Enantioselective determination of (R)‐ and (S)‐lansoprazole in human plasma by chiral liquid chromatography with mass spectrometry and its application to a stereoselective pharmacokinetic study

A simple and enantioselective method was developed and validated for the simultaneous determination of (R)‐ and (S)‐lansoprazole in human plasma by chiral liquid chromatography with tandem mass spectrometry. Lansoprazole enantiomers and internal standard (esomeprazole) were extracted from plasma using acetonitrile as protein precipitating agent. Baseline chiral separation was achieved within 9.0 min on a Chiralpak IC column (150 mm × 4.6 mm, 5 μm) with the column temperature of 30°C. The mobile phase consisted of 10 mM ammonium acetate solution containing 0.05% acetic acid/acetonitrile (50:50, v/v). The mass spectrometric analysis was performed using a QTrap 5500 mass spectrometer coupled with an electrospray ionization source in positive ion mode. The multiple reactions monitoring transitions of m/z 370.1→252.1 and 346.1→198.1 were used to quantify lansoprazole enantiomers and esomeprazole, respectively. For each enantiomer, no apparent matrix effect was found, the calibration curve was linear over 5.00–3000 ng/mL, the intra‐ and inter‐day precisions were below 10.0%, and the accuracy was –3.8 to 3.3%. Analytes were stable during the study. No chiral inversion was observed during sample storage, preparation procedure and analysis. The method was applied to the stereoselective pharmacokinetic studies in human after intravenous administration of dexlansoprazole or racemic lansoprazole.     

Determination of the (+)- and (-)-enantiomers of pirprofen in human plasma by high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) method was developed to determine the (+)- and (-)-enantiomers of pirprofen, an anti-inflammatory drug. After addition of an internal standard, the plasma sample was brought onto a glass column pre-packed with silica and eluted with dichloromethane. The extracts were derivatized with 1,1'-carbonyldiimidazole and R (+)-1-methylbenzylamine to form the two diastereomeric amides. The diastereoisomers were separated on a chiral column by HPLC with ultraviolet detection at 272 nm using n-hexane-dichloromethane (64:36, v/v) as the mobile phase. The limit of quantitation was 0.992 mumol/l (0.25 microgram/ml) for each enantiomer.     

Determination of darusentan enantiomers in rat plasma by enantioselective liquid chromatography with tandem mass spectrometry using cellulose-based chiral stationary phase

A sensitive, specific and rapid liquid chromatography-mass spectrometry (LC-MS/MS) method has been developed and validated for enantioselective determination of darusentan enantiomers, orally active potent endothelin-A receptor antagonist, in rat plasma. The plasma samples were pretreated by protein precipitation with methanol and baseline chromatographic separation was performed on a Chiralcel OD-RH column with a mobile phase consisting of acetonitrile/water/formic acid (50:50:0.1, v/v/v) at a flow rate of 0.5 mL/min. The detection was accomplished by multiple-reaction monitoring (MRM) scanning via electrospray ionization (ESI) source operating in the negative ionization mode. The calibration curve was linear over the investigated concentration from 0.500 to 2500 ng/mL (r≥0.995) for each enantiomer using 50 μL of rat plasma. The lower limit of quantitation (LLOQ) for each enantiomer was 0.500 ng/mL. The intra- and inter-day precisions were not more than 10.2% and the accuracy was within the range from -5.4 to 6.3% for darusentan enantiomers. No chiral inversion was observed during the plasma preparation, storage and analysis. The method proved adequate for enantioselective pharmacokinetic studies of darusentan enantiomers after oral administration of three different doses of racemic darusentan.     

Hybridation of different chiral separation techniques with ICP-MS detection for the separation and determination of selenomethionine enantiomers: chiral speciation of selenized yeast

Enantioseparation and determination of selenomethionine enantiomers in selenized yeast was investigated using chiral separation techniques based on different principles, coupled on-line to inductively coupled plasma mass spectrometry (ICP-MS) for selenium-specific detection. High performance liquid chromatography (HPLC) on a beta-cyclodestrin (beta-CD) column, cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC), gas chromatography (GC) on a Chirasil-L-Val column, and HPLC on a Chirobiotic T column have been investigated as the chiral separation techniques. For HPLC separation on the beta-CD column, and also for CD-MEKC, selenomethionine enantiomers were derivatized with NDA/CN(-). For chiral separation by GC, selenomethionine enantiomers were converted into their N-trifluoroacetyl (TFA)-O-alkyl esters. The developed hybridation methodologies are compared with respect to enantioselectivity, sensitivity and analysis time. The usefulness of the best-suited method [HPLC (Chirobiotic T)-ICP-MS] was demonstrated by its application to the successful chiral speciation of selenium and D-and L-selenomethionine content determination in selenized yeast.     

Determination of (R)- and (S)-ketoprofen in human plasma by liquid chromatography/tandem mass spectrometry following automated solid-phase extraction in the 96-well format

A sensitive and selective method was developed for the determination of (R)-ketoprofen ((R)-kt) and (S)-ketoprofen ((S)-kt) in human plasma using chiral liquid chromatography/tandem mass spectrometry (LC/MS/MS). Plasma samples spiked with stable-isotope-labeled [(13)C(1), (2)H(3)]-(R and S)-ketoprofen, for use as the internal standards, were prepared for analysis using automated solid-phase extraction (SPE) in the 96-well microtiter format. The enantiomers were separated on an (R)-1-naphthylglycine and 3,5-dinitrobenzoic acid (Chirex 3005) 250x2.0 mm i.d. analytical column, equipped with a 30x2.0 mm i.d. guard column using isocratic mobile phase conditions. The (R)- and (S)-kt levels were quantifiable from 0.05 to 2500 ng ml(-1) by constructing two separate curves from calibration standards covering the same range. The first curve ranged from 0.05 to 100 and the second from 100 to 2500 ng ml(-1). A concentration of 0.05 ng ml(-1) of either enantiomer was easily detected using a 1 ml plasma sample volume. The average method accuracy, evaluated at four levels over an extended period, was better than +/-3% over the entire range. The precision for the same set of quality control samples ranged from 4.0 to 7.0 % RSD (n = 24). The method was applied to the evaluation of pharmacokinetic parameters in human plasma obtained from volunteers who received 25 mg of kt by peroral administration of Actron caplets or by topical administration of Oruvail gel.     

Liquid chromatography-tandem mass spectrometry for the determination of a new oxazolidinone antibiotic DA-7867 in human plasma

A liquid chromatography-tandem mass spectrometric (LC/MS/MS) method for the determination of a new ox-azolidinone antibiotic DA-7867, (S)-[N-3-(4-(2-(1-methyl-5-tetrazolyl)-pyridine-5-yl)-3- fl uorophenyl)-2-oxo-5-oxazolidinyl]methyl acetamide, in human plasma was developed. DA-7867 and internal standard, linezolid, were extracted from human plasma with ethyl acetate at acidic pH. A reverse-phase LC separation was performed on Luna C(8) column with the mixture of acetonitrile-ammonium formate (10 mm, pH 4.5; 35:65, v/v) as mobile phase. The analytes were determined using an electrospray ionization tandem mass spectrometry in the multiple-reaction-monitoring mode. The lower limits of quanti fi cation for DA-7867 was 2.5 ng/mL. The single liquid-liquid extraction quantitatively recovered DA-7867 and internal standard from plasma samples at the ranges of 82.2-86.7%. DA-7867 was stable in blank human plasma at room temperature for 24 h and following three freeze-thaw cycles.     

Enantiomer separations by capillary electrochromatography using chiral stationary phases

The applicability of capillary electrochromatography (CEC) using packed capillary column to enantiomer separations was investigated. As chiral stationary phases, OD type packing materials of 5 and 3 microm particle diameters, originally designed for conventional high-performance liquid chromatography (HPLC) were employed. The chiral packing materials were packed by a pressurized method into a 100 microm I.D. fused-silica capillary. Several racemic enantiomers, such as acidic, neutral and basic drug components, were successfully resolved, typically by using acidic or basic solutions containing acetonitrile as mobile phases. The separation efficiencies for some enantiomers in the chiral CEC system using the 5 microm OD type packing were superior to those obtained in HPLC using chiral packings. The plate heights obtained for several enantiomers were 8-13 microm or the reduced plate height of 1.6-2.6, which indicates the high efficiency of this chiral CEC system.     

A new application of stopped-flow chiral HPLC: inversion of enantiomer elution order

A newly developed procedure to reverse the enantiomer elution order of compounds resolved on chiral stationary phases (CSPs) for HPLC is presented. The optimized analytical protocol is based on the effect of temperature on enantioselectivity and does not involve any changing in mobile phase composition or type of CSP. In essence, the approach entails variable temperature chromatography at two temperatures. The enantiomer separation is performed at a low column temperature, with stopping the flow prior to elution of the less retained enantiomer. Then, the column temperature is changed with the peaks trapped inside the column, followed by elution with the same mobile phase in reverse direction. Under these conditions, the more pronounced loss in free energy of binding for the more strongly bound enantiomer results in an inversion of the elution order. This procedure may be applied to each enantiomer pair that is separated by chiral HPLC under an appreciable enthalpy-control.     

Direct simultaneous analysis of plasma samples for a drug discovery compound and its hydroxyl metabolite using mixed-function column liquid chromatography-tandem mass spectrometry

A polymer-coated mixed-function (PCMF) column was evaluated for direct plasma injection for the simultaneous determination of a drug candidate and its hydroxyl metabolite by high-performance liquid chromatography (HPLC) with tandem mass spectrometry (MS-MS) in support of pharmacokinetic studies. Each diluted monkey plasma sample containing internal standard was directly injected on to the PCMF column for sample clean-up, enrichment and chromatographic separation. The proteins and macromolecules were first eluted from the column while the drug molecules were retained on the bonded hydrophobic phase. The analytes retained on the column were then eluted with a strong mobile phase using a gradient separation technique at a constant flow rate of 1.0 ml min(-1). When not diverted, the column effluent was connected either to the atmospheric pressure chemical ionization (APCI) source or the electrospray ionization (ESI) source as part of the mass spectrometer system used for quantification. The calibration curve was linear over the range 5-2500 ng ml(-1) for both analytes. The retention times for the analytes and the internal standard were both consistent and no column deterioration was observed for at least 500 injections. The recovery through the column and reproducibility of the dosed compound and its hydroxyl metabolite in monkey plasma samples were > 90% (RSD < 6%). The total analysis time was < 8 min per sample. The analytical results obtained by the proposed direct plasma injection method were in good agreement with those obtained by the conventional LC-MS-MS method.     

Development of direct stereoselective and non-stereoselective assays in biological fluids for the enantiomers of a thieno[2,3-b]thiopyran-2-sulfonamide, a topically effective carbonic anhydrase inhibitor

A stereoselective assay for the optical isomers [(S) and (R)] of 5,6-dihydro-4-[(2-methylpropyl)amino]-4H-thieno[2,3-b]thiopyran-2- sulfonamide-7,7-dioxide in human whole blood has been developed. The assay is based on direct enantiomer separation on a chiral stationary phase column of bovine serum albumin attached to silica. The effect of pH, ionic strength, column length and organic modifier on chiral separation has been studied. The assay methodology, based on high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection (252 nm), has been fully validated in the concentration range 25-250 ng/ml of each enantiomer. Since no interconversion of the isomers was observed in vivo for the clinical studies involving the single (S)-enantiomer, a more sensitive (2.5 ng/ml), non-stereoselective assay has been developed. This method, also based on HPLC with UV detection, was fully validated in whole blood, plasma and urine in the concentration range 2.5-100 ng/ml. The details of these assays, together with some representative data from a pilot human study, are also presented.     

液相色谱-大气压化学电离质谱法分析人参中的人参皂甙

研究了用反相高效液相色谱-大气压化学电离质谱(HPLC/APCI-MS)分析人参皂甙的方法。液相色谱采用乙腈-水流动相进行梯度洗脱,质谱采用正负离子同时扫描并结合二级质谱进行定性,用选择反应离子模式(SRM)测定检测限。实验发现虽然人参皂甙是热不稳定物质,但在大气压化学电离质谱的高温汽化过程中仍能检测到很强的负离子分子离子峰,而且随着汽化温度的升高,人参皂甙的负离子分子离子峰的强度增加。该方法对人参皂甙Rb1和Rg1的检测限分别为1.2×10-13 g和3.0×10-14 g,并检测出白参中包括丙二酰人参皂甙在内的29种人参皂甙。该法灵敏度高,重复性好,结果准确,能有效地对药材提取物中的多种人参皂甙进行检测和结构分析。     

Enantiomer elution order reversal of fluorenylmethoxycarbonyl-isoleucine in high-performance liquid chromatography by changing the mobile phase temperature and composition

In this paper the elution order reversal of enantiomers of fluorenylmethoxycarbonyl- or FMOC-isoleucine is described depending on the separation temperature and composition of the mobile phase when using the polysaccharide-based chiral column Lux Cellulose-1 in HPLC with normal-phase eluent. Reversal of the enantiomer elution order (EEO) in HPLC depending on the column temperature and content of the polar modifier in the mobile phase has been reported before in the literature. However, EEO reversal by changing the content of acidic modifier in the mobile phase seems to be described for the first time in the present work.     

A stereospecific high-performance liquid chromatographic assay for the determination of ketoconazole enantiomers in rat plasma

A stereospecific high-performance liquid chromatographic assay was developed for the quantitation of ketoconazole enantiomers (KTZ) in rat plasma. After protein precipitation of 100 microL plasma using acetonitrile, a wash step was performed using hexane. The supernatant was removed and KTZ enantiomers and amiodarone, the internal standard, were extracted using liquid-liquid extraction with tert-butyl methyl ether. After transfer and evaporation of the organic layer, the residue was reconstituted in mobile phase and injected into the HPLC through a chiral column. The mobile phase consisted of hexane:ethanol:2-propanol with diethyl amine, pumped at 1.5 mL/min. All components eluted within 18 min. KTZ enantiomers were baseline resolved and peaks were symmetrical in appearance with no interferences. Calibration curves were linear over the range 62.5-5000 ng/mL of enantiomer. The intraday and interday CV% assessments were 相似文献   

Stereoselective high-performance liquid chromatographic assay for pirmenol enantiomers in dog plasma.

Pirmenol enantiomers in dog plasma were quantified using a stereospecific high-performance liquid chromatographic method with ultraviolet detection at 262 nm. Racemic pirmenol and internal standard, (+)-propranolol, were isolated from dog plasma by a three-step extraction procedure using toluene, 0.1 M hydrochloric acid and hexane, respectively. A chiral analytical column (Chiralcel OJ) was used with a mobile phase consisting of hexane-isopropanol-diethylamine (98.9:1.0:0.1). Linear calibration curves were obtained in the concentration range 0.0200-5.00 micrograms/ml for each enantiomer. Precision of the method, expressed as coefficient of variation for nine quality control samples, was 7.1% for (+)-pirmenol and 6.4% for (-)-pirmenol. Bias was +/- 2.2% for (+)-pirmenol and +/- 1.5% for (-)-pirmenol in quality control samples.     

Determination of molindone enantiomers in human plasma by high-performance liquid chromatography-tandem mass spectrometry using macrocyclic antibiotic chiral stationary phases

A sensitive and selective bioanalytical assay was developed and validated for the determination of enantiomeric molindone in human plasma using high-performance liquid chromatography-tandem mass spectrometry along with supported liquid extraction procedures. The chiral separation was evaluated and optimized on macrocyclic antibiotic type chiral stationary phases (CSPs) based on teicoplanin aglycone (Chirobiotic TAG) in polar organic, polar ionic, and reversed-phase mode chromatography, respectively. Complete baseline separation was achieved on a Chirobiotic TAG column under isocratic condition in reversed-phase chromatography. The method validation was conducted using a Chirobiotic TAG column (100 mm x 2.1 mm) over the curve range 0.100-100 ng/ml for each molindone enantiomer using 0.0500 ml of plasma sample. The flow rate was 0.8 ml/min and the total run time was 9 min. Supported liquid extraction in a 96-well plate format was used for sample preparation. Parameters including recovery, matrix effect, linearity, sensitivity, specificity, carryover, precision, accuracy, dilution integrity, and stability were evaluated. The intra- and inter-day precision and accuracy of the quality control samples at low, medium, and high concentration levels were RSD 相似文献   

Comparison of SSI with APCI as an interface of HPLC-mass spectrometry for analysis of a drug and its metabolites

Sonic spray ionization (SSI) was compared with atmospheric pressure chemical ionization (APCI) as an interface of high-performance liquid chromatography (HPLC)-mass spectrometry (MS) for sensitive analyses of a neuroleptic drug, haloperidol and its two metabolites, such as reduced haloperidol and 4-(4-chlorophenyl)-4-hydroxypiperidine (CPHP), in biological samples. For both SSI and APCI interfaces, HPLC-MS-MS gave higher sensitivity than HPLC-MS. The sensitivities by HPLC-SSI-MS-MS for haloperidol and reduced haloperidol were 100 and 30 times higher, respectively, than those by HPLC-APCI-MS-MS; no spectrum with recognizable peaks was obtained for CPHP with the APCI interface. Therefore, detection limits and regression equations were examined by the HPLC-SSI-MS-MS for human plasma and urine samples spiked with the above drug and its metabolites. Haloperidol, reduced haloperidol, and CPHP showed good linearity in the ranges of 5-800, 10-800, and 100-800 ng/mL, respectively, for both human plasma and urine; their detection limits were 2.5, 5, and 75 ng/mL, respectively, using a new polymer HPLC column which enabled direct application of biological samples.     

Development and Validation of a Chiral Liquid Chromatographic Assay for Enantiomeric Separation and Quantification of Verapamil in Rat Plasma: Stereoselective Pharmacokinetic Application

A novel, fast and sensitive enantioselective HPLC assay with a new core–shell isopropyl carbamate cyclofructan 6 (superficially porous particle, SPP) chiral column (LarihcShell-P, LSP) was developed and validated for the enantiomeric separation and quantification of verapamil (VER) in rat plasma. The polar organic mobile phase composed of acetonitrile/methanol/trifluoroacetic acid/triethylamine (98:2:0.05: 0.025, v/v/v/v) and a flow rate of 0.5 mL/min was applied. Fluorescence detection set at excitation/emission wavelengths 280/313 nm was used and the whole analysis process was within 3.5 min, which is 10-fold lower than the previous reported HPLC methods in the literature. Propranolol was selected as the internal standard. The S-(−)- and R-(+)-VER enantiomers with the IS were extracted from rat plasma by utilizing Waters Oasis HLB C18 solid phase extraction cartridges without interference from endogenous compounds. The developed assay was validated following the US-FDA guidelines over the concentration range of 1–450 ng/mL (r² ≥ 0.997) for each enantiomer (plasma) and the lower limit of quantification was 1 ng/mL for both isomers. The intra- and inter-day precisions were not more than 11.6% and the recoveries of S-(−)- and R-(+)-VER at all quality control levels ranged from 92.3% to 98.2%. The developed approach was successfully applied to the stereoselective pharmacokinetic study of VER enantiomers after oral administration of 10 mg/kg racemic VER to Wistar rats. It was found that S-(−)-VER established higher C_max and area under the concentration-time curve (AUC) values than the R-(+)-enantiomer. The newly developed approach is the first chiral HPLC for the enantiomeric separation and quantification of verapamil utilizing a core–shell isopropyl carbamate cyclofructan 6 chiral column in rat plasma within 3.5 min after solid phase extraction (SPE).     

A novel chiral column for the HPLC separation of a series of dansyl amino and arylalkanoic acids

In a previous paper [C. Andre, M. Thomassin, A. Umrayami, L. Ismaili, B. Refouvelet, Y.C. Guillaume, Talanta 71 (2007) 1817] a novel cyclic hexapeptide molecule dissolved in the mobile phase was evaluated as a chiral selector (CS) for the enantiomer separation of a series of dansyl amino and arylalkanoic acids using high performance liquid chromatography (HPLC). In this paper, this CS was immobilized to the surface of a monolithic support and the enantioselectivity and the performance of this novel column are discussed.     

Development and validation of a liquid chromatographic/tandem mass spectrometric method for the determination of sertraline in human plasma

A sensitive and rapid liquid chromatographic/tandem mass spectrometric method was developed and validated for the determination of sertraline in human plasma. The analyte and internal standard (IS, diphenhydramine) were extracted with 3 mL of diethyl ether/dichloromethane (2:1, v/v) from 0.25 mL plasma, then separated on a Zorbax Eclipse XDB C18 column using methanol/water/formic acid (75:25:0.1, v/v/v) as the mobile phase. The triple quadrupole mass spectrometry was applied via an atmospheric pressure chemical ionization (APCI) source for detection. The fragmentation pattern of the protonated sertraline was elucidated with the aid of product mass spectra of isotopologous peaks. Quantification was performed using selected reaction monitoring of the transitions of m/z 306 --> 159 for sertraline and m/z 256 --> 167 for the IS. The method was linear over the concentration range of 0.10-100 ng/mL. The intra-day and inter-day precisions, expressed by relative standard deviation, were both less than 6.7%. Assay accuracies were within +/-6.9% as terms of relative error. The lower limit of quantification (LLOQ) was identifiable and reproducible at 0.10 ng/mL with a precision of 8.3% and an accuracy of 9.6%. The validated method has been successfully applied for the pharmacokinetic study and bioequivalence evaluation of sertraline in 18 healthy volunteers after a single oral administration of 50 mg sertraline hydrochloride tablets.     

The chiral bioconversion and preclinical pharmacokinetic analysis of (R)‐(+)‐rabeprazole in beagle dogs by HPLC and HPLC‐MS/MS

In order to accurately investigate the preclinical pharmacokinetics of (R)‐(+)‐rabeprazole sodium injection, a reliable high‐performance liquid chromatography (HPLC) method was developed using a Chiral‐AGP column to prove that there is no chiral bioconversion of (R)‐(+)‐rabeprazole to (S)‐(?)‐rabeprazole in beagle dogs after single intravenous administration of (R)‐(+)‐rabeprazole sodium injection. An HPLC–tandem mass spectrometry (HPLC‐MS/MS) method for analysis of (R)‐(+)‐rabeprazole was developed and validated, and used to acquire the pharmacokinetic parameters in beagle dogs. (R)‐(+)‐Rabeprazole and internal standard omeprazole were extracted from plasma samples by protein precipitation and separated on a C₁₈ column using methanol–5 mm ammonium acetate as mobile phase. Detection was performed using a turbo‐spray ionization source and mass spectrometric positive multi‐reaction monitoring mode. The linear relationship was achieved in the range from 2.5 to 5000 ng/mL. The method also afforded satisfactory results in terms of sensitivity, specificity, precision, accuracy and recovery as well as the stability of the analyte under various conditions, and was successfully applied to a preclinical pharmacokinetic study in beagle dogs after single intravenous administrations of (R)‐(+)‐rabeprazole sodium injection at 0.33, 2 and 6 mg/kg. Copyright © 2013 John Wiley & Sons, Ltd.