, CAS 137234-62-9) in human plasma. Following liquid-liquid extraction, VRC and loratadine (internal standard, CAS 79794-75-5) were separated using a mobile phase comprised of methanol: water (0.1% formic acid) = 75:25 v/v on a Shimadzu Shim-pack VP-ODS C18 (150 x 2.0 mm ID, 5 microm) column and analyzed by electrospray ionization mass spectrometry. The chromatographic separation was achieved in less than 6 min. The standard curves were linear (r = 0.9994) over the concentration range of 2-2000 ng/mL for VRC and had good accuracy and precision. Both intra- and inter-batch standard deviations were less than 15%. The method was successfully applied to study the comparative bioavailability of VRC tablets test vs. reference in healthy Chinese volunteers through the statistical comparison of pharmacokinetic parameters obtained with the two formulations.     

Development of a sensitive size exclusion HPLC method with fluorescence detection for the quantitation of recombinant human erythropoietin (r-HuEPO) aggregates

Human erythropoietin produced by recombinant DNA technology, is now marketed worldwide for the treatment of anemias associated with chronic renal failure and chemotherapy. No sensitive methods, which can determine r-HuEPO dimer or oligomer aggregate content in formulated products, have been published to date. This report describes the development and validation of a sensitive size exclusion high performance liquid chromatography (HPLC) method for the quantitation of r-HuEPO aggregates in formulations containing 0.03% polysorbate 80. A Waters Alliance 2690 HPLC system connected to a TosoHaas TSKgel G3000 SWxl (7.8 mm x 30 cm, 250 A pore size, 5 microm particle size) column and a Waters 474 fluorescence detector was used. The mobile phase for the SEC-HPLC method consists of isopropyl alcohol-potassium phosphate (0.1 M)/potassium chloride buffer (pH 6.8+/-0.1, 0.2 M) (25:75, v/v). The flow rate was 0.3 mL/min and the method run time was 60 min. The SEC-HPLC method presented here was shown to be specific for r-HuEPO total aggregates (dimer and oligomers) and allows for their quantitation at 80 ng/mL or 4 ngs/injection, in the presence of r-HuEPO monomer and the pharmaceutical excipients, glycine (5 mg/mL), sodium chloride (4.3 mg/mL), and 0.03% polysorbate 80. The finalized method is stability-indicating and is suitable for determining r-HuEPO aggregates between 0.2 and 0.5% levels in the formulated product of r-HuEPO. This method offers a robust way to measure total aggregates on a routine basis with a high sensitivity for use in product quality control.     

High-performance liquid chromatographic analysis of the anticancer drug irinotecan (CPT-11) and its active metabolite SN-38 in human plasma

A rapid, sensitive, and specific high-performance liquid chromatography (HPLC) method for the simultaneous determination of irinotecan (CPT-11) and its active metabolite SN-38 in human plasma is described. The analytes are quantified as the totals of their carboxylate and lactone form. The sample pretreatment consisted of a simple protein precipitation with acetonitrile-methanol (1:1, v/v), after which CPT-11 and SN-38 were quantitatively converted to their carboxylate form by adding 0.01 mol/L sodium tetraborate (pH, 9). Chromatography was carried out on a Zorbax SB-C18 column with fluorescence detection. The method has been validated, and stability tests under various clinically relevant conditions have been performed. The lower limit of quantification (LLOQ) was 5.0 ng/mL for CPT-11 and 0.5 ng/mL for SN-38. Standard concentration ranges were linear between 5 and 1,500 ng/mL for CPT-11 and between 0.5 and 100 ng/mL for SN-38. This assay is simple, rapid, and very useful for therapeutic monitoring of CPT-11 and SN-38.     

Sensitive and robust UPLC-MS/MS method to determine the gender-dependent pharmacokinetics in rats of emodin and its glucuronide

A sensitive and simple liquid chromatography-mass spectrometry (LC-MS) method has been developed and validated for the quantification of solamargine, a steroidal glycoalkaloid, in rat plasma. Vincristine was selected as the internal standard. Sample preparation involved simple liquid-liquid extraction by ethyl acetate with high efficiency. The chromatographical separation was performed on a Shimadzu C(18) column (150mm×2.0mm, 5μm) with a gradient elution of acetonitrile and 0.02% (v/v) formic acid. The elutes were detected under positive electrospray ionization (ESI) and the target analytes quantified by selected ion monitoring (SIM) mode. The method was sensitive with the lowest limit of quantitation (LLOQ) at 0.5ng/mL in 50μL of rat plasma. Good linearity (r(2)=0.9996) was obtained covering the concentration of 0.5-2000.0ng/mL. The intra- and inter-day assay precision ranged from 2.87 to 3.60% and 0.52 to 6.81%, respectively. In addition, the stability, extraction recovery and matrix effect involved in the method were also validated. The practical utility of the aforementioned method was successfully confirmed in the pharmacokinetic evaluation of solamargine in Sprague-Dawley rats after intravenous administration.     

Simultaneous quantification of triazolam and its metabolites in human urine by liquid chromatography-tandem mass spectrometry

A simple, simultaneous, sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS-MS) method for the determination of triazolam and its metabolites, α-hydroxytriazolam (α-OHTRZ) and 4-hydroxytriazolam (4-OHTRZ), in human urine was developed and validated. Triazolam-d4 was used as the internal standard (IS). This analysis was carried out on a Thermo(?) C(18) column, and the mobile phase was composed of acetonitrile/H(2)O/formic acid (35:65:0.2, v/v/v). Detection was performed on a triple-quadrupole tandem MS using positive ion mode electrospray ionization, and quantification was performed by multiple reaction monitoring mode. The MS-MS ion transitions monitored were m/z 343.1 → 308.3, 359.0 → 331.0, 359.0 → 111.2, and 347.0 → 312.0 for triazolam, α-OHTRZ, 4-OHTRZ, and triazolam-d(4), respectively. The lower limits of quantification of the analytical method were 0.5 ng/mL for triazolam, 5 ng/mL for α-OHTRZ, and 0.5 ng/mL for 4-OHTRZ. The within- and between-run precisions were less than 15%, and accuracy was -12.33% to 9.76%. The method was proved to be accurate and specific, and it was applied to a urinary excretion study of triazolam in healthy Chinese volunteers.     

Determination of strychnine and brucine in rat plasma using liquid chromatography electrospray ionization mass spectrometry

A simple, sensitive and selective liquid chromatography–electrospray mass spectrometric (LC–ESI-MS) method was developed and validated for simultaneous determination of strychnine and brucine in rat plasma, using tacrine as the internal standard (IS). Sample preparation involved a liquid–liquid extraction of the analytes with n-hexane, dichloromethane and isopropanol (65:30:5, v/v/v) from 0.1 mL of plasma. Chromatographic separation was carried out on a Waters C₁₈ column using a mobile phase of methanol–20 mM ammonium formate–formic acid (32:68:0.68, v/v/v). Positive selected ion monitoring mode was used for detection of strychnine, brucine and the IS at m/z 335.2, m/z 395.2 and m/z 199.2, respectively. Linearity was obtained over the concentration range of 0.5–500 ng/mL for strychnine and 0.1–100 ng/mL for brucine. The lower limit of quantification was 0.5 ng/mL and 0.1 ng/mL for strychnine and brucine, respectively. The intra- and inter-day precision for both strychnine and brucine was less than 7.74%, and accuracy ranged from −4.38% to 2.21% at all QC levels. The method has been successfully applied to a pharmacokinetic study of processed Semen Strychni after oral administration to rats.