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Cytisine N-methylene-(5,7-dihydroxy-4'-methoxy)-isoflavone (CNF2) is a new compound isolated from the Chinese herbal medicine Sophora alopecuroides. Preliminary pharmacodynamic studies demonstrated its activity in inhibiting breast cancer cell metastasis. This study examined the pharmacokinetics, absolute bioavailability, and tissue distribution of CNF2 in rats, and combined computer-aided technology to predict the druggability of CNF2. The binding site of CNF2 and the breast cancer target human epidermal growth factor receptor-2 (HER2) were examined with molecular docking technology. Next, ACD/Percepta software was used to predict the druggability of CNF2 based on the quantitative structure-activity relationship (QSAR). Finally, a simple and effective HPLC method was used to determine plasma pharmacokinetics and tissue distribution of CNF2 in rats. Prediction and experimental results show that compared with the positive control HER2 inhibitor SYR127063, CNF2 has a stronger binding affinity with HER2, suggesting that its efficacy is stronger; and the structure of CNF2 complies with the Lipinski's Rule of Five and has good drug-likeness. The residence time of CNF2 in rats is less than 4 h, and the metabolic rate is relatively fast; But the absolute bioavailability of CNF2 in rats was 6.6%, mainly distributed in the stomach, intestine, and lung tissues, where the CNF2 contents were 401.20, 144.01, and 245.82 µg/g, respectively. This study constructed rapid screening and preliminary evaluation of active compounds, which provided important references for the development and further research of such compounds.

Nadifloxacin, mometasone furoate and miconazole nitrate are formulated together as a topical antifungal dosage form. In this work, a reversed-phase ultra-performance liquid chromatographic method coupled with a diode array detector (RP-UPLC-DAD) was developed and validated to determine nadifloxacin, mometasone furoate and miconazole nitrate simultaneously in their bulk powder, in pharmaceutical preparation and in spiked human plasma samples. Separation was achieved on an ACQUITY UPLC C18 column of 2.2 μm particle size (2.1 × 100 mm) via isocratic elution using a mobile phase consisting of methanol, acetonitrile and water with ratio (50:20:30; v/v/v) and 0.1 g ammonium acetate, then pH was adjusted to (7.00) using acetic acid, flow rate 0.6 mL/min, temperature 30°C and UV detection at 220 nm. The method is linear in a range from 5 to 400 μg/mL for both nadifloxacin and miconazole nitrate and from 20 to 500 μg/mL for mometasone furoate. The method was validated according to the ICH guidelines then applied successfully to determine the mentioned drugs in their pharmaceutical preparation and spiked human plasma samples. For plasma samples, the results showed that the method can determine nadifloxacin, mometasone furoate and miconazole nitrate in human plasma samples with high accuracy and precision., (© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objective: To characterize the pharmacokinetics of vatinoxan in isoflurane-anesthetized cats., Study Design: Prospective experimental study., Animals: A group of six adult healthy male neutered cats., Methods: Cats were anesthetized using isoflurane in oxygen. Venous catheters were placed to administer the drug and sample blood. Vatinoxan, 1 mg kg -1 , was administered intravenously over 5 minutes. Blood was sampled before and at various times during and up to 8 hours after vatinoxan administration. Plasma vatinoxan concentration was measured using liquid chromatography/tandem mass spectrometry. Compartment models were fitted to the time-concentration data using population methods and nonlinear mixed effect modeling., Results: A three-compartment model best fitted the data. Typical value (% interindividual variability) for the three volumes (mL kg -1 ), the metabolic clearance and two distribution clearances (mL minute -1 kg -1 ) were 34 (55), 151 (35), 306 (18), 2.3 (34), 42.6 (25) and 5.6 (0), respectively. Hypotension increased the second distribution clearance to 10.6., Conclusion and Clinical Relevance: The pharmacokinetics of vatinoxan in anesthetized cats were characterized by a small volume of distribution and a low clearance. An intravenous bolus of 100 μg kg -1 of vatinoxan followed by constant rate infusions of 55 μg kg -1 minute -1 for 20 minutes, then 22 μg kg -1 minute -1 for 60 minutes and finally 10 μg kg -1 minute -1 for the remainder of the infusion time is expected to maintain the plasma concentration within 90%-110% of the plasma vatinoxan concentration previously shown to attenuate the cardiovascular effects of dexmedetomidine (25 μg kg -1 ) in conscious cats., (Copyright © 2019 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To quantify the peripheral selectivity of vatinoxan (L-659,066, MK-467) in dogs by comparing the concentrations of vatinoxan, dexmedetomidine and levomedetomidine in plasma and central nervous system (CNS) tissue after intravenous (IV) coadministration of vatinoxan and medetomidine., Study Design: Experimental, observational study., Animals: A group of six healthy, purpose-bred Beagle dogs (four females and two males) aged 6.5 ± 0.1 years (mean ± standard deviation)., Methods: All dogs were administered a combination of medetomidine (40 μg kg -1 ) and vatinoxan (800 μg kg -1 ) as IV bolus. After 20 minutes, the dogs were euthanized with an IV overdose of pentobarbital (140 mg kg -1 ) and both venous plasma and CNS tissues (brain, cervical and lumbar spinal cord) were harvested. Concentrations of dexmedetomidine, levomedetomidine and vatinoxan in all samples were quantified by liquid chromatography-tandem mass spectrometry and data were analyzed with nonparametric tests with post hoc corrections where appropriate., Results: All dogs became deeply sedated after the treatment. The CNS-to-plasma ratio of vatinoxan concentration was approximately 1:50, whereas the concentrations of dexmedetomidine and levomedetomidine in the CNS were three- to seven-fold of those in plasma., Conclusions and Clinical Relevance: With the doses studied, these results confirm the peripheral selectivity of vatinoxan in dogs, when coadministered IV with medetomidine. Thus, it is likely that vatinoxan preferentially antagonizes α 2 -adrenoceptors outside the CNS., (Copyright © 2019 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

1. Cytisine, a partial agonist for the α 4 β 2 -nAChR, is used as a smoking cessation medication. Cytisine's current dosing is complex and involves taking 1.5 mg several times a day. The aim of this study was to explore the effect of dose on the pharmacokinetics and safety of cytisine after a single dose in healthy adult smokers. 2. Participants were assigned to one of three groups ( n  = 6 in each group) to receive a single oral dose of 1.5, 3 or 4.5 mg of cytisine. Blood samples were collected up to 24 h post dose. Pulse, blood pressure and respiratory rate were measured. Adverse effects were recorded. 3. Cytisine reached peak plasma concentration 1-2 h post dose in all participants irrespective of dose, with no dose-dependent changes in the elimination phase. Mean (SD) cytisine exposure (AUC 0-24h ) were 81.9 (15.8), 181.9 (40.8) and 254.5 (48.1) ng.h/mL following 1.5, 3 and 4.5 mg, respectively. 4. Cytisine appears to have predictable pharmacokinetics following a single dose of up to 4.5 mg and may be safe given as a single 4.5 mg dose, which is threefold greater than the recommended dose taken at one time. This study is registered in ClinicalTrials.gov (ID:NCT02585024).

Da-Huang-Xiao-Shi decoction (DHXSD), a traditional Chinese medicinal formula, has been used mainly to treat jaundice for more than 1700 years in China. In this study, we developed a rapid, sensitive, and accurate LC-MS/MS method to simultaneously determine multiple, potentially bioactive compounds of DHXSD, including five alkaloids (berberine, phellodendrine, palmatine, jatrorrhizine, and magnoflorine), five anthraquinones (rhein, aloe-emodin, emodin, chrysophanol, and physcion), two iridoid glycosides (geniposide and genipin 1-gentiobioside), and one iridoid aglycone (genipin) in rat plasma. Plasma samples collected from rats were treated immediately with 5% acetic acid to avoid the degradation of genipin. After protein precipitation with acetonitrile containing 5% acetic acid, the compounds were reconstituted in acetonitrile-water (50:50, v/v) solution containing 6.5% formic acid and separated on the ACQUITY™ UPLC BEH C 18 column (2.1 × 100 mm; 1.7 μm) using a mobile phase composed of 2 mM ammonium formate in water (solvent A) and acetonitrile (solvent B) at a flow rate of 0.3 mL/min. Quantitation was performed on a Triple Quand 5500 tandem mass spectrometer coupled with an electrospray ionization (ESI) source. Multiple reaction monitoring (MRM) was used to quantify compounds in positive and negative ion modes. The method validation results showed that the specificity, linearity, precision and accuracy, recovery, matrix effect, and stability of the 13 compounds met the requirements for their quantitation in biological samples. This newly established method was successfully used in a pharmacokinetic study on rats orally treated with DHXSD. Besides, glucuronide and sulfate metabolites were also determined in rat plasma after hydrolysis. This is the first method developed for the simultaneous quantification of multiple compounds of DHXSD in vivo. Our study provides relevant information on the pharmacokinetics of DHXSD and the relationship between the compounds of DHXSD and their therapeutic effects., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A constant rate infusion (CRI) of medetomidine is used to balance equine inhalation anesthesia, but its cardiovascular side effects are a concern. This experimental crossover study aimed to evaluate the effects of vatinoxan (a peripheral α2-adrenoceptor antagonist) on cardiorespiratory and gastrointestinal function in anesthetized healthy horses. Six horses received medetomidine hydrochloride 7μg/kg IV alone (MED) or with vatinoxan hydrochloride 140μg/kg IV (MED+V). Anesthesia was induced with midazolam and ketamine and maintained with isoflurane and medetomidine CRI for 60min. Heart rate, carotid and pulmonary arterial pressures, central venous pressure, cardiac output and arterial and mixed venous blood gases were measured. Selected cardiopulmonary parameters were calculated. Plasma drug concentrations were determined. Fecal output was measured over 24h. For statistical comparisons, repeated measures analysis of covariance and paired t-tests were applied. Heart rate decreased slightly from baseline in the MED group. Arterial blood pressures decreased with both treatments, but significantly more dobutamine was needed to maintain normotension with MED+V (P=0.018). Cardiac index (CI) and oxygen delivery index (DO 2 I) decreased significantly more with MED, with the largest difference observed at 20min: CI was 39±2 and 73±18 (P=0.009) and DO 2 I 7.4±1.2 and 15.3±4.8 (P=0.014)mL/min/kg with MED and MED+V, respectively. Fecal output or plasma concentrations of dexmedetomidine did not differ between the treatments. In conclusion, premedication with vatinoxan induced hypotension, thus its use in anesthetized horses warrants further studies. Even though heart rate and arterial blood pressures remained clinically acceptable with MED, cardiac performance and oxygen delivery were lower than with MED+V., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objectives The objectives were to evaluate the pharmacokinetics (PK) of subcutaneous (SC) and intravenous (IV) dolasetron and the pharmacodynamics (PD) of SC dolasetron in healthy cats. Methods Five cats with unremarkable complete blood count, serum biochemistry and urinalyses were utilized. In the PK study, cats received 0.8 mg/kg SC and IV dolasetron in a crossover format. Serum samples were obtained via a jugular catheter at 0, 0.25, 0.5, 1, 2, 4, 8, 12, 24, 36 and 48 h after the administration of dolasetron. Dolasetron and the active metabolite hydrodolasetron were measured using liquid chromatography/tandem mass spectrometry. Non-compartmental PK analysis was performed. In the PD study, SC dolasetron (0.8 mg/kg and 1.0 mg/kg) and saline were administered 30 mins prior to administration of 0.44 mg/kg intramuscular xylazine in a randomized three-way crossover. Number of emetic events, lip licks, time to onset of emesis and visual nausea score were scored by a blinded observer. Results In the PK study, dolasetron was quickly metabolized to the active metabolite hydrodolasetron, limiting assessment of dolasetron PK parameters. Median (range) PK parameters for IV hydrodolasetron were as follows: maximum serum concentration (C max ) 116 ng/ml (69-316 ng/ml), time to maximum concentration (T max ) 0.5 h (0.3-0.5 h), half-life 3.3 h (2.9-7.2 h) and area under the curve until the last measurable concentration (AUC last ) 323 h/ng/ml (138-454 h/ng/ml). Median (range) PK parameters for SC hydrodolasetron were as follows: C max 67.9 ng/ml (60.4-117 ng/ml), T max 0.5 h (0.5-1.0 h), half-life 3.8 h (2.9-5.3 h) and AUC last 437 h/ng/ml (221.5-621.8 h/ng/ml). There was no significant difference in exposure to hydrodolasetron between the routes of administration. With regard to PD, when dolasetron was administered prior to xylazine, there was no significant difference in the mean number of emetic events, lip licks, time to onset of emesis or visual nausea score when compared with saline. Conclusions and relevance Administration of 0.8 mg/kg dolasetron does not maintain serum concentrations of active metabolite for 24 h. Administration of dolasetron at 0.8 mg/kg and 1 mg/kg did not prevent xylazine-induced vomiting. Additional feline dose studies are needed to determine if a higher dose is efficacious.

Objective: We determined the possible effects of a peripherally acting α 2 -adrenoceptor antagonist, MK-467, on the absorption of intramuscularly (IM) coadministered medetomidine, butorphanol and midazolam., Study Design: Randomized, experimental, blinded crossover study., Animals: Six healthy Beagle dogs., Methods: Two IM treatments were administered: 1) medetomidine hydrochloride (20 μg kg -1 ) + butorphanol (100 μg kg -1 ) + midazolam (200 μg kg -1 ; MBM) and 2) MBM + MK-467 hydrochloride (500 μg kg -1 ; MBM-MK), mixed in a syringe. Heart rate was recorded at regular intervals. Sedation was assessed with visual analog scales (0-100 mm). Drug concentrations in plasma were analyzed with liquid chromatography-tandem mass spectrometry, with chiral separation of dex- and levomedetomidine. Maximum drug concentrations in plasma (C max ) and time to C max (T max ) were determined. Paired t-tests, with Bonferroni correction when appropriate, were used for comparisons between the treatments., Results: Data from five dogs were analyzed. Heart rate was significantly higher from 20 to 90 minutes after MBM-MK. The T max values for midazolam and levomedetomidine (mean ± standard deviation) were approximately halved with coadministration of MK-467, from 23 ± 9 to 11 ± 6 minutes (p = 0.049) for midazolam and from 32 ± 15 to 18 ± 6 minutes for levomedetomidine (p = 0.036), respectively., Conclusions and Clinical Relevance: MK-467 accelerated the absorption of IM coadministered drugs. This is clinically relevant as it may hasten the onset of peak sedative effects., (Copyright © 2018 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Oxymatrine (OMT) and matrine (MT) are two naturally occurring alkaloids, both of them provide anti-hepatitis effects. However OMT effect was heavily limited due to its low bioavailability, short half-life and whole body distribution. Herein, we investigated hydrogenated soybean phosphatidylcholine (HSPC) liposomes made by pH gradient active loading to understand the improved hepatoprotective effect mechanisms. Pharmacokinetics researches demonstrated the half-life time of OMT HSPC liposomes was 17.10h in mice. Compared with OMT solution, AUC (0-8) of OMT and MRT (0-8) of MT had been increased 11.8 fold and 14.3 fold in HSPC liposomes. Moreover, tissue distribution revealed the relative AUC s of total alkaloids in liver of OMT HSPC liposomes was as 4.18 times as that of OMT solution. Our data suggested that pathological topical necrosis and mild vacuolar degeneration of liver progressively returned to normal, and serum level of alanine-aminotransferase (ALT) and aspartate-aminotransferase (AST) were significantly reduced after treating with OMT HSPC liposomes in acute liver injury mice induced by CCl 4 . Pharmacokinetics, biodistribution and pathological researches manifested that HSPC liposomes served as an ideal and potential oxymatrine liver target carrier to prolong OMT retention time and maintain high therapeutically level in liver., (Copyright © 2017. Published by Elsevier B.V.)

A sensitive and rapid ultra-performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS/MS) method was developed for the simultaneous analysis of anemoside B4, phellodendrine, berberine, palmatine, obakunone, esculin, esculetin, toosendanin (IS 1 of anemoside B4), tetrahydropalmatine (IS 2 of phellodendrine, berberine, palmatine and obakunone) and scopoletin (IS 3 of esculin and esculetin) and to compare the pharmacokinetics of these active ingredients in normal and ulcerative colitis rats. After methanol deproteinization, solvents were evaporated at 40°C under a gentle stream of nitrogen. Chromatography was performed using a C18 column with a gradient elution of 0.1% aqueous formic acid and acetonitrile at 0.4ml/min. Detection and measurement were performed on a 4000 QTRAP UPLC-MS/MS system from AB Sciex in the multiple reaction monitoring (MRM) mode. Phellodendrine, berberine, palmatine, obakunone, esculin, esculetin, tetrahydropalmatine (IS 2 ) and scopoletin (IS 3 ) were monitored under positive ionization conditions. Anemoside B4, and toosendanin (IS 1 ) were monitored under negative ionization conditions. The optimized mass transition ion-pairs (m/z) were 1221.1/750.7 for anemoside B4, 343.2/193.2 for phellodendrine, 337.1/321.0 for berberine, 353.0/336.9 for palmatine, 455.1/161.1 for obakunone, 341.2/179.2 for esculin, 179.1/123.0 for esculetin, 573.4/531.4 for toosendanin (IS 1 ), 356.2/192.2 for tetrahydropalmatine (IS 2 ) and 193.0/133.1 for scopoletin (IS 3 )., (Copyright © 2016 Elsevier B.V. All rights reserved.)

This study characterized the pharmacokinetics of dexmedetomidine, MK-467, and their combination following intravenous bolus administration to cats. Seven 6- to-year-old male neutered cats, weighting 5.1 ± 0.7 kg, were used in a randomized, crossover design. Dexmedetomidine [12.5 (D12.5) and 25 (D25) μg/kg], MK-467 [300 μg/kg (M300)] or dexmedetomidine (25 μg/kg) and MK-467 [75, 150, 300 or 600 μg/kg-only the plasma concentrations in the 600 μg/kg group (D25M600) were analyzed] were administered intravenously, and blood was collected until 8 hours thereafter. Plasma drug concentrations were analyzed using liquid chromatography/mass spectrometry. A two-compartment model best fitted the data. Median (range) volume of the central compartment (mL/kg), volume of distribution at steady state (mL/kg), clearance (mL min/kg) and terminal half-life (min) were 342 (131-660), 829 (496-1243), 14.6 (9.6-22.7) and 48 (40-69) for D12.5; 296 (179-982), 1111 (908-2175), 18.2 (12.4-22.9) and 52 (40-76) for D25; 653 (392-927), 1595 (1094-1887), 22.7 (18.5-36.4) and 48 (35-60) for dexmedetomidine in D25M600; 117 (112-163), 491 (379-604), 3.0 (2.0-4.5) and 122 (99-139) for M300; and 147 (112-173), 462 (403-714), 2.8 (2.1-4.8) and 118 (97-172) for MK-467 in D25M600. MK-467 moderately but statistically significantly affected the disposition of dexmedetomidine, whereas dexmedetomidine minimally affected the disposition of MK-467., (© 2016 John Wiley & Sons Ltd.)

Phellodendrine, a quaternary ammonium alkaloid extracted from the dried bark of Phellodendrom chinensis Schneid and Phellodendrom amurense Rupr, has the effect of suppressing cellular immune response, reducing blood pressure and antinephritis. However, few investigations have been conducted for the pharmacokinetic study of phellodendrine. Thus, a rapid, simple and reliable ultra-high performance liquid chromatography-tandem quadrupole mass spectrometry (UHPLC-QQQ MS/MS) method has been established for quantification of phellodendrine in rat plasma and tissues by using magnoflorine as internal standard. The chromatographic separation was achieved on an Agilent ZORBAX SB-C18 column (4.6mm×50mm, 1.8μm) by gradient elution using 0.1% aqueous formic acid (A) and methanol (B). Triple quadrupole mass detection with multiple reaction monitoring mode was used to monitor the ion transitions, at m/z 342.20→192.20 for phellodendrine and m/z 342.20→58.20 for internal standard, respectively. The developed method was fully validated and successfully applied to the pharmacokinetics and tissue distribution study of phellodendrine after intravenous administration. The lower limits of quantification were 0.5ng/mL for plasma samples, 2.5ng/g for brain and 1ng/g for other tested tissues. Precisions and accuracy values were within the Food and Drug Administration acceptance criteria, the recovery and matrix effects were between 87.8-113.5%. The area under the curve (AUC0-t) ranged from 15.58 to 57.41mg/L min and Cmax were between 1.63-4.93mg/L. The results showed that phellodendrine was eliminated in 120min in plasma and most of tissues and the highest concentrations of phellodendrine were found in the kidney. This study may provide a basis for the further study of phellodendrine., (Copyright © 2016 Elsevier B.V. All rights reserved.)

This study determined the unbound fraction of the peripheral α2 -adrenoceptor antagonist MK-467 alone and combined with medetomidine. MK-467 (0.1, 1 and 10 μm) was incubated in canine plasma with and without medetomidine (molar ratio 20:1), with human serum albumin (HSA) and with α1-acid glycoprotein (AGP). Rapid equilibrium dialysis was used for the measurement of protein binding. All samples were analysed by liquid chromatography and tandem mass spectrometry to obtain the unbound fraction (fu ) of MK-467. Unbound fractions (fu ) of MK-467 in canine plasma (mean ± standard deviation) were 27.6 ± 3.5%, 26.6 ± 0.9% and 42.4 ± 1.2% at 0.1, 1.0 and 10 μm concentrations, respectively. In the presence of medetomidine, fu were 27.5 ± 0.4%, 26.6 ± 0.9% and 41.0 ± 2.4%. The fu of MK-467 in HSA were 50.1 ± 2.5% at 0.1 μm, 49.4 ± 1.2% at 1.0 μm and 56.7 ± 0.5% at 10 μm. fu of MK-467 in AGP was 56.3 ± 3.7% at 0.1 μm, 54.6 ± 5.6% at 1.0 μm and 65.3 ± 0.4% at 10 μm. Protein binding of MK-467 was approximately 70% between 0.1 and 1.0 μm. Medetomidine had no apparent effect on the protein binding of MK-467., (© 2016 John Wiley & Sons Ltd.)

Cytisine, an α4 β2 nicotinic receptor partial agonist, is a plant alkaloid that is commercially extracted for use as a smoking cessation medication. Despite its long history of use, there is very little understanding of the pharmacokinetics of cytisine. To date, no previous studies have reported cytisine concentrations in humans following its use as a smoking cessation agent. A high performance liquid chromatography-ultraviolet (HPLC-UV) method was developed and validated for analysis of Tabex® and nicotine-free oral strips, two commercial products containing cytisine. A sensitive liquid chromatography-mass spectrometry (LC-MS) method was developed and validated for the quantification of cytisine in human plasma and for the detection of cytisine in urine. Single-dose pharmacokinetics of cytisine was studied in healthy smokers. Subjects received a single 3 mg oral dose administration of cytisine. Cytisine was detected in all plasma samples collected after administration, including 15 min post-dose and at 24 h. Cytisine was renally excreted and detected as an unchanged drug. No metabolites were detected in plasma or urine collected in the study. No adverse reactions were reported., (Copyright © 2014 John Wiley & Sons, Ltd.)

In this work, a sensitive and selective UPLC-MS/MS method for determination of N-methylcytisine in rat plasma is developed. After addition of hordenine as an internal standard (IS), protein precipitation by acetonitrile-methanol (9:1, v/v) was used to prepare samples. Chromatographic separation was achieved on a UPLC BEH HILIC (2.1 mm×100mm, 1.7μm) with acetonitrile (containing 10mM ammonium formate) and water (containing 0.1% formic acid and 10mM ammonium formate) as the mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reaction monitoring (MRM) mode was used for quantification using target fragment ions m/z 205.1→58.0 for N-methylcytisine, and m/z 166.1→121.0 for IS. Calibration plots were linear throughout the range 2-2000ng/mL for N-methylcytisine in rat plasma. Mean recoveries of N-methylcytisine in rat plasma ranged from 86.1% to 94.8%. RSD of intra-day and inter-day precision were both<13%. The accuracy of the method was between 94.5% and 109.4%. The method was successfully applied to pharmacokinetic study of N-methylcytisine after either oral or intravenous administration. For the first time, the absolute bioavailability of N-methylcytisine was reported as high as 55.5%., (Copyright © 2015 Elsevier B.V. All rights reserved.)

A rapid, sensitive and selective high-performance liquid chromatography-tandem mass spectrometric method (HPLC-MS) has been developed and validated for the simultaneous determination of 14-thienyl methylene matrine (TMM) and matrine (MT) in rat plasma in the present study. The analytes were separated on a C18 column (1.9 μm, 2.1 mm × 100 mm) with a security guard C18 column (5 μm, 2.1 mm × 10 mm) and a triple-quadrupole mass spectrometry equipped with an electrospray ionization (ESI) source was applied for detection. With pseudoephedrine hydrochloride as internal standard, sample pretreatment involved in a one-step protein precipitation with isopropanol:ethyl acetate (v/v, 20:80). The method was linear over the concentration ranges of 5-1000 ng/ml for TMM and 10-2000 ng/ml for MT. The intra-day and inter-day relative standard deviations (RSD) were less than 15% and the relative errors (RE) were all within 15%. The proposed method enables unambiguous identification and quantification of TMM and MT in vivo. This was the first report on determination of the TMM and MT in rat plasma after oral administration of TMM. The results provided a meaningful basis for evaluating the clinical applications of the medicine., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Kushen-Gancao Decoction (KGD) is a classic traditional Chinese herb combination in treating viral hepatitis and chronic liver diseases. This study aims to investigate the pharmacokinetic (PK) study of matrine (MT), oxymatrine (OMT), glycyrrhizic acid (GL) and glycyrrhetinic acid (GA) following oral administration of KGD in rats. A rapid, sensitive and reliable HPLC-MS/MS method was successfully developed for the simultaneous determination of MT, OMT, GL and GA in rat plasma. A Inertsil C18 analytical column was used with a gradient mobile phase system of methanol-ammonium acetate (5mM) with a flow rate of 0.5 mL/min. The analysis was performed on a positive and negative ionization electrospray mass spectrometer via multi reaction monitoring (MRM). Linear calibration curves were obtained for the following concentration range: 10-5000 ng/mL for MT, OMT and GL, 50-15,000 ng/mL for GA in rat plasma (R(2)>0.99). The lower limit of quantification (LLOQ) was 5 ng/mL (MT, OMT and GL) and 20 ng/mL (GA). The intra- and inter-day accuracies ranged from -7.91 to 9.10% and precisions (RSD) were within 15%. The analytes were found to be stable under short-term temperature conditions, post-preparative temperature conditions, and after three freeze-thaw cycles conditions. The validated method was successfully applied to a pharmacokinetic study in rats after oral administration of KGD., (Copyright © 2014 Elsevier B.V. All rights reserved.)

A rapid, sensitive and selective high-performance liquid chromatography mass spectrometric method has been developed and validated for the simultaneous determination of oxymatrine and its active metabolite matrine in human plasma after administration of oxymatrine oral solution. Analytes were extracted from the plasma by liquid-liquid extraction with chloroform. The chromatographic separation was accomplished on a Venusil C18 column (150 mm × 4.6 mm, 5 μm) protected by a C18 guard column (4.0 mm × 2.0 nm; Phenomenex, Torrance, CA, USA). Analytes were detected on a single quadruple mass spectrometer by selected ion monitoring mode via electrospray ionization source. The assay had a lower limit of quantification of 1.5 ng·mL(-1) for oxymatrine and 3 ng·mL(-1) for matrine in plasma. The calibration curves were linear in the measured range. The overall precision and accuracy for all concentrations of quality controls and standards were within ±15%. The proposed method enabled unambiguous identification and quantification of oxymatrine and its active metabolite matrine in vivo. The results provided a meaningful basis for evaluating the clinical applications of the oxymatrine oral solution., (Copyright © 2013. Published by Elsevier B.V.)

Objective: To investigate plasma drug concentrations and the effect of MK-467 (L-659'066) on sedation, heart rate and gut motility in horses sedated with intravenous (IV) detomidine., Study Design: Experimental randomized blinded crossover study., Animals: Six healthy horses., Methods: Detomidine (10 μg kg(-1) IV) was administered alone (DET) and in combination with MK-467 (250 μg kg(-1) IV; DET + MK). The level of sedation and intestinal sounds were scored. Heart rate (HR) and central venous pressure (CVP) were measured. Blood was collected to determine plasma drug concentrations. Repeated measures anova was used for HR, CVP and intestinal sounds, and the Student's t-test for pairwise comparisons between treatments for the area under the time-sedation curve (AUCsed ) and pharmacokinetic parameters. Significance was set at p < 0.05., Results: A significant reduction in HR was detected after DET, and HR was significantly higher after DET + MK than DET alone. No heart blocks were detected in any DET + MK treated horses. DET + MK attenuated the early increase in CVP detected after DET, but later the CVP decreased with both treatments. Detomidine-induced intestinal hypomotility was prevented by MK-467. AUCsed was significantly higher with DET than DET + MK, but maximal sedations scores did not differ significantly between treatments. MK-467 lowered the AUC of the plasma concentration of detomidine, and increased its volume of distribution and clearance., Conclusions and Clinical Relevance: MK-467 prevented detomidine induced bradycardia and intestinal hypomotility. MK-467 did not affect the clinical quality of detomidine-induced sedation, but the duration of the effect was reduced, which may have been caused by the effects of MK-467 on the plasma concentration of detomidine. MK-467 may be useful clinically in the prevention of certain peripheral side effects of detomidine in horses., (© 2013 The Authors. Veterinary Anaesthesia and Analgesia © 2013 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.)

In this study, we evaluated chemopreventive efficacy of Antitumor B, a Chinese herbal mixture of six plants (Sophora tonkinensis, Polygonum bistorta, Prunella vulgaris, Sonchus arvensis L., Dictamnus dasycarpus, and Dioscorea bulbifera) on the development of 4-nitroquinoline-1-oxide (4NQO) induced oral squamous cell carcinomas in A/J mice. Antitumor B, delivered through diet, inhibited 4NQO-induced oral cancer development by 59.19%. The reduction of cell proliferation appears to be associated with efficacy of Antitumor B against 4NQO-induced oral cancer in A/J mice. The expression of epidermal growth factor receptor (EGFR) and phosphorylated EGFR (Tyr1173) were down-regulated by Antitumor B. Tissue distribution of Antitumor B was determined using obacunone, matrine, and maackiain as marker chemicals. We found significant amounts of obacunone, matrine, and maackiain in the blood after 1-wk treatment. The concentrations of these three compounds did not increase further at 18  wk, suggesting that plasma concentrations had reached a steady-state level at 1  wk. There was no significant body weight loss and there was no other obvious sign of toxicity in Antitumor B-treated mice. These results suggest that Antitumor B is a promising agent for human oral cancer chemoprevention., (Copyright © 2011 Wiley Periodicals, Inc.)

A high-performance liquid chromatographic method coupled with electrospray mass spectrometry was developed for the simultaneous determination of dolasetron and its major metabolite, hydrodolasetron, in human plasma. A new sample pretreatment method, i.e., salt induced phase separation extraction (SIPSE), was proposed and compared with four other methods, i.e., albumin precipitation, liquid-liquid extraction, hydrophobic solvent-induced phase separation extraction and subzero-temperature induced phase separation extraction. Among these methods, SIPSE showed the highest extraction efficiency and the lowest matrix interferences. The extraction recoveries obtained from the SIPSE method were all more than 96% for dolasetron, hydrodolasetron and ondansetron (internal standard). The SIPSE method is also very fast and easy because protein precipitation, analyte extraction and sample cleanup are combined into one simple process by mixing acetonitrile with plasma and partitioning with 2 mol/L sodium carbonate aqueous solution. The correlation coefficients of the calibration curves were all more than 0.997, in the range of 7.9-4750.0 ng/mL and 4.8-2855.1 ng/mL for dolasetron and hydrodolasetron, respectively. The limits of quantification were 7.9 and 4.8 ng/mL for dolasetron and hydrodolasetron, respectively. The intra-day and inter-day repeatability were all less than 10%. The method was successfully applied to the pharmacokinetic study of dolasetron.

Six healthy laboratory Beagles were treated IV with 10 μg/kg dexmedetomidine (DEX) or 10 μg/kg dexmedetomidine combined with 500 μg/kg MK-467 in the same syringe (DMK) in a randomised cross-over design with a 14 day washout. Blood was collected immediately before treatment and 35, 60 and 120 min post-injection through a central venous catheter. The plasma concentrations of glucose, insulin, non-esterified free fatty acids (NEFAs), lactate and cortisol were determined. A repeated-measures ANOVA test was used to compare treatments and effects for each sample time point. Significant differences between treatments were found for plasma glucose (P=0.037) and insulin (P=0.009). DEX significantly increased plasma glucose at 120 min, but reduced plasma insulin at 35 and 60 min. NEFA decreased for both treatments at 35 min. This reduction was transient for DMK, whereas it persisted during the follow up period for DEX. Plasma lactate concentrations increased at 35 and 60 min with DEX. Neither treatment altered plasma cortisol concentrations. The addition of MK-467 to dexmedetomidine prevented or abolished most metabolic changes in healthy Beagles., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Objective: To investigate the effect of ceftiofur hydrochloride on the pharmacokinetics of matrine in rats., Method: The rats were divided into two groups: one group was administrated with matrine only (control group) and the other was administrated with matrine in combination with ceftiofur hydrochloride. HPLC-UV method was used for determining the plasma concentration of matrine in both groups. The pharmacokinetic parameters were calculated from the plasma concentration-time data using the DAS 2. 1. 1 software program., Result: The main pharmacokinetic parameters for the control group were C(max) = 21.113 9 mg x L(-1), T(max) = 0.75 h, t1/2alpha = 1.34 h, t1/2beta = 3.509 h, AUC(0-t) = 90.984 mg x h(-1) x L(-1) and AUC(0-inifinity) = 100.346 mg x h(-1) x L(-1), and the data for the combination group were C(max) = 11.707 mg x L(-1), T(max) = 0.917 h, t1/2alpha = 1.598 h, t1/2beta = 3.247 h, AUC(0-t) = 53.28 mg x h(-1) x L(-1) and AUC(0-inifinity) = 60.035 mg x h(-1) x L(-1)., Conclusion: The plasma concentration of matrine and bioavailability in combination group were significantly lower than those of the control group. In combination group, matrine had a higher clearance and volume of distribution in the central compartments, as well as a lower volume of distribution in the peripheral compartments.

The purpose of this research was to develop a sensitive and reproducible UPLC-MS/MS method to analyze matrine, an anticancer compound, and to use it to investigate its biopharmaceutical and pharmacokinetic behaviors in rats. A sensitive and fast UPLC-MS/MS method was successfully applied to determine matrine in rat plasma, intestinal perfusate, bile, microsomes, and cell incubation media. The absolute oral bioavailability of matrine is 17.1+/-5.4% at a dose of 2mg/kg matrine. Matrine at 10microM was shown to have good permeability (42.5x10(-6)cm/s) across the Caco-2 cell monolayer, and the ratio of P(A-B) to P(B-A) was approximately equal to 1 at two different concentrations (1 and 10microM). Perfusion study showed that matrine displayed significant differences (P<0.05) in permeability at different intestinal regions. The rank order of permeability was ileum (highest, P(w)=6.18), followed by colon (P(w)=2.07), duodenum (P(w)=0.61) and jejunum (P(w)=0.52). Rat liver microsome studies showed that CYP and UGTs were not involved in matrine metabolism. In conclusion, a sensitive and reliable method capable of measuring matrine in a variety of matrixes was developed and successfully used to determine absolute oral bioavailability of matrine in rats, transport across Caco-2 cell monolayers, absorption in rat intestine, and metabolism in rat liver microsomes., (Copyright 2009 Elsevier B.V. All rights reserved.)

Background: Multivesicular liposomes (MVLs), uncoated and coated with N-trimethyl chitosan (TMC), have been studied for their potential use for drug delivery by the oral route., Method: Synthesized TMC was characterized by infrared spectroscopy, revealing the presence of trimethyl groups, and by proton nuclear magnetic resonance spectroscopy, allowing the calculation of the degree of substitution quaternization (70.2%). Oxymatrine (OM), a natural quinolizidine alkaloid used clinically for treating hepatitis B, was chosen as a model drug. The surface-modified MVLs and uncoated MVLs were characterized in vitro in terms of their shape, size, zeta potential, entrapment efficiency, coating efficiency, the stability of MVLs in polymer suspension, and the stability in simulated gastric and intestinal fluids., Results: In vivo, the area under the plasma concentration-time curve obtained from the pharmacokinetics study of TMC-coated MVLs was found to be about 3.26- and 1.96-fold higher than that of OM solution and uncoated MVLs, respectively., Conclusion: TMC-coated MVLs can be considered as a potential carrier for oral drug administration.

A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the determination of matrine in human plasma extracted by isopropanol:ethyl acetate (v/v, 5:95). Rapid chromatographic separation was achieved in the mobile phase composition of 5-mM aqueous ammonium acetate and acetonitrile (v/v, 70:30) with a flow rate of 0.20ml/min. Detection was carried out using positive-ion electrospray tandem mass spectrometry on a Sciex API3000. The method was accurate, specific and sensitive for the analysis of matrine in human plasma in the concentration range of 5-2000ng/ml, when huperzine A was used as internal standard. The method facilitated a clinical pharmacokinetic study after oral administration of a single dose of matrine soft gelatin capsules (100, 200 and 400mg) in a three-period crossover design. Dose-related linear trends were observed for the AUC(0-t) and the C(max) of matrine. The t(1/2) and the T(max) of matrine were independent of the administered doses.

Objective: To determine the concentration of matrine in rats plasma and tissue and study the pharmacokinetics and tissues distribution of matrine solution (MS), regular matrine liposome (ML) and stealth matrine liposome (LML) after the intravenous administration at a single dose of 15 mg x kg(-1) to rats., Method: Reversed-phase HPLC was used to determine matrine concentration in rats plasma and tissues., Result: The concentration-time curves of MS, ML and LML were fitted to a two-compartment model. The terminal half-life of LML was 2.7-fold higher than MS and 2-fold higher than ML. The area under the plasma concentration curve (AUC) of LML was 63-fold higher than MS and 2.3-fold higher than ML. Tissues distribution results proved that the area under the plasma concentration curve of LML was significantly different from ML and MS (P<0.05). The area under the liver and spleen curve of LML was significantly different from ML (P<0.05). The ratio between the area under the curve of plasma and the area under the curve of reticulo-endothelial system (Blood/RES) of LML was 5.4-fold higher than ML., Conclusion: Our present studies demonstrate that, compared to MS and ML, LML significantly alters its pharmacokinetics in plasma and tissues targeting.

Oxymatrine (OMT) and matrine (MT) are the major quinolizidine alkaloids found in certain Sophora plants, which have been extensively used in China for the treatment of viral hepatitis, cancer, cardiac diseases and skin diseases (such as atopic dermatitis and eczema). A precise, sensitive and high throughput LC-MS/MS was developed to determine OMT and its metabolite MT in rat blood and dermis collected using microdialysis technique. Microdialysis probes were inserted into the jugular vein/right atrium and dermis of Wistar rats, and 3% OMT gel (1g) was administered via topical application. The samples were collected and then injected into the LC-MS/MS system after adding the internal standard (codeine, CDN). Chromatographic separation was achieved in a run time of 2min on a reversed phase short-column (50mmx2.1mm, 3.5microm). The mobile phase for column separation was methanol-ammonium formate (pH 5.0; 25mM) (70:30, v/v) with a flow rate of 0.3mL/min. A diverter valve was installed post-LC column for desalting. 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 OMT, MT and IS was m/z 265.0-->247.3, 249.1-->148.3 and 300.0-->215.2, respectively. The lower limit of quantification (LLOQ) for OMT and MT was 0.5ng/mL. The calibration curves were linear over the range of 0.5-1000ng/mL for OMT and MT with a coefficient of determination >0.999. This selective and sensitive method is useful for the determination of OMT and MT and in the pharmacokinetic studies of these compounds. The blood and dermal concentration-time profile of OMT and its metabolite MT suggest that the limiting factor for dermal metabolism is the low capacity of enzymes in the skin rather than the quantity of penetrated OMT.

Several species of lupine (Lupinus spp.) are toxic to livestock, causing death losses in sheep and cattle but more commonly crooked calf disease in pregnant range cows. The major toxic alkaloids in lupine are of the quinolizidine alkaloid group and include the teratogen anagyrine, which is primarily responsible for crooked calf disease. Lupines also contain teratogenic piperidine alkaloids including ammodendrine. Previous work in sheep has shown that lupine alkaloid clearance may be influenced by the animal's physiological status. Therefore, the purpose of this study was to determine if differences in body condition of cattle would alter the absorption and elimination of anagyrine or ammodendrine given in a single oral dose as Lupinus leucophyllus or Lupinus sulphureus, respectively. Mature non-lactating cows in low body condition (LBC, n = 4) and high body condition (HBC, n = 4) received a single dose of dry ground lupine plant (2.0 g/kg of BW) via oral gavage. Lupinus leucophyllus (anagyrine) was dosed first; then after 21 d the same animals were dosed with L. sulphureus (ammodendrine). Blood samples were taken via jugular venipuncture 0 to 60 h after dosing. Serum anagyrine and ammodendrine concentrations were evaluated. The concentration of anagyrine was greater (P = 0.001) in the HBC group and peaked 2 h after dosing versus 12 h in LBC cows. Similarly for ammodendrine, the alkaloid concentration peaked at 3 h after dosing for the HBC group compared with 6 h for the LBC group (P = 0.001). Area under the curve tended to differ (P

A rapid, sensitive and selective high-performance liquid chromatography tandem mass spectrometric method (HPLC-MS) has been developed and validated for the simultaneous determination of matrine (MT), oxymatrine (OMT) and oxysophocarpine (OSP) in rat plasma after oral administration of Sophora flavescens Ait. extract using pseudoephedrine hydrochloride as an internal standard (I.S.). The three analytes were extracted from the plasma samples by liquid-liquid extraction with chloroform. The chromatographic separation was accomplished on a Kromasil C18 column (150 mm x 4.6 mm). Detection was performed on a single quadrupole mass spectrometer by selected ion monitoring (SIM) mode via electrospray ionization (ESI) source. The total run time was 12 min between injections. The assay had a lower limit of quantification of 1.0 ng/ml for MT, 2.0 ng/ml for OMT and 2.0 ng/ml for OSP using 200 microl of plasma. The calibration curves were linear in the measured range. The overall precision and accuracy for all concentrations of quality controls and standards was better than 15%. The proposed method enables unambiguous identification and quantification of MT, OMT and OSP in vivo. This was the first report on determination of the major quinolizidine alkaloids in rat plasma after oral administration of Sophora flavescens Ait. extract. The results provided a meaningful basis for evaluating the clinical applications of the herbal medicine.

To establish an HPLC-MS method for simultaneous determination of matrine, oxymatrine and oxysophocarpine in rat plasma after oral administration of herbal preparation, namely Sanwu Huangqin decoction, and the pharmacokinetic porameters were calculated as well. Matrine, oxymatrine, oxysophocarpine, and internal standard pseudoephedrine were extracted from plasma with liquid-liquid extraction, then separated on a Kromasil C18 column by using acetonitrile-0.1% aqueous formic acid (10 : 90) as mobile phase. Electrospray ionization (ESI) source was applied and operated in positive ion mode. The linear calibration curve was obtained in the concentration range of 10 -5 000 ng x mL(-1) for matrine, 2 - 1 000 ng x mL(-1) for oxymatrine, and 2 - 1 000 ng x mL(-1) for oxysophocarpine. The extraction recovery was 89.1% - 93.5%, 83.9% - 91.3%, and 85.4% - 88.0% accordingly. The inter- and intra- day precision (RSD) was below 15.0% calculated from quality control (QC) samples. Matrine, oxymatrine and oxysophocarpine concentration time profile conformed to a two-compartment pharmacokinetic model. The method was shown to be effective, convenient, and suitable for simultaneous pharmacokinetic study of matrine, oxymatrine, and oxysophocarpine in rat.

A sensitive and selective liquid chromatographic-mass spectrometric method is built to determine oxymatrine in human plasma. After a liquid-liquid extraction for samples, samples are analyzed on a C18 column interfaced with a mass spectrometer. Positive electrospray ionization is employed as the ionization source. The mobile phase is methanol-water containing 10 mmol/L ammonium acetate (60:40) at the flow rate of 0.8 mL/min. The method is linear in the concentration range of 10-1000 ng/mL. The lower limit of quantitation is 10 ng/mL. The intra- and inter-day relative standard deviation across three validation runs over the entire concentration range is less than 14.27%. The accuracy determined at three concentrations (20, 100, and 500 ng/mL for oxymatrine) is within +/- 10.0% in terms of relative error. The method herein described is successfully applied to the evaluation of pharmacokinetic profiles of oxymatrine tablets pills in 18 healthy volunteers. The results show AUC, Tmax, Cmax, and T1/2 between the testing formulation and reference formulation have no significant difference (P > 0.05). Relative bioavailability is 104.2 +/- 13.8%.

A rapid, specific and sensitive LC-MS/MS method was developed for the determination of oxymatrine (OMT) and matrine (MT) in beagle dog plasma. The method was applied to study the pharmacokinetics of OMT and MT after oral administration of OMT, MT and Kushen formula granule (KFG) containing equivalent amounts of OMT and MT in a three-period crossover design. The analysis was carried out on an Acquity UPLC BEH C(18) column by linear gradient elution with 0.01% acetic acid-water-methanol as mobile phase. Detection was by positive ion electrospray ionization (ESI) mass spectrometry with multiple-reaction monitoring (MRM). Linear calibration curves were both obtained over the concentration range 15-2000 ng/mL, with a limit of quantification of 15 ng/mL. The matrix effect was minimized. The intra- and inter-day precisions (RSDs) were less than 12.4 and 14.7%, respectively, and the accuracy (RE) was from -2.1 to 2.7%. The validated method was used to determine the concentration-time profiles of OMT and MT. The results indicated that the absorption of OMT and MT after oral administration of KFG was significantly greater than that after oral administration of pure components., (Copyright (c) 2007 John Wiley & Sons, Ltd.)

A quantitative method of capillary electrophoresis with sample stacking induced by moving reaction boundary (MRB) was developed for sensitive determination of oxymatrine (OMT) and matrine (MT) in rat plasma. The experimental conditions were optimized firstly. Below are the optimized experimental conditions: 20 mM sodium formate solution (HCOONa, adjusted to pH 10.70 by ammonia) as sample solution, 3 min 14 mbar sample injection, 40 mM formic buffer (HCOOH-HCOONa, pH 2.60) as stacking buffer, 7 min 14 mbar injection of stacking buffer, 100 mM HCOOH-HCOONa (pH 4.80) as separation buffer, 73 cm capillary (effective length 64 cm), 21 kV voltage, 210 nm wavelength. Under the optimized conditions, higher than 60-fold sensitivity improvement of the stacking was simply achieved as compared with capillary zone electrophoresis, and the detectable limits obtained for OMT and MT were 0.26 and 0.19 microg mL(-1), respectively. Then, numerous demonstrations were carefully performed for the methodological validations of OMT and MT in rate plasma, including high specificity of method, good linearity (r=0.9993 for OMT, r=0.9991 for MT), fair wide linear concentration range (1.30-65.00 microg mL(-1) for OMT, 0.84-42.00 microg mL(-1) for MT), low limit of detection (1.03 microg mL(-1) for OMT, 0.38 microg mL(-1) for MT), less than 5% intra- and inter-day variance value, and higher than 96% recovery of OMT and MT in plasma. The developed method could be used for the trace analyses of OMT and MT in plasma and was finally used for the investigation on pharmacokinetic study of OMT in rat plasma.

Anti-DHBV (duck hepatitis B virus) activity was found in the aqueous extracts of Sophora flavescens Ait. in vivo. Liquid chromatography/electrospray ionization ion trap mass spectrometry was applied to characterize the components in duck serum after oral administration of S. flavescens extract. Oxymatrine (1), sophoranol (2), sophoridine (3) and matrine (4) were identified in the serum. Further research on the four compounds was evaluated for their antiviral activity against HBV (hepatitis B virus) in cell culture. The results suggested that oxymatrine, sophoranol and matrine were the efficacy substances for anti-HBV activity in aqueous extracts of S. flavescens Ait., (Copyright 2007 John Wiley & Sons, Ltd.)

A simple, rapid, and sensitive high-performance liquid chromatographic method is developed for the determination of ibafloxacin in rabbit plasma. Plasma proteins are precipitated with acetonitrile, and after extraction with methylene chloride followed by desecation, ibafloxacin is determined by reversed-phase chromatography with fluorescence detection exciting at 330 nm and emission at 368 nm. Peaks corresponding to ibafloxacin and the internal standard (salycilic acid) are obtained at 9.8 and 5.2 min, respectively. The method is validated for a limit of quantitation of 10 ng/mL. The intraday relative standard deviation ranges from 4.78-7.15%, and the interday precision ranges from 1.32-4.03%. The method shows linearity for the two calibration curves used (10-100 ng/mL and 100-2000 ng/mL). The procedure described is applied successfully to a pharmacokinetics study of ibafloxacin in rabbits.

A high-performance liquid chromatography (HPLC) method for determining sophoridine in rat plasma was developed for application in the pharmacokinetic studies. The plasma was deproteinized with acetonitrile that contained an internal standard (ephedrine) and was separated from the aqueous layer by adding sodium chloride and sodium carbonate. The HPLC assay was carried out using a YMC-ODS column. The mobile phase was methanol-ethanol-0.01 moll(-1) ammonium acetate buffer-triethylamine (10:0.5:89.5:0.03, v/v/v/v) (pH 6.80). The flow rate was 0.8 ml min(-1). The detection wavelength was set at 210 nm. The method was used to determine the concentration-time profiles of sophoridine in the plasma following oral administration or injection of sophoridine aqueous solution. The fractions of sophoridine reaching the systemic circulation were estimated for the first time by a deconvolution method.

There is little information about the pharmacokinetics of oxymatrine (OMT) and its metabolite matrine (MT) after i.v. administration of OMT in human. Therefore a specific and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method was established for the determination and pharmacokinetic study of OMT and its metabolite MT in human plasma after i.v. infusion administration of 600 mg of OMT in 100 ml of 5% glucose injection in 0.5 h. The analysis was carried out on a Lichrospher-CN column (250 mmx4.6 mm, i.d., 5 microm, Merck) with mobile phase of methanol-ammonium acetate (20 mmol/l; 85:15, v/v) pumped at a flow rate of 1.0 ml/min. The tandem mass detection was made with electrospray ionization in positive ion selected reaction monitoring mode, with argon collision-induced dissociation ion transitions m/z 265.2 to m/z 265.2 for OMT at 25 eV, m/z 249.2 to m/z 249.2 for MT at 25 eV and m/z 340.2 to m/z 324.0 at 35 eV for the internal standard (papaverine), respectively. The assay was validated to be accurate and precise for the analysis in the concentration range of 1.0-40,000 ng/ml for both OMT and MT with the LOD being 0.5 and 0.2 ng/ml, respectively, when 0.25 ml of human plasma sample was processed with papaverine as internal standard. The pharmacokinetic study was made with 10 healthy male Chinese subjects. The plasma concentration time profiles of OMT and MT obtained were best fitted with two-compartment and one-compartment models, respectively. The main pharmacokinetic parameters found for OMT and MT after i.v. infusion were as follows: Cmax (20,519+/-7581) and (247+/-45) ng/ml, Tmax (0.5+/-0.1) and (5.6+/-1.7) h, AUC0-t (20,360+/-5205) and (3817+/-610) ng h/ml, AUC0-infinity (20,436+/-5188) and (3841+/-615) ng h/ml, t1/2 (2.17+/-0.49) and (9.43+/-0.62) h, respectively. The CL/F and Vd/F of OMT were (43.8+/-10.8) l h-1 and (70.1+/-26.6) l, respectively. Therefore only a small amount of OMT was reduced to MT following i.v. administration of OMT judged by the AUCs.

A sensitive and specific method was developed for the determination of sophoridine (SRI), sophocarpine (SC) and matrine (MT) in rabbit plasma by HPLC-MS. After an administration of Kuhuang by injection, blood samples were collected and extracted with methanol. The extract solutions were analysed by HPLC-MS method. The separation was performed on a ZORBAX Extend-C18 column using methanol/water/diethylamine (50:50:0.07, v/v/v) as mobile phase. The quinolizidine alkaloids were detected by using mass spectrometry in the SIM mode. There was a good linear relationship between peak area and concentration of analytes over the concentration range of 13.2-995.0 ng mL(-1) for SRI, 7.0-530.0 ng mL(-1) for SC and 8.8-655.0 ng mL(-1) for MT, respectively. The absolute recovery of this method was more than 57% for SRI, 87% for SC and 91% for MT. The accuracy of assay was more than 90%. The limits of detection (LODs) were 6.8 ng mL(-1) for SRI, 3.5 ng mL(-1) for SC and 4.2 ng mL(-1) for MT, respectively. The limits of quantitation (LOQs) were 13.2 ng mL(-1) for SRI, 7.0 ng mL(-1) for SC and 8.8 ng mL(-1) for MT, respectively. The intra-day and inter-day coefficients of variation (RSDs) were less than 10.1, 6.3 and 5.8% for SRI, SC and MT, respectively. The developed method was applied to determine the concentration-time profiles of SRI, SC and MT in rabbit plasma after injection of Kuhuang.

The pharmacokinetics of ibafloxacin following single and repeated administration of an oral gel formulation and the effect of food intake were investigated in cats. Ibafloxacin is a chiral fluoroquinolone available for clinical use as a racemic mixture of the R- and S-enantiomers. Plasma concentrations of ibafloxacin and its metabolites were determined using microbiological, LC-MS-MS and enantioselective capillary zone electrophoresis assays. Ibafloxacin was absorbed rapidly [time of maximum concentration (tmax) 2-3 h], reaching a mean maximum concentration (Cmax) of approximately 2.1 and 1.6 microg/mL for R- and S-ibafloxacin, respectively, following a single oral administration of the racemate at 15 mg/kg. Once absorbed, ibafloxacin was metabolized to 7-hydroxy-ibafloxacin and mainly to 8-hydroxy-ibafloxacin. Following repeated oral administration, significant increases in Cmax and AUC of ibafloxacin and its less active metabolites (racemic or enantiomers) were observed between the first and the tenth day of treatment. This twofold exposure increase in concentrations of ibafloxacin and its metabolites may contribute additionally to the efficacy of this drug in the treatment of feline bacterial infections. Single and repeated doses of ibafloxacin were well tolerated by cats. Food promoted the absorption of ibafloxacin, doubling Cmax and increasing AUC and slightly delaying tmax. High concentrations of the metabolites, mainly 8-hydroxy- and 7-hydroxy-ibafloxacin were excreted in urine, either unchanged or as glucurono-conjugates.

Objective: To compare plasma disposition of alkaloids after lupine challenge in cattle that had given birth to calves with lupine-induced arthrogryposis and cattle that had given birth to clinically normal calves and determine whether the difference in outcome was associated with differences in plasma disposition of anagyrine., Animals: 6 cows that had given birth to calves with arthrogryposis and 6 cows that had given birth to clinically normal calves after being similarly exposed to lupine during pregnancy., Procedures: Dried lupine (2 g/kg) was administered via gavage. Blood samples were collected before and at various time points for 48 hours after lupine administration. Anagyrine, 5,6-dehydrolupanine, and lupanine concentrations in plasma were measured by use of gas chromatography. Plasma alkaloid concentration versus time curves were generated for each alkaloid, and pharmacokinetic parameters were determined for each cow., Results: No significant differences in area under the plasma concentration versus time curve, maximum plasma concentration, time to reach maximum plasma concentration, and mean residence time for the 3 alkaloids were found between groups., Conclusions and Clinical Relevance: Because no differences were found in plasma disposition of anagyrine following lupine challenge between cattle that had given birth to calves with arthrogryposis and those that had not, our findings do not support the hypothesis that between-cow differences in plasma disposition of anagyrine account for within-herd differences in risk for lupine-induced arthrogryposis.

Several species of lupine (Lupinus spp.) are poisonous to livestock, producing death in sheep and "crooked calf disease" in cattle. Range livestock cope with poisonous plants through learned foraging strategies or mechanisms affecting toxicant disposition. When a toxic plant is eaten, toxicant clearance may be influenced by the animal's nutritional and/or physiological status. This research was conducted to determine whether differences in body condition or short-term nutritional supplementation of sheep altered the disposition of lupine alkaloids given as a single oral dose of ground silvery lupine (Lupinus argenteus) seed. Ewes in average body condition (ABC, n = 9) and low body condition (LBC, n = 10) received a single dose of ground lupine seeds including pods (8.5 g/kg BW) via gavage on the first day of the experiment, and were then randomly assigned to one of two nutritional supplement treatments. Blood samples were taken 0 to 60 h after dosing to compare blood alkaloid concentration and to evaluate alkaloid absorption and elimination profiles. Concentrations of total alkaloid and anagyrine, 5,6 dehydrolupanine, lupanine, and alkaloid E were measured in serum. These four alkaloids constituted 78 and 75% of the total alkaloid concentration in serum for LBC vs. ABC groups, respectively. Initial analysis indicated that short-term supplementation had no effect on alkaloid disposition, and supplementation was removed from the statistical model. The highest concentration of total alkaloids was observed 2 h after dosing. Overall, serum total alkaloid and anagyrine levels (area under the curve) were higher (P < 0.01) for sheep in the LBC group. Serum peak concentrations of total alkaloid and anagyrine were higher in LBC vs. ABC groups (P < 0.05). Serum elimination of anagyrine, unknown alkaloid E, and lupanine was decreased in LBC vs. ABC treatments (P < 0.05). These results demonstrate that body condition is important in the disposition of lupine alkaloids; however, further research is needed to determine the potential benefit, if any, that short-term nutritional supplementation might have on alkaloid disposition.

Quinolones are a group of synthetic antibiotics that are widely used in veterinary medicine. Their residues may remain in tissues, milk, etc. intended for human consumption. The European Union fixes the maximum residue limits (MRLs) of veterinary medicinal products in foodstuffs of animal origin. Analytical methods are therefore needed to determine them in biological samples. In this study, we describe capillary isotachophoresis-capillary zone electrophoresis (ITP-CZE) to analyze three quinolones, enrofloxacin (ENR), ciprofloxacin (CPR) and flumequine (FLU), in pig plasma samples. We used solid-phase extraction with Oasis HLB cartridges as a sample pretreatment clean-up step. Capillary zone electrophoresis (CZE) requires low amounts of sample and is not as sensitive as one would wish. ITP-CZE is an easy way to increase the sample loadability and sensitivity. With this system sensitivity increases 40-fold. The detection limits for CPR, ENR and FLU were 70, 85 and 50 microg l(-1), respectively, which were lower than their MRLs in different kinds of samples. This method is simple and sensitive, and is therefore an alternative tool to the existing HPLC methods for analyzing the residuals of these quinolones in biological samples.

The objectives of this double-blind, placebo-controlled study were to assess the multiple-dose tolerability, pharmacodynamics, and pharmacokinetics of the hypnotic agent Ro 41-3696 in elderly men and women (55-75 y of age). On day 1 and days 3-8, doses of 1, 3, 5, and 10 mg were administered sequentially to 4 groups of 10 subjects, 2 of whom received placebo. Psychomotor performance tests (tracking and attention) were conducted just before and at 1.5, 4, and 8 hours after drug intake on days 1, 4, 6, and 8. Memory was assessed at 24 hours after drug intake on days 1 and 8 by recall of a list of 10 words, which had been learned at 2 hours after intake. Ro 41-3696 was well tolerated at all dose levels. One subject dropped out of the study because of a hypersensitive skin reaction during treatment with 10 mg. Performance in both a tracking test and a memory search test was significantly affected by a dose of 10 mg and moderately affected by doses of 3 and 5 mg. The results of the 1-mg dose were indistinguishable from those of placebo. Long-term memory, as assessed by a word learning and recall test, showed the same pattern. Partial tolerance to the impairing effects in the psychometric tests developed over the course of treatment. Pharmacokinetics of both Ro 41-3696 and its O-desethyl metabolite Ro 41-3290 were dose proportional and time independent. Ro 41-3696 was absorbed and eliminated rapidly (time of maximum plasma concentration, approximately 1 hour; elimination half-life, approximately 2 hours). Plasma levels of Ro 41-3290 were higher than those of the parent drug, and it was more slowly eliminated (values for time of maximum plasma concentration and elimination half-life, approximately 2 and approximately 7 hours, respectively).

Knowledge of the pharmacokinetic properties of drugs to combat bacterial infections in the European eel (Anguilla anguilla) is limited. One antimicrobial agent likely to be effective is flumequine. The aim of this study was to investigate the pharmacokinetic properties of flumequine in European eels in fresh water. Flumequine was administered to eels (Anguilla anguilla) intravenously (i.v.) and orally (p.o.) at a dose of 10 mg/kg body weight, and as a bath treatment at a dose of 10 mg/L water for 2 h. The study was performed in fresh water with a temperature of 23 + 0.3 degrees C, pH 7.15. Identical experimental designs were used. Two additional bath treatments were also performed, one in which the pH in the water was lowered by approximately 1 unit to 6.07 (dose: 10 mg/L) and one at a dose of 40 mg/L for 2 h in a full-scale treatment. Following i.v. administration, the volume of distribution at steady state was 3.4 L/kg. Total body clearance was 0.012 L/h per kg and the elimination half-life (t1/2lambda z) was calculated to be 314 h. Mean residence time was 283 h. Following oral administration, the t1/2lambda z was 208 h. Maximal plasma concentration (Cmax) was 9.3 mg/L, at 7 h after administration (Cmax). The oral bioavailability (F) was calculated to be 85%. Following bath administration in 10 mg/L for 2 h, maximal plasma concentration was 2.1 mg/L, observed immediately after the end of the bath. The 'bioavailability' in eel following a 2-h bath treatment was 19.8%. Reducing the pH in the bath to 6.07 produced a maximal plasma concentration of 5.5 mg/L, observed immediately after the end of the bath. The 'bioavailability' was increased to 41% by the lowering of the pH. A similar effect was observed in a full-scale treatment (1 kg eels/L water). The CO2 produced by the eel lowered the pH and increased 'bioavailability' to 35%.

Knowledge of the pharmacokinetic properties of drugs to combat bacterial infections in cod (Gadus morhua) and wrasse (Ctenolabrus rupestris) is limited. One antimicrobial agent likely to be effective is flumequine. The aim of this study was to investigate the pharmacokinetic properties of flumequine in these two species. Flumequine was administered intravenously to cod (G. morhua) at a dose of 5 mg/kg bodyweight and wrasse (C. rupestris) at a dose of 10 mg/kg. Flumequine was also administered orally to both species at a dose of 10 mg/kg body weight, and as a bath treatment at a dose of 10 mg/L water for 2 h. Identical experimental designs were used otherwise. The study was performed in seawater with a salinity of 3.2% and a temperature of 8.0 +/- 0.2 degrees C (cod) and 14.5 +/- 0.4 degrees C (wrasse). Pharmacokinetic modelling of the data showed that flumequine had quite different pharmacokinetic properties in cod and wrasse. Following intravenous administration, the volumes of distribution at steady-state (Vss) were 2.41 L/kg (cod) and 2.15 L/kg (wrasse). Total body clearances (Cl) were 0.024 L/hxkg (cod) and 0.14 L/hxkg (wrasse) and the elimination half-lives (t1/2lambda z) were calculated to be 75 h (cod) and 31 h (wrasse). Mean residence times (MRT) were 99 h (cod) and 16 h (wrasse). Following oral administration, the t1/2 lambda z were 74 h (cod) and 41 h (wrasse). Maximal plasma concentrations (tmax) were 3.5 mg/L (cod) and 1.7 mg/L (wrasse), and were observed 24 h post-administration in cod and 1 h post-administration in wrasse. The oral bioavailabilities (F) were calculated to be 65% (cod) and 41% (wrasse). Following bath administration, maximal plasma concentrations were 0.13 mg/L (cod) and 0.09 mg/L (wrasse), and were observed immediately after the end of the bath.

The study demonstrates that the oral extent of bioavailability of flumequine in the rat, relative to the intravenous injection, is complete (0.94 +/- 0.04) and not significantly different from that found by the intraduodenal route (0.95 +/- 0.04). The rate of oral bioavailability, however, is slow (ka = 1.20 +/- 0.07 h-1; Tmax = 2.0 h), but enough to maintain plasma levels above the minimal inhibitory concentration of the most common pathogens for an extended period of time (about 10 h). The reason for the oral absorption slowness could be a slow gastric emptying, an adsorption to the gastric mucosae, a precipitation in the gastric medium or any other feature concerning the stomach as the intraduodenal administration is very quick (kid = 38.1 +/- 4.7 h-1; Tmax = 0.05 h). A possible precipitation of flumequine cannot be discarded as the solubility of flumequine is very low in the pH range of 3 to 6 (mean pH values for rat stomach and rat intestine, respectively; T.T. Kararli, Biopharm. Drug Dispos. 16 (1995) 351-380). Flumequine was shown to be not substantially excreted in bile (2-3% of the dose). Surprisingly, plasma levels and AUC values found for animals with interrupted bile flow always surpass those found for animals with enterohepatic circulation. This could be due to experimental model features, which might bias plasmatic flumequine concentrations if the homeostatic equilibrium of the animal is not completely restored due to the volume reduction induced by biliary extraction.

Rapid methods are described for determination of flumequine (FLU) residues in muscle and plasma of farm-raised channel catfish (Ictalurus punctatus). FLU residues were extracted from tissues with an acidified methanol solution, and extracts were cleaned up on C18 solid-phase extraction cartridges. FLU concentrations were determined by liquid chromatography (LC) using a C18 analytical column and fluorescence detection (excitation, 325 nm; emission, 360 nm). Mean recoveries of FLU from fortified muscle were 87-94% at 5 levels ranging from 10 to 160 ppb (5 replicates per level). FLU recoveries from fortified plasma were 92-97% at 5 levels ranging from 20 to 320 ppb. Limits of detection (signal-to-noise ratio, 3:1) for the method as described were 3 and 6 ppb for muscle and plasma, respectively. Relative standard deviations (RSDs) for recoveries were < or = 12%. Live catfish were dosed with 14C-labeled or unlabeled FLU to generate incurred residues. Recoveries of 14C residues throughout extraction and cleanup were 90 and 94% for muscle and plasma, respectively. RSDs for incurred FLU at 2 levels in muscle and plasma ranged from 2 to 6%. The identity of FLU in incurred tissues was confirmed by LC/mass spectrometry.

Dolasetron mesylate (MDL 73,147, Anzemet, Hoechst Marion Roussel, Kansas City, MO) is a 5-HT ( 3 ) receptor antagonist undergoing clinical evaluation as an antiemetic agent. Dolasetron is rapidly metabolized to form hydrodolasetron (MDL 74,156). The pharmacokinetics of hydrodolasetron were studied after administration of a single intravenous infusion of 0.6 mg/kg (group I) or 1.8 mg/kg (group II) in 21 cancer patients participating in a randomized, double-blind, parallel-group, multicenter trial of the drug in patients receiving their first course of high-dose (>/=75 mg/m ( 2 ) ) cisplatin-containing chemotherapy. The intent of this study was to obtain preliminary data on the pharmacokinetics of the active metabolite, hydrodolasetron, in cancer patients. The reduced metabolite, hydrodolasetron, was formed rapidly with peak plasma concentrations (group I, mean = 128.6 ng/mL; group II, mean = 505.3 ng/mL) occurring at or shortly after the end of the infusion. Plasma concentrations of hydrodolasetron remained quantifiable for up to 24 hours. Increases in peak plasma concentrations and AUC of hydrodolasetron were proportional to dose, suggesting linear pharmacokinetics over this dose range. Apparent clearance, apparent volume of distribution, elimination rate, and terminal elimination half-life of the reduced metabolite were similar at both doses. The results support a pharmacokinetic basis for the prolonged duration of antiemetic efficacy after a single intravenous dose.