RESUMEN

In this article, a tensegrity-based knee mechanism is studied for developing a high-efficiency rehabilitation knee exoskeleton. Moreover, the kinematics and dynamics models of the knee mechanism are explored for bringing about further improvement in controller design. In addition, to estimate the performance of the bionic knee joint, based on the limit function of knee patella, the limit position functionality of the bionic knee joint is developed for enhancing the bionic property. Furthermore, to eliminate the noise item and other disturbances that are constantly generated in the rehabilitation process, a noise-tolerant zeroing neural network (NTZNN) algorithm is utilized to establish the controller. This indicates that the controller shows an anti-noise performance; hence, it is quite unique from other bionic knee mechanism controllers. Eventually, the anti-noise performance and the calculation of the precision of the NTZNN controller are verified through several simulation and contrast results.

RESUMEN

BACKGROUND: Chronic obstructive pulmonary disease (COPD) not only causes respiratory damage, but also affects circulatory function, which can be life-threatening in severe cases. Therefore, it is very essential to reveal the molecular mechanism of its pathogenesis. METHODS: Human Bronchial Epithelial cells were exposed to 20% cigarette smoke extract (CSE) condition to simulate the cells in COPD patients. GEO database was applied to analyze the expression of miR-380 in COPD patients. The expression level of miR-380 in CSE model was determined with qRT-PCR. Cells proliferation, apoptosis, and inflammation response-related factors were detected with cell counting kit 8, flow cytometry, and Western blot, respectively. A correlation between miR-380 and Cholinergic Receptor Nicotinic Alpha 4 subunit (CHRNA4) was predicted with bioinformatics software, and confirmed by dual luciferase assay. Rescue assay was applied to explore further relationship between miR-380 and CHRNA4. RESULTS: miR-380 showed a tendency of high expression in COPD patients and CSE models. Overexpression of miR-380 promoted the inhibitory effect of cells proliferation, and promotion effects of cells apoptosis and inflammation response, which were caused by CSE. CHRNA4, which was lower expressed in COPD patients, was affirmed as a target of miR-380 and negatively modulated by miR-380. Rescue assay indicated that exhausting of CHRNA4 attenuated the moderating effects of miR-380 inhibitor on cells damage induced by CSE. CONCLUSIONS: Depletion of miR-380 alleviated cells damage caused by CSE through targeting CHRNA4, suggesting that miR-380/CHRNA4 may serve as novel therapeutic targets for COPD treatment.

Asunto(s)

Bronquios/patología , Células Epiteliales/metabolismo , MicroARNs/metabolismo , Enfermedad Pulmonar Obstructiva Crónica/genética , Receptores Nicotínicos/metabolismo , Secuencia de Bases , Fumar Cigarrillos , Regulación hacia Abajo/genética , Células Epiteliales/patología , Técnicas de Silenciamiento del Gen , Humanos , MicroARNs/genética , Enfermedad Pulmonar Obstructiva Crónica/patología , Receptores Nicotínicos/genética

RESUMEN

A rapid, accurate and specific high-performance liquid chromatography-tandem mass spectrometry method has been validated for the simultaneous determination of cefoperazone and sulbactam in a small volume sample for children. A Shim-pack XR-ODS C18 column with gradient elution of water (0.1% formic acid) and acetonitrile (0.1% formic acid) solution was used for separation at a flow rate of 0.3 mL/min. The calibration curves of two analytes in serum showed excellent linearity over the concentration ranges of 0.03-10 µg/mL for cefoperazone, and 0.01-3 µg/mL for sulbactam, respectively. This method involves simple sample preparation steps and was validated according to standard US Food and Drug Administration and European Medicines Agency guidelines in terms of selectivity, linearity, detection limits, matrix effects, accuracy, precision, recovery and stability. This assay can be easily implemented in clinical practice to determine concentrations of cefoperazone and sulbactam in children.

Asunto(s)

Cefoperazona/sangre , Cromatografía Líquida de Alta Presión/métodos , Monitoreo de Drogas/métodos , Sulbactam/sangre , Espectrometría de Masas en Tándem/métodos , Cefoperazona/química , Cefoperazona/farmacocinética , Niño , Preescolar , Estabilidad de Medicamentos , Humanos , Límite de Detección , Modelos Lineales , Reproducibilidad de los Resultados , Sulbactam/química , Sulbactam/farmacocinética

RESUMEN

A simple and sensitive HPLC-MS/MS method was developed and fully validated for simultaneous determination of ginsenoside Rb1, ginsenoside Rg1, paeoniflorin, albiflorin and oxypaeoniflorin in rat plasma. Plasma samples were pretreated with protein precipitation using acetonitrile. The chromatographic separation was carried out on a C18 column with a gradient mobile phase consisting of acetonitrile and water (containing 0.1% formic acid). All analytes and digoxin (internal stand, IS) were quantitated through electrospray ionization in negative ion multiple reaction monitoring mode. All calibration curves exhibited good linearity (r > 0.9960) over a wide concentration range for all components. The intra-day and inter-day precisions (RSD) at three different levels were all <12.0% and the accuracies (RE) ranging from -6.1 to 6.2%. The extraction recoveries of the five compounds ranged from 89.2 to 97.1%. The validated method was successfully applied in a comparative pharmacokinetic study of Wen-Yang-Huo-Xue soft capsule (WYHXSC) in rats. Compared with single pure component, the exposure of the investigated components, except for oxypaeoniflorin, increased after oral administration of WYHXSC in rats, which suggested a synergistic effects between the herbs in the WYHXSC preparations.

Asunto(s)

Hidrocarburos Aromáticos con Puentes/sangre , Cromatografía Líquida de Alta Presión/métodos , Medicamentos Herbarios Chinos/análisis , Ginsenósidos/sangre , Glucósidos/sangre , Monoterpenos/sangre , Animales , Hidrocarburos Aromáticos con Puentes/química , Hidrocarburos Aromáticos con Puentes/farmacocinética , Medicamentos Herbarios Chinos/administración & dosificación , Medicamentos Herbarios Chinos/química , Medicamentos Herbarios Chinos/farmacocinética , Ginsenósidos/química , Ginsenósidos/farmacocinética , Glucósidos/química , Glucósidos/farmacocinética , Modelos Lineales , Masculino , Monoterpenos/química , Monoterpenos/farmacocinética , Ratas , Ratas Sprague-Dawley , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Espectrometría de Masas en Tándem/métodos

RESUMEN

AIM: This study examined whether gene polymorphisms (CYP3A4, ABCG2, SLCO1B1, NR1I2, PPARA and NFKB1) influenced the pharmacokinetics of lovastatin in Chinese healthy subjects. PATIENTS & METHOD: Plasma concentrations of lovastatin and lovastatin acid were quantified using LC/MS/MS. RESULTS: PPARA c.208+3819 G allele carriers had approximately twofold higher AUC0-∞ and Cmax of lovastatin than wild-type (PPARA c.208+3819 AA) subjects. After adjustment for the PPARA variants, subjects with the SLCO1B1 521TT genotype had approximately 50% lower AUC0-∞ of lovastatin acid than those with 521TC/CC genotypes, while the AUC0-∞ of lovastatin lactone in NFKB1-94 DD wild-type carriers was twofold higher than in mutant homozygotes carriers. CONCLUSION: Gene polymorphisms of PPARA, SLCO1B1 and NFKB1 affected the pharmacokinetics of lovastatin.

Asunto(s)

Pueblo Asiatico/genética , Inhibidores de Hidroximetilglutaril-CoA Reductasas/farmacocinética , Lovastatina/farmacocinética , Polimorfismo de Nucleótido Simple/genética , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/genética , Citocromo P-450 CYP3A/genética , Voluntarios Sanos , Humanos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/sangre , Transportador 1 de Anión Orgánico Específico del Hígado/genética , Lovastatina/sangre , Subunidad p50 de NF-kappa B/genética , Proteínas de Neoplasias/genética , PPAR alfa/genética , Receptor X de Pregnano , Receptores de Esteroides/genética

RESUMEN

The nuclear receptors (NR)-farnesoid X receptor (FXR, NR1H4) and pregnane X receptor (PXR, NR1I2)-have important effects on the expression of genes related to the pharmacokinetics (PKs) of rosuvastatin. This study was designed to investigate whether the genetic variants in drug disposition genes (SLCO1B1 and ABCG2) combined with their upstream regulators (NR1H4 and NR1I2) would affect the PKs of rosuvastatin in a Chinese population. Sixty-one healthy male volunteers were enrolled and the plasma concentrations of rosuvastatin were measured using the liquid chromatographic-tandem mass spectrometry/MS method. All subjects were analyzed and grouped according to the genotypes of NR1H4, NR1I2, SLCO1B1, and ABCG2. The exposure of rosuvastatin was higher in subjects carrying the SLCO1B1 521C or ABCG2 421A allele compared with noncarriers. No association was observed of single-nucleotide polymorphisms in NR1H4 or NR1I2 genes with the PKs of rosuvastatin. After adjusting for the 421C>A and 521T>C variants, the Cmax in subjects with NR1I2 63396TT wild type were about 2-fold of those of NR1I2 mutant type (63396CC and CT) (10.7 vs. 20.4 ng/mL, P = 0.023), whereas no significant differences were observed for other parameters. Polymorphisms investigated in the genes of NR1H4 and NR1I2 seemed to play no significant role in the disposition of rosuvastatin.

Asunto(s)

Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/genética , Pueblo Asiatico/genética , Transportador 1 de Anión Orgánico Específico del Hígado/genética , Proteínas de Neoplasias/genética , Receptores Citoplasmáticos y Nucleares/genética , Receptores de Esteroides/genética , Rosuvastatina Cálcica/farmacocinética , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/metabolismo , Adulto , Voluntarios Sanos , Humanos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/farmacocinética , Transportador 1 de Anión Orgánico Específico del Hígado/metabolismo , Masculino , Proteínas de Neoplasias/metabolismo , Polimorfismo de Nucleótido Simple/efectos de los fármacos , Polimorfismo de Nucleótido Simple/genética , Receptor X de Pregnano , Receptores Citoplasmáticos y Nucleares/metabolismo , Receptores de Esteroides/metabolismo , Adulto Joven

RESUMEN

PURPOSE: To investigate the impact of valproic acid (VPA) and genetic polymorphism of the major metabolizing enzyme (UGT1A4, UGT2B7) of lamotrigine (LTG) and VPA on LTG concentration in Chinese epileptic children. METHODS: Three single nucleotide polymorphisms (UGT1A4*3, UGT2B7 -161C > T and UGT2B7*2) were analyzed by polymerase chain reaction-restriction fragment length polymorphism or direct DNA sequencing. The concentrations of LTG and VPA were measured by high-performance liquid chromatography (HPLC) and fluorescence polarization immunoassay, respectively. The adjusted concentration of LTG was defined as the concentration-to-dose-ratio (CDRLTG). Data analysis was performed using IBM SPSS Statistics 21.0. RESULTS: A total of 56 patients treated with LTG as monotherapy and 158 patients treated with LTG plus VPA were included in this study. In the polytherapy group, LTG concentration showed a good linear relationship with gender, age, daily LTG dose, VPA concentration, and UGT1A4*3 polymorphism, but had no relationship with the polymorphism of UGT2B7 -161C > T or UGT2B7*2. Moreover, LTG concentration and CDRLTG for the UGT1A4*3 were higher compared to UGT1A4*1 (LTG: 7.24 ± 3.51 vs 5.26 ± 3.27 µg/mL, p = 0.001; CDRLTG: 2.75 ± 1.02 vs 2.14 ± 0.96 µg/mL per mg/kg, p < 0.001, respectively). In the monotherapy group, there was no statistical difference between UGT1A4*3 and UGT1A4*1 in LTG concentration or CDRLTG. The patients in the polytherapy group were divided into two subgroups according to VPA concentration (lower/higher: 10-50/50-125 µg/mL). CDRLTG values of the patients carrying the UGT1A4*3 genotype were higher compared to UGT1A4*1*1 (2.86 ± 1.03 vs 2.22 ± 0.94 µg/mL per mg/kg, p = 0.001) only when the VPA concentration was higher. CONCLUSIONS: UGT1A4*3 polymorphism had an effect on LTG concentration only with VPA co-administration, and the effect was remarkable when VPA concentration was higher.

Asunto(s)

Anticonvulsivantes/farmacología , Anticonvulsivantes/farmacocinética , Epilepsia/genética , Glucuronosiltransferasa/genética , Triazinas/farmacocinética , Ácido Valproico/farmacología , Adolescente , Anticonvulsivantes/sangre , Pueblo Asiatico/genética , Niño , Preescolar , Quimioterapia Combinada , Epilepsia/sangre , Epilepsia/tratamiento farmacológico , Femenino , Genotipo , Humanos , Lamotrigina , Masculino , Polimorfismo de Nucleótido Simple , Triazinas/sangre

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Escin, a natural mixture of triterpene saponins, is commonly utilized for the treatment of chronic venous insufficiency, hemorrhoids, inflammation and edema. Escin Ia is the chief active ingredient in escin and plays key role in mediating its pharmacological effects. Adequate pharmacokinetic data are essential for proper application of escin agent in clinical practice. However, pharmacokinetic properties of escin Ia are still poorly understood and this conflicts with the growing use of escin agent over the years. The goal of this study is to investigate the pharmacokinetic behavior of escin Ia in rats after low, medium and high-dose intravenous administration. MATERIALS AND METHODS: Wistar rats were divided into 3 groups (n=6 per group) and escin Ia was administered via the caudal vein at doses of 0.5, 1.0 and 2.0 mg/kg, respectively. Subsequently, the concentrations of escin Ia and its metabolite isoescin Ia, a positional isomer of escin Ia, in rats׳ plasma were measured by an established liquid chromatography tandem mass spectrometry (LC-MS/MS) method at various time points following the administration of the drug. Main pharmacokinetic parameters were calculated by non-compartmental analysis using the TopFit 2.0 software package (Thomae GmbH, Germany). RESULTS: After intravenous administration, the Cmax and AUC of escin Ia increased in a dose-proportional manner at the dose of 0.5 mg/kg and 1.0 mg/kg, while increased in a more than dose-proportional manner at the doses of 1.0 mg/kg and 2.0 mg/kg. The t1/2 was significantly longer with increased intravenous doses, while other parameters such as CL and Vd also exhibit disagreement among three doses. Taken together, our data showed dose-dependent pharmacokinetic profile of escin Ia in rats after intravenous administration at the doses of 0.5-2.0 mg/kg. After intravenous administration, escin Ia was rapidly and extensively converted to isoescin Ia. CONCLUSIONS: The results suggested dose-dependent pharmacokinetics of escin Ia at the doses of 0.5-2.0 mg/kg after intravenous administration. Escin Ia is isomerized to isoescin Ia rapidly and extensively regardless of the doses.

Asunto(s)

Escina/farmacocinética , Animales , Área Bajo la Curva , Cromatografía Liquida , Relación Dosis-Respuesta a Droga , Femenino , Semivida , Masculino , Tasa de Depuración Metabólica , Ratas , Ratas Wistar , Espectrometría de Masas en Tándem

RESUMEN

A rapid, sensitive and reliable high-performance liquid chromatography-mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous quantification of the five main bioactive components, calycosin, calycosin-7-O-ß-d-glucoside, formononetin, astragaloside IV and schisandrin in rat plasma after oral administration of Shenqi Wuwei chewable tablets. Plasma samples were extracted using solid-phase extraction separated on a CEC18 column and detected by MS with an electrospray ionization interface in multiple-reaction monitoring mode. Calibration curves offered linear ranges of two orders of magnitude with r > 0.995. The method had a lower limit of quantitation of 0.1, 0.02, 0.1, 1 and 0.1 ng/mL for calycosin, calycosin-7-O-ß-d-glucoside, formononetin, astragaloside IV and schisandrin, respectively. Intra- and inter-day precisions (relative standard deviation) for all analytes ranged from 0.97 to 7.63% and from 3.45 to 10.89%, respectively. This method was successfully applied to the pharmacokinetic study of the five compounds in rats after oral administration of Shenqi Wuwei chewable tablets.

Asunto(s)

Ciclooctanos/sangre , Medicamentos Herbarios Chinos/administración & dosificación , Glucósidos/sangre , Isoflavonas/sangre , Lignanos/sangre , Compuestos Policíclicos/sangre , Saponinas/sangre , Triterpenos/sangre , Administración Oral , Animales , Cromatografía Líquida de Alta Presión/métodos , Ciclooctanos/química , Ciclooctanos/farmacocinética , Estabilidad de Medicamentos , Glucósidos/química , Glucósidos/farmacocinética , Isoflavonas/química , Isoflavonas/farmacocinética , Lignanos/química , Lignanos/farmacocinética , Modelos Lineales , Masculino , Compuestos Policíclicos/química , Compuestos Policíclicos/farmacocinética , Ratas , Ratas Sprague-Dawley , Reproducibilidad de los Resultados , Saponinas/química , Saponinas/farmacocinética , Sensibilidad y Especificidad , Comprimidos , Espectrometría de Masas en Tándem/métodos , Triterpenos/química , Triterpenos/farmacocinética

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Adequate pharmacokinetic data of escin, a natural mixture of triterpene saponins used for the treatment of chronic venous insufficiency, hemorrhoids, inflammation and edema, is of special interest in view of the growing use of escin agent in clinical medicine. However, pharmacokinetic data are inadequate to support their clinical indication. Escin Ib and isoescin Ib are the chief active ingredients in escin, pharmacokinetics study of them would be helpful for improving the practice of escin application. The goals of this study are to determine the plasma concentration of escin Ib and isoescin Ib using an established liquid chromatography tandem mass spectrometry (LC-MS/MS) method and to compare the pharmacokinetics and bioavailability of these compounds in rats when administered as pure isomers or as sodium escinate. MATERIALS AND METHODS: Five groups of Wistar rats (n=6 per group) were treated with either an intravenous (IV) dose (2.78mg/kg) of sodium escinate (corresponding to 0.5mg/kg of escin Ib and 0.5mg/kg of isoescin Ib), an IV dose (0.5mg/kg) and an oral dose (4mg/kg) of pure escin Ib or isoescin Ib. The concentrations of escin Ib and isoescin Ib in rat plasma were determined by LC-MS/MS at various times following the administration of the drugs. The pharmacokinetic parameters were estimated by a non-compartmental analysis and then subjected to statistical analysis. RESULTS: The administration of sodium escinate, which contains the two isomers, gave rise to higher terminal phase half-life (t1/2) and mean residence time (MRT) values for both escin Ib and isoescin Ib compared to the corresponding compounds administered alone. The absorption of escin Ib and isoescin Ib was very poor, with the oral bioavailability (F) values of <2% observed for both compounds. The two compounds were found to isomerize in vivo, wherein the conversion of escin Ib to isoescin Ib was much easier than that of isoescin Ib to escin Ib. CONCLUSIONS: A comparison of the pharmacokinetics of escin Ib and isoescin Ib administered alone and together in rats suggests that the administration of herbal preparations of escin in a clinical setting may result in a longer duration of action than the administration of each isomer alone. The interconversion of escin Ib and isoescin Ib when administered alone indicates that the administration of one isomer results in exposure to the other isomer.

Asunto(s)

Escina/farmacocinética , Administración Intravenosa , Administración Oral , Animales , Escina/sangre , Femenino , Masculino , Ratas , Ratas Wistar

RESUMEN

PURPOSE: Codeine is an analgesic drug acting on µ-opioid receptors predominantly via its metabolite morphine formed almost exclusively by CYP2D6. Genetic polymorphisms in CYP2D6 are associated with diminished pain relief and/or severe opioid side effects. In Chinese individuals, CYP2D6*10 is the most common allele with reduced enzyme activity. In this study, we investigated the effect of this allele on the pharmacokinetics of codeine and its metabolites. METHOD: A blood sample was collected from healthy Mongolian volunteers for CYP2D6 genotyping using a PCR-RFLP assay. A pharmacokinetic study was then carried out in three groups with CYP2D6*1/*1 (n=10), CYP2D6*1/*10 (n=10) and CYP2D6*10/*10 (n=9) genotypes by collecting serial blood samples for determination of plasma levels of codeine and its metabolites, morphine, morphine 3-glucuronide (M3G) and morphine 6-glucuronide (M6G) before and after a single 30-mg oral dose of codeine phosphate. Codeine and its metabolites were measured by LC-MS/MS. RESULTS: No significant differences were observed in the pharmacokinetic parameters of codeine in the three genotype groups. However, the C( max) and AUC(0-∞) of morphine, M3G and M6G were significantly different between the study groups (P<0.05). Compared with the *1/*1 group, the AUC(0-∞) for morphine in the *1/*10 and *10/*10 groups decreased by ratios (95 % CI) of 0.93 (0.26-1.59) and 0.494 (0.135-0.853) respectively. Corresponding ratios for M3G were 0.791 (0.294-1.288) and 0.615 (0.412-0.818) and for M6G were 0.643 (0.39-0.957) and 0.423 (0.267-0.579). CONCLUSION: This study demonstrates that the CYP2D6*10 allele plays an important role in the pharmacokinetics of the O-demethylated metabolites of codeine after oral administration.

Asunto(s)

Analgésicos Opioides/farmacocinética , Codeína/farmacocinética , Citocromo P-450 CYP2D6/genética , Administración Oral , Adulto , Alelos , Analgésicos Opioides/sangre , Área Bajo la Curva , Pueblo Asiatico/genética , Codeína/sangre , Citocromo P-450 CYP2D6/metabolismo , Femenino , Genotipo , Humanos , Masculino , Mongolia , Morfina/sangre , Derivados de la Morfina/sangre , Polimorfismo Genético , Adulto Joven

RESUMEN

A rapid and sensitive bioassay based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed and validated for the simultaneous determination of codeine and its active metabolites, including morphine, morphine 3ß-glucuronide (M3G) and morphine 6ß-glucuronide (M6G), in human plasma. Sample preparation of plasma after the addition of naloxone as internal standard (IS) involved solid-phase extraction (SPE) on C18 cartridges. Reversed-phase chromatography using a gradient elution with methanol and 0.04% formic acid solution (pH 3.5) was used for separation in a run time of 5 min. The analytes were detected in the positive ion mode using multiple reaction monitoring (MRM) of the transitions at m/z 300.4→215.2 for codeine, 286.2→152.0 for morphine, and 462.2→286.2 for M3G and M6G. The method has the following performance characteristics: a reliable response range of 0.05-80 ng/ml for codeine, M3G and M6G and a response range of 0.05-5.0 ng/ml for morphine with correlation coefficients (r) of >0.997 for all analytes. The lower limit of quantitation (LLOQ) for all four analytes was 0.05 ng/ml. The intra- and inter-day precision and accuracy of the quality control samples at low, medium and high concentration levels showed <12% relative standard deviation (RSD) and -6.9 to 8.1% relative error (RE) for all the analytes. The method was successfully applied to a pharmacokinetic study of codeine in healthy Mongolian Chinese volunteers after a 30 mg oral dose.

Asunto(s)

Cromatografía Liquida/métodos , Codeína/sangre , Espectrometría de Masas en Tándem/métodos , Administración Oral , Adulto , Codeína/administración & dosificación , Codeína/farmacocinética , Humanos , Reproducibilidad de los Resultados , Adulto Joven

RESUMEN

PURPOSE: To determine the allele frequency of three codon-changing variants (CYP2C8*2, CYP2C8*3, and CYP2C8*4) in the Han, Uighur, Hui, and Mongolian Chinese populations, and compare genetic polymorphism differences between the Han and minority Chinese ethnicities. METHODS: Five hundred seventy four healthy unrelated volunteers from four major nationalities (Han: 136; Uighur: 153; Hui: 158; Mongolian: 127) in China were recruited. The study was approved by the local research ethics committee. DNA was extracted from peripheral leukocytes using a standard protocol. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was developed to detect three alleles of CYP2C8. PCR results were confirmed by subsequent direct DNA sequencing. RESULTS: The three minorities showed the CYP2C8 polymorphism with an allele frequency as follows: the allele frequencies of CYP2C8*2, CYP2C8*3, and CYP2C8*4 were 0.33%, 2.94%, and 2.29% in Uighur; 0.39%, 1.57%, and 1.18% in Mongolian, and 0%, 1.58%, and 0.63% in Hui, respectively. For Han, CYP2C8*2, CYP2C8*3, and CYP2C8*4 were absent. CONCLUSION: To the best of our knowledge, the current study described polymorphisms of CYP2C8 in Chinese minorities for the first time. The results showed that there were significant ethnic differences in the distribution of CYP2C8 in the Han and three minorities, that is, the Uighur, Hui, and Mongolian Chinese populations.

Asunto(s)

Hidrocarburo de Aril Hidroxilasas/genética , Pueblo Asiatico/etnología , Frecuencia de los Genes , Polimorfismo Genético , Adulto , Alelos , Pueblo Asiatico/genética , China/etnología , Citocromo P-450 CYP2C8 , Genotipo , Humanos , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Análisis de Secuencia de ADN , Adulto Joven

RESUMEN

OBJECTIVE: Using the stable isotopes as the internal standard of microdialysis technology to establish a new method to study the whole and local brain dynamics of nicotine percutaneous preparations. METHOD: Using th healthy rats as experimental animals, administrating nicotine in abdominal transdermal way, then sample in the blood and brain simultaneously by microdialysis which use deuterium nicotine (DL-nicotine) as internal standard. Detecting the samples by LC-MS/MS method. RESULT: The configuration process in blood and brain both conforms to 2 compartments model, t1/2 is 29.38 min, t1/2beta is 208.51 min, AUC(0-infinity) is 152 127.10 microg x min x L(-1) in the blood t1/2 is 86.64 min, t1/2beta is 386.00 min, AUC(0-infinity) is 152 820.90 microg x min x L(-1) in the brain. CONCLUSION: Dl-nicotine can be used as internal standard of nicotine to correcte the recovery; Stable isotopes internal standard microdialysis technology can be used for studing the whole and the local pharmacokinetic of nicotine and also provide new ideas and methods to studing the process of new drug delivery system.

Asunto(s)

Química Encefálica , Encéfalo/metabolismo , Marcaje Isotópico/métodos , Microdiálisis/métodos , Nicotina/farmacocinética , Animales , Deuterio/química , Masculino , Nicotina/sangre , Ratas , Ratas Sprague-Dawley

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Escin Ia and isoescin Ia have been traditionally used clinically as the chief active ingredients of escin, a major triterpene saponin isolated from horse chestnut (Aesculus hippocastanum) seeds for the treatment of chronic venous insufficiency, hemorrhoids, inflammation and edema. AIM OF THE STUDY: To establish a sensitive LC-MS/MS method and investigate the pharmacokinetic properties of escin Ia and isoescin Ia in rats and the pharmacokinetics difference of sodium escinate with pure escin Ia and isoescin Ia. The absolute bioavailability of escin Ia and isoescin Ia and the bidirectional interconversion of them in vivo were also scarcely reported. MATERIALS AND METHODS: Wister rats were administrated an intravenous (i.v.) dose (1.7 mg/kg) of sodium escinate (corresponding to 0.5mg/kg of escin Ia and 0.5mg/kg of isoescin Ia, respectively) and an i.v. dose (0.5mg/kg) or oral dose (4mg/kg) of pure escin Ia or isoescin Ia, respectively. At different time points, the concentrations of escin Ia and isoescin Ia in rat plasma were determined by LC-MS/MS method. Main pharmacokinetic parameters including t(1/2), MRT, CL, V(d), AUC and F were estimated by non-compartmental analysis using the TopFit 2.0 software package (Thomae GmbH, Germany) and statistical analysis was performed using the Student's t-test with P<0.05 as the level of significance. RESULTS: After administration of sodium escinate, the t(1/2) and MRT values for both escin Ia and isoescin Ia were larger than corresponding values for the compounds given alone. Absorption of escin Ia and isoescin Ia was very low with F values both <0.25%. Escin Ia and isoescin Ia were found to form the other isomer in vivo with the conversion of escin Ia to isoescin Ia being much extensive than from isoescin Ia to escin Ia. CONCLUSION: Comparison of the pharmacokinetics of escin Ia and isoescin Ia given alone and together in rat suggest that administration of herbal preparations of escin for clinical use may provide longer duration of action than administration of single isomers. The interconversion of escin Ia and isoescin Ia when given alone indicates that administration of one isomer leads to exposure to the other.

Asunto(s)

Aesculus , Escina/farmacocinética , Extractos Vegetales/farmacocinética , Administración Oral , Aesculus/química , Animales , Área Bajo la Curva , Disponibilidad Biológica , Cromatografía Liquida , Escina/análogos & derivados , Escina/sangre , Escina/aislamiento & purificación , Femenino , Inyecciones Intravenosas , Masculino , Extractos Vegetales/sangre , Ratas , Ratas Wistar , Semillas/química , Espectrometría de Masas en Tándem

RESUMEN

OBJECTIVE: To explore the feasibility of microdialysis techniqiue to be used in pharmacokinetic study of Chinese medicine, taking Shuanghuanglian as a model drug. METHOD: The samples were obtained by retrodialysis, determined by HPLC gradient elution to calculate the in vitro recovery rate (RR) of specific components. To study the difference of RR of a certain component in different dialysis mediums, and the effect of flow rates and concentration on RR. RESULT: Along with the increase of number of substances in the dialysis medium, the RR of specific components reduced. But the RR was independent of the concentration of the component in the dialysis medium. The RR reduced with the increasing flow rate in the same dialysis medium. CONCLUSION: The microdialysis technique can be used in pharmacokinetics study of Chinese medicine.

Asunto(s)

Medicamentos Herbarios Chinos/análisis , Microdiálisis/métodos , Calibración , Cromatografía Líquida de Alta Presión , Medicamentos Herbarios Chinos/aislamiento & purificación , Medicamentos Herbarios Chinos/farmacocinética , Estudios de Factibilidad

RESUMEN

The paper is to report the study of pharmacokinetics of transdermal administered nicotine in the brain of freely moving rat by using microdialysis with stable labeled isotope as internal standard. The pharmacokinetic behavior of nicotine in Sprague Dawley rat brain was investigated after intranasal administration (3.75 mg). Brain fluid samples were collected by intracerebral microdialysis with DL-nicotine as internal standard. Concentrations of nicotine and DL-nicotine in the sample were measured by HPLC-MS/MS. Main pharmacokinetic parameters were calculated and analyzed by Das 2.0 pharmacokinetic software. The recovery of nicotine and the delivery of DL-nicotine were the same. The fate of absorption and distribution was two compartment model and the values of t1/2alpha was 170.31 min, t1/2beta was 263.30 min and the AUC(0-infinity) was 2.75 x 10(5) microg x L(-1) min separately. DL-nicotine can be used to calibrate the recovery of nicotine, and the new method of stable isotope microdialysis can be used to study the pharmacokinetics of freely moving rat. It will make sense for the treatment of addiction of tobacco and provide a new thought for the research of pharmacokinetics-pharmacodynamic combination.

Asunto(s)

Encéfalo/metabolismo , Marcaje Isotópico/métodos , Microdiálisis/métodos , Nicotina/farmacocinética , Administración Cutánea , Administración Intranasal , Animales , Área Bajo la Curva , Cromatografía Líquida de Alta Presión , Deuterio , Femenino , Masculino , Nicotina/administración & dosificación , Ratas , Ratas Sprague-Dawley , Espectrometría de Masas en Tándem

RESUMEN

A rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous quantification of escin Ia and escin Ib in human plasma. After a solid-phase extraction (SPE), the analytes were separated on a Zorbax Extend C(18) column by isocratic elution with a mobile phase of methanol-acetonitrile-10 mm ammonium acetate (27:27:46, v/v/v) at a flow rate of 1.0 mL/min and analyzed by mass spectrometry in the positive ion multiple reaction monitoring mode. The precursor to product ion transitions of m/z 1131.8 → 807.6 was used to quantify escin Ia and escin Ib. Good linearity was achieved over a wide range of 2.00-900 ng/mL for escin Ia and 1.50-662 ng/mL for escin Ib. The intra- and inter-day precisions (as relative standard deviation) were less than 11% for each QC level of escin Ia and escin Ib. The accuracies (as relative error) were within ±5.27% for escin Ia and within ±4.07% for escin Ib. The method was successfully employed in a pharmacokinetic study after a single intravenous infusion administration of sodium aescinate injection containing 10 mg escin to each of the 10 healthy volunteers.

Asunto(s)

Cromatografía Liquida/métodos , Escina/sangre , Espectrometría de Masas en Tándem/métodos , Escina/administración & dosificación , Escina/aislamiento & purificación , Escina/farmacocinética , Humanos , Inyecciones Intravenosas , Extracción en Fase Sólida

RESUMEN

A rapid and sensitive bioassay based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of four isomeric escin saponins (escin Ia, escin Ib, isoescin Ia and isoescin Ib) in human plasma has been developed and validated. Sample preparation of plasma after addition of telmisartan as internal standard (I.S.) involved solid-phase extraction (SPE) on C18 cartridges. Separation was based on reversed phase chromatography using gradient elution with methanol-acetonitrile (50:50, v/v) and 10 mM ammonium acetate solution (pH 6.8). MS/MS detection in the positive ion mode used multiple reaction monitoring of the transition at m/z 1113.8-->807.6. Stability issues with the four saponins required the addition of formic acid to plasma samples prior to storage at -80 degrees C and analysis within 30 days. The method was linear at concentrations up to 10 ng/mL with correlation coefficients>0.996 for all analytes. The lower limit of quantitation (LLOQ) for all four saponins was 33 pg/mL. Intra- and inter-day precisions (as relative standard deviation) were all <15% and accuracies (as relative error) in the range -5.3% to 6.1%. The method was successfully applied to a pharmacokinetic study of escins in healthy volunteers after oral administration of sodium aescinate tablets containing 60 mg escin saponins.

Asunto(s)

Cromatografía Liquida/métodos , Escina/sangre , Escina/farmacocinética , Espectrometría de Masas en Tándem/métodos , Administración Oral , Adulto , Escina/administración & dosificación , Escina/química , Humanos , Isomerismo , Límite de Detección , Masculino , Reproducibilidad de los Resultados , Factores de Tiempo , Adulto Joven