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A sensitive method was developed for the simultaneous determination of midazolam and propofol in human plasma samples via modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction for their analysis by gas chromatography–tandem mass spectrometry (GC–MS/MS). Detailed optimization and validation experiments were conducted; plasma quality control samples spiked with two drugs and two internal standards (ISs) were extracted using the QuEChERS technique and determined by GC–MS/MS. The present method was applied to the measurements in an actual clinical case. The regression equations for midazolam and propofol in plasma displayed good linearity (r > 0.9978) from 10 to 1000 ng/mL with a limit of quantification of 10 ng/mL. The intra- and interday precisions for both drugs were not greater than 8.6%. The accuracies of quantitation ranged from 98 to 110%. The extraction efficiencies of midazolam and propofol for plasma were 93 to 117%. The method was successfully applied to the analyses of plasma midazolam and propofol concentrations in a brain-injured patient subjected to hypothermia, which validated the present methodology. In this study, the authors have successfully established the detailed procedure for GC–MS/MS analysis of midazolam and propofol in human plasma. The sensitivity and specificity of the present method for the drugs were almost comparable to those by the standard liquid chromatography–tandem mass spectrometry. To their knowledge, this is the first report for analysis of midazolam/propofol by GC–MS/MS.

Forensic toxicological analyses of drugs and their metabolites in human specimens usually require extractive pretreatment for successful analysis of substances from the matrix. In the present study, a high-throughput method was developed to analyze flunitrazepam, 7-aminoflunitrazepam, 7-acetamidoflunitrazepam, 7-acetamido-3-hydroxyflunitrazepam, and 3-hydroxyflunitrazepam in human plasma and urine samples using a new Monolithic C18 gel-packed SpinTip and ultra-performance liquid chromatography (UPLC)–quadrupole time-of-flight (Q-ToF) mass spectrometry (MS). Plasma (20 µL) or urine (100 µL) samples spiked with each component were extracted using a Monolithic C18 SPE SpinTip and quantified by UPLC–Q-Tof–MS with positive-ion electrospray ionization (ESI). Good separation, with clear peak shapes of flunitrazepam and its metabolites, was achieved within an analysis time of 6 min, including the extraction time. Recoveries of flunitrazepam and 7-aminoflunitrazepam for plasma and urine samples were 93.5–118% and 97.7–109%, respectively. The regression equations for flunitrazepam and 7-aminoflunitrazepam showed excellent linearity in the range of 0.5–250 ng/mL for plasma and 0.4–500 ng/mL for urine, with detection limits of 0.2–0.5 ng/mL. Intra- and inter-day coefficients of variations for two drugs are smaller than 13.5%. The accuracy of quantitation was 89–110%. The method was successfully applied to determine the level of flunitrazepam and its metabolites in human plasma and urine, respectively, after oral administration to a volunteer.

Aminoglycosides are a class of broad-spectrum antibiotics with several clinical uses. Owing to the ototoxicity and nephrotoxicity of aminoglycosides, therapeutic drug monitoring is required. This study aimed to devise a high-throughput method for identification and quantitative determination of aminoglycoside antibiotics in human plasma samples using ultra-performance liquid chromatography–quadrupole time-of-flight-mass spectrometry (UPLC–Q-ToF-MS). Plasma samples (100 µL) spiked with five aminoglycosides (streptomycin, spectinomycin, amikacin, kanamycin, and gentamycin) and an internal standard (ribostamycin) were diluted and centrifuged in aqueous formic acid and acetonitrile. The clear supernatant extract was evaporated and reconstituted in the mobile phase, of which 4 µL was subjected to UPLC–Q-ToF-MS. Prominent peaks were observed for the drugs within 3 min. The recoveries of five aminoglycosides from plasma samples were 92.6–120%. The regression equations showed excellent linearity (0.9999 ≥ r2 ≥ 0.9987) within the range of 1.0–100 µg/mL, and detection limits of 0.5–2.0 µg/mL. The coefficients of the intra- and inter-day variations for five drugs were less than 11.8%, while the accuracy of quantitation was in the range of 89–111%. In this study, a novel method was presented for identification and determination of aminoglycosides in human plasma samples using UPLC–Q-ToF-MS analysis. This method can be applied to high-throughput analysis used for clinical and environmental purposes.

A simple and sensitive method was developed and validated here for the analysis of thirteen nonsteroidal anti-inflammatory drugs (NSAIDs) in human plasma samples by hydrophilic interaction liquid chromatography (HILIC)-tandem mass spectrometry (MS/MS). A small volume of plasma (20μL) spiked with compounds was diluted with 80μL of 10-mM ammonium acetate followed by a simple protein precipitation with 400μL of acetonitrile. After centrifugation, the clear supernatant extract was directly injected into the HILIC-MS/MS, without any solvent evaporation and reconstitution steps. The chromatographic separation of the NSAIDs was achieved on a Unison UK-Amino HILIC column (50mm×3mm i.d., particle size 3μm) with a linear gradient elution system composed of 10mM ammonium acetate (pH 6.8) and acetonitrile at a flow rate of 0.4mL/min. The mass spectra obtained by HILIC-MS showed base peak ions due to [M+H](+) for indomethacin, oxaprozin, ketoprofen, alminoprofen, zaltoprofen, tiaprofenic acid, pranoprofen, and ketoprofen-d3 and due to [M-H](-) for etodolac, ibuprofen, diclofenac, fenoprofen, loxoprofen, naproxen, and ibuprofen-d3. Recoveries of these thirteen NSAIDs in plasma were 34.8-113% and the lower limits of quantitation were 0.125-1.25μg/mL. The intra- and interday coefficient of variations for all drugs in plasma were less than 14.6%. The data obtained from actual plasma determinations of zaltoprofen, ibuprofen, and diclofenac are also presented.

A high-throughput method was developed for determinations of eight barbiturates (barbital, allobarbital, phenobarbital, cyclobarbital, amobarbital, secobarbital, thiopental, and thiamylal) in human plasma by on-line column-switching ultra-fast liquid chromatography–tandem mass spectrometry (MS–MS). Plasma samples (100 μl) spiked with the eight barbiturates and 5-(4-methylphenyl)-5-phenylhydantoin (internal standard) were diluted with 300 μl of 13.3 mM ammonium acetate/acetonitrile (33:67, v/v). After centrifugation and filtration, the clear supernatant was injected directly onto the extraction column (Oasis HLB cartridge column). The following procedure was fully automated. The analytes retained on the extraction column were eluted by backflushing of the extraction column and introduced onto the analytical column (Phenomenex Onyx monolithic C18 column, 100 mm × 4.6 mm i.d.) by column switching. Quantification was performed by multiple reaction monitoring with negative-ion atmospheric pressure chemical ionization. Good peak separation and peak shapes of the eight drugs were achieved within an analysis time of 3 min, including the extraction time. All drugs spiked into plasma showed recoveries of 80–93 %. The regression equations for the eight drugs showed excellent linearities in the range of 10–5000 ng/ml of plasma, and the limits of detection ranged from 1.0 to 10 ng/ml. The lower and upper limits of quantitation were 10–50 ng/ml and 5000 ng/ml, respectively. Intraday and interday coefficients of variation for all the drugs were not >9.1 %. The accuracies of quantitation were 92.0–108 %. The method was successfully applied to determination of the level of amobarbital in human plasma after its oral administration to a volunteer.

Three tetracyclic antidepressants, mianserin, mirtazapine, and setiptiline, were extracted from human plasma samples using a new micropipette solid-phase extraction tip containing a monolithic silica gel packing material, the MonoTip C18. The plasma samples (0.1 ml), which contained mianserin, mirtazapine, and setiptiline, were mixed with 330 μl of distilled water and 50 μl of 0.5 M glycine–sodium hydroxide buffer solution (pH 8). After centrifugation, the supernatant was extracted onto the C18 phase of the tip (pipette tip volume, 200 μl) by 25 sequential aspirating/dispensing cycles. The three analytes retained in the C18 phase were eluted with methanol by 5 aspirating/dispensing cycles. The eluate was subjected to measurements by gas chromatography (GC) with nitrogen–phosphorus detection (NPD). The recoveries of the three antidepressants were 84.6–99.6% and the limits of detection for each drug were between 2.4 and 15 ng/ml of plasma. The maximum intraday and interday coefficients of variation for the drugs was below 10.6%. Regression equations for the three drugs showed excellent linearity in the range of 50–5000 ng/ml for mianserin and mirtazapine and 50–10 000 ng/ml for setiptiline. The antidepressants were stable for at least 12 h at 4°C, 4 weeks at −80°C, and through three freeze–thaw cycles in plasma. The validated method was successfully used to quantify the plasma concentrations of mirtazapine in a human subject after oral administration of the drug. Although we achieved analyte detection with GC-NPD, the present monolithic micropipette extraction method for tetracyclic antidepressants seems to be very useful for combining it with GC–mass spectrometry (MS) and/or liquid chromatography–tandem MS to secure high simplicity, purification, reproducibility, and sensitivity.

Six nonsteroidal anti-inflammatory drugs (NSAIDs) in human plasma samples were analyzed by liquid chromatography (LC)-electrospray ionizationtandem mass spectrometry (MS-MS) using a hydrophilic polymer column (MSpak GF-310 4B), which enabled direct injection of crude biological samples. Separation of the six NSAIDs, alminoprofen, flurbiprofen, ibuprofen, pranoprofen, tiaprofenic acid, and zaltoprofen, was carried out using gradient elution with 10 mM ammonium acetate/acetonitrile. The mass spectra obtained by LC-single stage MS showed base peak ions due to [M+H]+ for alminoprofen, zaltoprofen, tiaprofenic acid, and pranoprofen, and [M-H]- for ibuprofen and flurbiprofen. Product ions were produced from each [M+H]+ or [M-H]- ion in the tandem mode. Quantitation was performed by multiple reaction monitoring with switching from positive to negative ion mode and vice versa. All drugs spiked into plasma showed recoveries of 77.0%–88.2%. The regression equations for the six drugs showed excellent linearity in the range of 0.01–25 μg/ml of plasma, and limits of detection were in the range of 0.002–0.005 μg/ml. Limits of quantitation were 0.01–0.02 μg/ml. Intraday and interday coeffi cients of variation for all drugs in plasma were not greater than 8.1%. The accuracy of quantitating the six drugs was in the range of 94.5%–110%. Data obtained from actual determinations of the levels of alminoprofen, pranoprofen, and ibuprofen in human plasma after oral administration are also presented.

A method for the simultaneous extraction of four tricyclic antidepressants from human plasma samples using pipette tip SPE with MonoTip C(18) tips is presented. Human plasma (0.1 mL) containing four tricyclic antidepressants (amitriptyline, amoxapine, imipramine, and trimipramine) and an internal standard (IS), protriptyline, was mixed with 0.4 mL of distilled water and 100 microL 1 M NaOH solution. After centrifugation of the mixture, the supernatant was extracted to the C(18) phase of the tip by 20 repeated aspirating/dispensing cycles using a manual micropipettor. The analytes retained in the tip were eluted with methanol by five repeated aspirating/dispensing cycles. Without evaporation and reconstitution, the eluate was directly injected into a gas chromatograph injector and detected by a mass spectrometer with SIM in the positive-ion electron impact mode. Recovery of the four antidepressants and IS spiked into human plasma was 80.2-92.1%. The regression equations for the four antidepressants showed excellent linearity in the range of 0.2-40 ng/0.1 mL. LODs and LOQs for the four drugs were 0.05-0.2 ng/0.1 mL and 0.2-0.5 ng/0.1 mL, respectively. Intra- and interday CVs for the four drugs in plasma were no greater than 9.5%.

Methamphetamine and amphetamine were extracted from human whole blood samples using pipette tip solid-phase extraction (SPE) with MonoTip C(18) tips, on which C(18)-bonded monolithic silica gel was fixed. Human whole blood (0.1 mL) containing methamphetamine and amphetamine, with N-methylbenzylamine as an internal standard, was mixed with 0.4 mL of distilled water and 50 microL of 5 M sodium hydroxide solution. After centrifugation, the supernatant was extracted to the C(18) phase of the tip (pipette tip volume, 200 microL) by 25 repeated aspirating/dispensing cycles using a manual micropipettor. Analytes retained in the C(18) phase were eluted with methanol by five repeated aspirating/dispensing cycles. After derivatization with trifluoroacetic anhydride, analytes were measured by gas chromatography - mass spectrometry with selected ion monitoring in the positive-ion electron impact mode. Recoveries of methamphetamine and amphetamine spiked into whole blood were more than 87.6 and 81.7%, respectively. Regression equations for methamphetamine and amphetamine showed excellent linearity in the range of 0.5-100 ng/0.1 mL. The limits of detection for methamphetamine and amphetamine were 0.15 and 0.11 ng/0.1 mL, respectively. Intra- and interday coefficients of variation for both stimulants were not greater than 9.6 and 13.8%, respectively. The determination of methamphetamine and amphetamine in autopsy whole blood samples is presented, and was shown to validate the present methodology.

A method for the simultaneous determination of selegiline and its metabolite, desmethylselegiline, in human whole blood and urine is presented. The method, which combines a fiber-based headspace solid-phase microextraction (SPME) technique with gas chromatography-mass spectrometry (GC-MS), required optimization of various parameters (e.g., salt additives, extraction temperatures, extraction times and the extraction properties of the SPME fiber coatings). Pargyline was used as the internal standard. Extraction efficiencies for both selegiline and desmethylselegiline were 2.0-3.4% for whole blood, and 8.0-13.2% for urine. The regression equations for selegiline and desmethylselegiline extracted from whole blood were linear (r(2)=0.996 and 0.995) within the concentration ranges 0.1-10 and 0.2-20 ng/ml, respectively. For urine, the regression equations for selegiline and desmethylselegiline were linear (r(2)=0.999 and 0.998) within the concentration ranges 0.05-5.0 and 0.1-10 ng/ml, respectively. The limit of detection for selegiline and desmethylselegiline was 0.01-0.05 ng/ml for both samples. The lower and upper limits of quantification for each compound were 0.05-0.2 and 5-20 ng/ml, respectively. Intra- and inter-day coefficients of variation for selegiline and desmethylselegiline in both samples were not greater than 8.7 and 11.7%, respectively. The determination of selegiline and desmethylselegiline concentrations in Parkinson's disease patients undergoing continuous selegiline treatment is presented and is shown to validate the present methodology.

Mequitazine has been found to be extractable from human plasma samples using MonoTip C 18 tips, inside which C 18 -bonded monolithic silica gel was fixed. Human plasma (0.1 mL) containing mequitazine and cyproheptadine as an internal standard (IS) was mixed with 0.4 mL of distilled water and 25 μL of 1 M potassium phosphate buffer (pH 8.0). After centrifugation of the mixture, the supernatant fraction was extracted to the C 18 phase of the tip by 25 repeated aspirating/dispensing cycles using a manual micropipettor. The analytes retained on the C 18 phase were then eluted with methanol by five repeated aspirating/dispensing cycles. Without evaporation and reconstitution, the eluate was injected into a gas chromatograph injector and detected by a mass spectrometer with selected ion monitoring in the positive-ion electron impact mode. The separation of mequitazine and the IS from each other and from impurities was generally satisfactory using a DB-1MS capillary column (30 m × 0.32 mm i.d., film thickness 0.25 μm). The recoveries of mequitazine and the IS spiked into plasma were more than 90.0%. The regression equation for mequitazine showed excellent linearity in the range of 0.2–200 ng 0.1 mL −1 , and the detection limit was 0.05 ng 0.1 mL −1 of plasma. The intra-day and inter-day coefficients of variation for mequitazine in human plasma were not greater than 8.16 and 9.24%, respectively. Accuracy for the drug was in the range of 90.0–97.4%. The data obtained from determination of mequitazine in human plasma after oral administration of the drug are also presented.

Ten antihistamine drugs, diphenhydramine, orphenadrine, chlorpheniramine, diphenylpyraline, triprolidine, promethazine, homochlorcyclizine, cyproheptadine, cloperastine and clemastine, have been found to be extractable from human plasma samples using MonoTip C18 tips, inside which C18-bonded monolithic silica gel was fixed. Human plasma (0.1 mL) containing the ten antihistamines was mixed with 0.4 mL of distilled water and 25 µL of a 1 M potassium phosphate buffer (pH 8.0). After centrifugation of the mixture, the supernatant fraction was extracted to the C18 phase of the tip by 25 repeated aspirating/dispensing cycles using a manual micropipettor. The analytes retained on the C18 phase were then eluted with methanol by five repeated aspirating/dispensing cycles. The eluate was injected into a gas chromatography (GC) injector without evaporation and reconstitution steps, and was detected by a mass spectrometer with selected ion monitoring in the positive-ion electron impact mode. The separation of the ten drugs from each other and from impurities was generally satisfactory using a DB-1MS column (30 m × 0.32 mm i.d., film thickness 0.25 µm). The recoveries of the ten antihistamines spiked into plasma were 73.8–105%. The regression equations for the ten antihistamines showed excellent linearity with detection limits of 0.02–5.0 ng/0.1 mL. The within-day and day-to-day coefficients of variation for plasma were not greater than 9.9%. The data obtained from determination of diphenhydramine and chlorpheniramine in human plasma after oral administration of the drugs are also presented. Copyright © 2006 John Wiley & Sons, Ltd.

Three muscle relaxants, tolperisone, eperisone, and tizanidine, were found to be extractable from human whole blood and urine samples by solid‐phase extraction (SPE) with a Sep‐Pak C18 cartridge. Their determination was made using capillary gas chromatography with nitrogen phosphorus detection. Recoveries of the three drugs were 80.0%–97.2% for whole blood and 82.0%–94.5% for urine. The coefficients of within‐day variation in terms of recovery for all compounds in whole blood and urine samples were 2.2%–9.1% and 6.9%–9.6%, respectively; those of day‐to‐day variation for the compounds in both samples were not greater than 18.1%. The regression equations for the compounds showed excellent linearity with detection limits of 1.6–7.7 ng mL−1 for whole blood and 6.0–8.0 ng mL−1 for urine. The data obtained for actual determination of tolperisone in a subject after ingestion of the drugs are also presented.

Three benzodiazepines, etizolam, brotizolam and lorazepam, have been analyzed from human plasma and urine samples by high-performance liquid chromatography–mass spectrometry (HPLC–MS) with a new polymer column (MSpak GF), which enabled direct injection of crude biological samples. The recoveries of the three benzodiazepines spiked into plasma and urine were 81.7–90.7 and 78.7–91.5%, respectively. The regression equations for the three benzodiazepines showed excellent linearity in the range 10–500 ng ml−1 of plasma or urine. The detection limits were 2 ng ml−1 for etizolam and brotizolam, 5 ng ml−1 for lorazepam in both samples. The intra- and inter-day precisions for plasma and urine were not greater than 12.7%. The data obtained from determination of the benzodiazepines in rat plasma after oral administration of the drugs are also presented.

Several extracts from marine brown alga Sargassum micracanthum (Kuetzing) Endlicher were screened for their inhibitory activity on lipid peroxidation. In an in vitro study, methanol extract (Sm-M), chloroform/ methanol (3:1) extract and ethyl acetate fraction of Sm-M inhibited lipid peroxidation in rat liver homogenates. The IC(50) values were 0.70, 0.70 and 0.37 micro g/mL, respectively. These inhibitions were stronger than vitamin C and E. These extracts showed reductive activity on DPPH, the IC(50) values were 34, 37 and 11 micro g/mL, respectively. In an in vivo study, Sm-M had the effect on CCl4 induced liver injury in rats and Sm-M (120-1200 mg/kg, p.o.) lowered dose-dependently the level of lipid peroxidation in liver.

A sensitive method for the simultaneous determination of quazepam and two of its metabolites, 2-oxoquazepam and 3-hydroxy-2-oxoquazepam, in human urine was developed using gas chromatography–mass spectrometry (GC/MS) with an Rtx-5MS capillary column. The quazepam and its metabolites were extracted from human urine using a simple solid-phase extraction Oasis ® HLB cartridge column, and the 3-hydroxy-2-oxoquazepam was derivatised using BSTFA/1%TMCS and pyridine at 60°C for 30min. The mass spectrometric detection of the analytes was performed in the full scan mode, m / z 60–480, and selected ion monitoring (SIM) mode, m / z 386, for quazepam; m / z 342, for 2-oxoquazepam; m / z 429, for 3-hydroxy-2-oxoquazepam-TMS; and m / z 284, for alprazolam-d5 (internal standard), by electron ionization. The calibration curves of quazepam and its metabolites in urine showed good linearity in the concentration range of 2.5–500ng/0.2ml of urine. The average recoveries of quazepam and its metabolites from 0.2ml of urine containing 500ng and 50ng of each drug were 71–83% and 88–90%, respectively. The limits of detection of quazepam, 2-oxoquazepam and 3-hydroxy-2-quazepam in urine by the selected ion monitoring mode were 0.096–0.37ng/ml. This method would be applicable to other forensic biological materials containing low concentrations of quazepam and its metabolites.

The evidence that some older patients with essential hypertension have low urinary dopamine excretion has brought into question the levels of urinary dopamine and plasma dopa, the major source of urinary dopamine, in young patients with essential hypertension. Twenty-four-hour urine sodium, creatinine, dopamine and noradrenaline and plasma dopa were evaluated in 48 patients with essential hypertension aged 18 to 27 years and 25 normotensive subjects. In comparison with age-matched normotensive subjects, the hypertensive patients had higher urinary dopamine (1920 +/- 80 vs 1520 +/- 130 nmol/day, p < 0.01) and noradrenaline (216 +/- 11 vs 179 +/- 12 nmol/day, p < 0.05) excretion. There was a significant correlation between urinary dopamine and noradrenaline excretion. There was no difference in plasma dopa levels between normotensive and hypertensive subjects. These results suggest that the elevated conversion of dopa to dopamine in the kidney is leading to increased urinary dopamine excretion in young patients with essential hypertension.

A novel method is described for the extraction of methamphetamine, amphetamine, and methylenedioxyphenylalkylamine designer drugs, such as 3,4-methylenedioxy-methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxyethylamphetamine, N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine, and 3,4-(methylenedioxyphenyl)-2-butanamine, from human whole blood using molecularly imprinted solid-phase extraction as highly selective sample clean-up technique. Whole blood samples were diluted with 10 mmol/L ammonium acetate (pH 8.6) and applied to a SupelMIP-Amphetamine molecularly imprinted solid-phase extraction cartridge. The cartridge was then washed to eliminate interferences, and the amphetamines of interest were eluted with formic acid/methanol (1:100, v/v). After derivatization with trifluoroacetic anhydride, the analytes were quantified using gas chromatography-mass spectrometry. Recoveries of the seven amphetamines spiked into whole blood were 89.1-102%. The limits of quantification for each compound in 200 μL of whole blood were between 0.25 and 1.0 ng. The maximum intra- and inter-day coefficients of variation were 9.96 and 13.8%, respectively. The results show that methamphetamine, amphetamine, and methylenedioxyphenylalkyl-amine designer drugs can be efficiently extracted from crude biological samples such as whole blood by molecularly imprinted solid-phase extraction with good reproducibility. This extraction method will be useful for the pretreatment of human samples before gas chromatography-mass spectrometry.

Dimemorfan was extracted from human plasma samples (100 μL) using MonoTip C(18) tips, which were packed with a C(18)-bonded monolithic silica gel attached to the inside of the tip. The samples, which contained dimemorfan and trimeprazine as an internal standard (IS), were mixed with 300 μL of distilled water and 50 μL of 1M glycine-sodium hydroxide buffer (pH 10). The mixture was extracted onto the C(18) phase of the tip by 20 sequential aspirating/dispensing cycles using a manual micropipettor. The analytes retained on the C(18) phase were then eluted with methanol by five sequential aspirating/dispensing cycles. The eluate was injected directly into a gas chromatograph and detected by a mass spectrometer with selected ion monitoring in positive electron ionization mode. An Equity-5 fused silica capillary column (30 m × 0.32 mm i.d., film thickness 0.25 μm) gave adequate separation of the dimemorfan, IS, and impurities. The recoveries of dimemorfan and the IS spiked into plasma were ≥83%. The regression equation for dimemorfan showed excellent linearity from 0.25 to 32.0 ng/100 μL of plasma, and the limit of detection was 0.125 ng/100 μL of plasma. The maximum intra-day and inter-day relative standard deviations were 13%, while accuracy ranged from 88% to 105%. Dimemorfan was stable for at least 12 h at 4°C, 4 weeks at -80°C, and three freeze-thaw cycles in plasma. This new method is expected to have application as a pretreatment for the rapid, simple, and quantitative determination of dimemorfan in plasma samples.

Methamphetamine (MA), amphetamine (AM), and the methylenedioxyphenylalkylamine designer drugs, such as 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA), N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB), 3,4-methylenedioxyamphetamine (MDA), and 3,4-(methylenedioxyphenyl)-2-butanamine (BDB), are widely abused as psychedelics. In this paper, these compounds were derivatized with trifluoroacetic (TFA) anhydride and analyzed by gas chromatography/mass spectrometry using electron ionization in positive mode. Gas chromatographic separation for TFA derivatives of all compounds was successfully resolved using an Equity-5 fused silica capillary column with a poly (5% diphenyl-95% dimethylsiloxane) stationary phase. Base peaks or prominent peaks of MA, AM, MDMA, MDEA, MBDB, MDA, and BDB appeared at m/z 154, 140, 154, 168, 168, 135, and 135, respectively. These occurred due to α-cleavage from the amide nitrogen, splitting into the TFA imine species and benzyl or methylenedioxybenzyl cations. Further prominent fragment ions at m/z 118 for MA and AM, m/z 162 for MDMA, MDEA, and MDA, and m/z 176 for MBDB and BDB were produced by cleavage of the phenylpropane or methylenedioxypropane hydrocarbon radical cation via a hydrogen rearrangement. These fragmentation pathways for the TFA derivatives of all the compounds are summarized and illustrated in this paper.

Chlorpromazine, levomepromazine, promazine, triflupromazine, and trimeprazine were simultaneously determined in human whole blood and plasma by combining headspace solid-phase microextraction and gas chromatography with nitrogenphosphorus detection. Extraction efficiency for the phenothiazine derivatives was 0.0130.117 for both sample types. Regression equations were linear [correlation coefficient (r) 0.99510.9999] within the range 2.5200 ng/0.5 mL for triflupromazine and trimeprazine, and 6.3200 ng/0.5 mL for chlorpromazine, levomepromazine, and promazine. The limit of detection for each compound was 0.23.9 ng/0.5 mL whole blood and plasma. Intraday and interday coefficients of variation for all phenothiazines in both human samples were commonly

This paper describes a fully automated on-line method combining in-tube solid-phase microextraction (SPME) in which sample clean-up and enrichment are conducted through an open tubular fused-silica capillary column and high-performance liquid chromatography (HPLC)/tandem mass spectrometry (MS/MS) detection for the determination of six butyrophenone derivatives (moperone, floropipamide, haloperidol, spiroperidol, bromperidol, and pimozide) in human plasma samples. The six butyrophenones were extracted by repeatedly aspirating and dispensing plasma sample solutions on a DB-17 capillary column (60 cm x 0.32 mm i.d., film thickness 0.25 microm). The analytes retained on the inner surface of the capillary column were then eluted into an acetonitrile-rich mobile phase using a gradient separation technique. Extraction efficiencies ranged from 12.7% to 31.8% for moperone, spiroperidol, and pimozide, and from 1.08% to 4.86% for floropipamide, haloperidol, and bromperidol. The regression equations for all compounds showed excellent linearity, ranging from 0.05 to 50 ng/0.1 mL of plasma, except for moperone and spiroperidol (0.01 to 50 ng/0.1 mL). The limits of detection and quantification in plasma for each drug were 0.03-0.2 and 0.1-0.5 ng/mL, respectively. The intra- and inter-day coefficients of variation for all compounds in plasma were not greater than 13.7%.

Diazepam and its major metabolites, nordazepam, temazepam and oxazepam, in human urine samples, were analyzed by liquid chromatography (LC)/tandem mass spectrometry (MS/MS) using a hydrophilic polymer column (MSpak GF-310 4B), which enables direct injection of crude biological samples. Matrix compounds in urine were eluted first from the column, while the target compounds were retained on the polymer stationary phase. The analytes retained on the column were then eluted into an acetonitrile-rich mobile phase using a gradient separation technique. All compounds showed base-peak ions due to [M+H]+ ions on LC/MS with positive ion electrospray ionization, and product ions were produced from each [M+H]+ ion by LC/MS/MS. Quantification was performed by selected reaction monitoring. All compounds spiked into urine showed method recoveries of 50.1-82.0%. The regression equations for all compounds showed excellent linearity in the range of 0.5-500 ng/mL of urine. The limits of detection and quantification for each compound were 0.1 and 0.5 ng/mL of urine, respectively. The intra- and inter-day coefficients of variation for all compounds in urine were not greater than 9.6%. The data obtained from actual determination of diazepam and its three metabolites, oxazepam, nordazepam and temazepam, in human urine after oral administration of diazepam, are also presented.

Seven phenothiazine derivatives, perazine, perphenazine, prochlorperazine, propericiazine, thioproperazine, trifluoperazine, and flupentixol, have been found to be extractable from human plasma and urine samples using disk solid-phase extraction (SPE) with an Empore C18 cartridge. Human plasma and urine (1 mL each) containing the 7 phenothiazine derivatives were mixed with 2 mL of 0.1M NaOH and 7 mL distilled water and then poured into the disk SPE cartridges. The drugs were eluted with 1 mL chloroform– acetonitrile (8 + 2) and determined by liquid chromatography with ammonium formate/formic acid–acetonitrile gradient elution. The detection was performed by ultraviolet absorption at 250 nm. The separation of the 7 phenothiazine derivatives from each other and from impurities was generally satisfactory using a SymmetryShield RP8 column (150 × 2.1 mm id, 3.5 μm particle size). The recoveries of the 7 phenothiazine derivatives spiked into plasma and urine samples were 64.0–89.9% and 65.1–92.1%, respectively. Regression equations for the 7 phenothiazine derivatives showed excellent linearity, with detection limits of 0.021–0.30 mg/mL for plasma and 0.017–0.30 μg/mL for urine. The within-day and day-to-day coefficients of variation for both samples were commonly below 9.0 and 14.9%, respectively.

Martefragin A (1), a novel indole alkaloid, was isolated from a red alga, Martensia fragilis, by repeated column chromatography. The structure of 1 was elucidated on the basis of spectral analysis of its methyl ester (2), including 1H- and 13C-NMR, 1H-1H correlation spectroscopy (COSY), and 13C-1H COSY. A single crystal X-ray analysis of the hydrochloride of 1 confirmed the assignment. Martefragin A (1) showed inhibitory activity on NADPH-dependent lipid peroxidation in rat liver microsomes. The IC50 values of 1, alpha-tocopherol and ascorbic acid were 2.8, 87 and 200 microM, respectively.

To investigate the hypothesis that insulin resistance plays a role in the etiology of hypertension and hyperlipidemia, we measured serum lipid levels, the fasting glucose/insulin ratio, and the insulin response to oral glucose (GTT) in a group of young obese subjects (n = 21) with hypertension and normal glucose tolerance and in normotensive subjects (n = 36) with normal glucose tolerance, matched for age and body mass index. Leisure time physical activity was evaluated by a questionnaire outlining three levels of physical activities during leisure time. Subjects with hypertension had higher fasting serum insulin (19 +/- 2 v 13 +/- 1 microU/mL, P < .01) and lower fasting glucose/insulin ratio (5.3 +/- 0.2 v 7.1 +/- 0.5 mg/dL/microU/mL, P < .01) than normotensive subjects. Subjects with hypertension had higher peak serum insulin and lower plasma glucose area/insulin area ratio in response to glucose (1.8 +/- 0.2 v 2.4 +/- 0.2 mg/dL/microU/mL, P < .05) than normotensive subjects. Serum total cholesterol, low-density cholesterol, and triglycerides were higher in the obese hypertensive subjects than in obese normotensive ones. Blood pressure correlated with either fasting serum insulin, fasting glucose/insulin ratio, or glucose area/insulin area ratio during GTT. The level of leisure time physical activities was lower in obese hypertensive subjects than in obese normotensive ones. There were significant correlations between the levels of physical activity and the fasting plasma glucose/insulin ratio (r = 0.371, P < .01) or the fasting serum insulin concentration (r = -0.282, P < .05). The study provided evidence that a low level of leisure time physical activity is associated with insulin resistance and resultant hyperinsulinemia, which are the key metabolic abnormalities that link hypertension, obesity, and hyperlipidemia in young subjects.

The effects of L-dopa on blood pressure, heart rate, plasma renin activity, norepinephrine, epinephrine and prolactin were studied in a randomized single-blind trial in 36 patients with essential hypertension. In response to L-dopa, 250 mg administered orally, the blood pressure decreased significantly as compared with the results of placebo treatment. The heart rate and plasma norepinephrine and epinephrine were unchanged. The plasma renin activity and prolactin decreased as a result of L-dopa administration. The administration of a peripheral DA2 dopamine receptor blocker, domperidone (20 mg, orally) prevented the L-dopa-induced reduction in plasma prolactin but failed to block the fall in blood pressure and plasma renin activity. These results suggest that the blood pressure-lowering effect of L-dopa may be mediated through multiple sites involving D1 dopamine receptors, the central nervous system, and the renin-angiotensin system.