605 research outputs found
Gabapentin Bioequivalence Study: Quantification By Liquid Chromatography Coupled To Mass Spectrometry
The study was performed to compare the bioavailability of two gabapentin 400 mg capsule formulation (Gabapentin from Arrow Farmacêutica S/A as test formulation and Neurontin ® from Pfizer, Brazil, as reference formulation) in 26 volunteers of both sexes. The study was conducted open with randomized two period crossover design and a one week wash out period. Plasma samples were obtained over a 48 hour interval. The gabapentin was analyzed by LC/MS/MS, in the presence of pracetamole as internal standard. With plasma concentration vs. time curves, data obtained from this metabolite, the following pharmacokinetics parameters were obtained: AUC 0-t, AUC 0-inf and C max. Geometric mean of gabapentin/Neurontin ® 400 mg individual percent ratio was 100.58% AUC 0-t, 101.35% for AUC 0-inf and 97.76% for C max. The 90% confidence intervals were 92.00 - 109.95%, 93.00 - 110.44%, 88.41 - 108.10%, respectively. Since the 90% confidence intervals for C max, AUC 0-t and AUC 0 -inf were within the 80 - 125% interval proposed by Food and Drug Administration, it was concluded that gabapentin 400 mg capsule was bioequivalent to Neurontin ® 400 mg capsule according to both the rate and extent of absorption. © 2011 Junior EA, et al.38187190Wattananat, T., Akarawut, W., Validated LC-MS-MS Method for the Determination of Gabapentin in Human Plasma: Application to a Bioequivalence Study (2009) J Chromatogr Sci, 47, pp. 868-871Stewart, B.H., Kagler, A.R., Thompson, P.R., Bockbrader, H.N., A saturable transport mechanism in the intestinal absorption of gabapentin is the underlying cause of the lack of proportionality between increasing dose and drug levels in plasma (1993) Pharma Res, 10, pp. 276-281McLean, M.J., Gabapentin in the management of convulsive disorders (1999) Epilepsia, 40, pp. 39-50Goa, K.L., Sorkin, E.M., Gabapentin: A review of its pharmacological properties and clinical potential in epilepsy (1993) Drugs, 46, pp. 409-427Zhu, Z., Neirinck, L., High-performance liquid chromatographic method for the determination of gabapentin in human plasma (2002) J Chromatogr B Analyt Technol Biomed Life Sci, 779, pp. 307-312Sagirli, O., Cetin, S.M., Determination of gabapentin in human plasma and urine by high-performance liquid chromatography with UV-vis detection (2006) J Pharm Biomed Anal, 42, pp. 618-624Jalalizadeh, H., Souri, E., Tehrani, M.B., Jahangiri, A., Validated HPLC method for the determination of gabapentin in human plasma using precolumn derivatization with 1-fluoro-2,4-dinitrobenzene and its application to a pharmacokinetic study (2007) J Chromatogr B Analyt Technol Biomed Life Sci, 854, pp. 43-47Forrest, G., Sills, G.J., Leach, J.P., Brodie, M.J., Determination of gabapentin in plasma by high-performance liquid chromatography (1996) J Chromatogr B Analyt Technol Biomed Life Sci, 681, pp. 421-425Tang, P.H., Miles, M.V., Glauser, T.A., Degrauw, T., Automated microanalysis of gabapentin in human serum by high-performance liquid chromatography with fluorometric detection (1999) J Chromatogr B Analyt Technol Biomed Life Sci, 727, pp. 125-129Hassan, E.M., Belal, F., Al-Deeb, O.A., Khalil, N.Y., Spectrofluorimetric determination of vigabatrin and gabapentin in dosage forms and spiked plasma samples through derivatization with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (2001) J. AOAC Int., 84, pp. 1017-1024Gauthier, D., Gupta, R., Determination of gabapentin in plasma by liquid chromatography with fluorescence detection after solid-phase extraction with a C18 column (2002) Clin Chem, 48, pp. 2259-2261Chung, T.C., Tai, C.T., Wu, H.L., Simple and sensitive liquid chromatographic method with fluorimetric detection for the analysis of gabapentin in human plasma (2006) J Chromatogr A, 119, pp. 294-298Bahrami, G., Kiani, A., Sensitive high-performance liquid chromatographic quantitation of gabapentin in human serum using liquid-liquid extraction and pre-column derivatization with 9-fluorenylmethyl chloroformate (2006) J Chromatogr B Analyt Technol Biomed Life Sci, 835, pp. 123-126Krivanek, P., Koppatz, K., Turnheim, K., Simultaneous isocratic HPLC determination of vigabatrin and gabapentin in human plasma by dansyl derivatization (2003) Ther Drug Monit, 25, pp. 374-377Chang, S.Y., Wang, F.Y., Simple and sensitive liquid chromatographic method with fluorimetric detection for the analysis of gabapentin in human plasma (2004) J Chromatogr B Analyt Technol Biomed Life Sci, 799, pp. 265-270Wolf, C.E., Saady, J.J., Poklis, A., Determination of gabapentin in serum using solid phase extraction and gas-liquid chromatography (1996) J Anal Toxicol, 20, pp. 498-501Kushnir, M.M., Cossett, J., Brown, P.I., Urry, F.M., Analysis of gabapentin in serum and plasma by solid-phase extraction and gas chromatography-mass spectrometry for therapeutic drug monitoring (1999) J Anal Toxicol, 23, pp. 1-6Borrey, D.C., Godderis, K.O., Engelrelst, V.I., Bernard, D.R., Langlois, M.R., Quantitative determination of vigabatrin and gabapentin in human serum by gas chromatography-mass spectrometry (2005) Clin Chim Acta, 354, pp. 147-151Gambelunghe, C., Mariucci, G., Tantucci, M., Ambrosini, M.V., Gas chromatography-tandemmass spectrometry analysis of gabapentin in serum (2005) Biomed Chromatogr, 19, pp. 63-67Matar, K.M., Abdel-Hamid, M.E., Rapid tandem mass spectrometric method for determination of gabapentin in human plasma (2005) Chromatographia, 61, pp. 499-504Ramakrishna, N.V.S., Vishwottam, K.N., Koteshwara, M., Maroj, S., Santosh, M., Rapid quantification of gabapentin in human plasma by liquid chromatography/tandemmass spectrometry (2006) J Pharm Biomed Anal, 40, pp. 360-368Ifa, D.R., Falci, M., Moraes, M.E., Bezerra, F.A., Moraes, M.O., Gabapentin quantification in human plasma by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry. Application to bioequivalence study (2001) J Mass Spectrom, 36, pp. 188-194Ji, H.Y., Jeong, D.W., Kim, Y.H., Kim, H.H., Yoon, Y.S., Determination of gabapentin in human plasma using hydrophilic interaction liquid chromatography with tandem mass spectrometry (2006) Rapid Commun Mass Spectrom, 20, pp. 2127-2132Carlsson, K.C., Reubsaet, J.L., Sample preparation and determination of gabapentin in venous and capillary blood using liquid chromatography-tandem mass spectrometry (2004) J Pharm Biomed Anal, 34, pp. 415-423Park, J.H., Jhee, O.H., Park, S.H., Lee, J.S., Lee, M.H., Validated LC-MS/ MS method for quantification of gabapentin in human plasma: Application to pharmacokinetic and bioequivalence studies in Korean volunteers (2007) Biomed Chromatogr, 21, pp. 829-83
Klein tunneling in graphene: optics with massless electrons
This article provides a pedagogical review on Klein tunneling in graphene,
i.e. the peculiar tunneling properties of two-dimensional massless Dirac
electrons. We consider two simple situations in detail: a massless Dirac
electron incident either on a potential step or on a potential barrier and use
elementary quantum wave mechanics to obtain the transmission probability. We
emphasize the connection to related phenomena in optics, such as the
Snell-Descartes law of refraction, total internal reflection, Fabry-P\'erot
resonances, negative refraction index materials (the so called meta-materials),
etc. We also stress that Klein tunneling is not a genuine quantum tunneling
effect as it does not necessarily involve passing through a classically
forbidden region via evanescent waves. A crucial role in Klein tunneling is
played by the conservation of (sublattice) pseudo-spin, which is discussed in
detail. A major consequence is the absence of backscattering at normal
incidence, of which we give a new shorten proof. The current experimental
status is also thoroughly reviewed. The appendix contains the discussion of a
one-dimensional toy model that clearly illustrates the difference in Klein
tunneling between mono- and bi-layer graphene.Comment: short review article, 18 pages, 14 figures; v3: references added,
several figures slightly modifie
EEG spike source localization before and after surgery for temporal lobe epilepsy: a BOLD EEG-fMRI and independent component analysis study
A Green's function approach to transmission of massless Dirac fermions in graphene through an array of random scatterers
We consider the transmission of massless Dirac fermions through an array of
short range scatterers which are modeled as randomly positioned -
function like potentials along the x-axis. We particularly discuss the
interplay between disorder-induced localization that is the hallmark of a
non-relativistic system and two important properties of such massless Dirac
fermions, namely, complete transmission at normal incidence and periodic
dependence of transmission coefficient on the strength of the barrier that
leads to a periodic resonant transmission. This leads to two different types of
conductance behavior as a function of the system size at the resonant and the
off-resonance strengths of the delta function potential. We explain this
behavior of the conductance in terms of the transmission through a pair of such
barriers using a Green's function based approach. The method helps to
understand such disordered transport in terms of well known optical phenomena
such as Fabry Perot resonances.Comment: 22 double spaced single column pages. 15 .eps figure
System Size and Energy Dependence of Jet-Induced Hadron Pair Correlation Shapes in Cu+Cu and Au+Au Collisions at sqrt(s_NN) = 200 and 62.4 GeV
We present azimuthal angle correlations of intermediate transverse momentum
(1-4 GeV/c) hadrons from {dijets} in Cu+Cu and Au+Au collisions at sqrt(s_NN) =
62.4 and 200 GeV. The away-side dijet induced azimuthal correlation is
broadened, non-Gaussian, and peaked away from \Delta\phi=\pi in central and
semi-central collisions in all the systems. The broadening and peak location
are found to depend upon the number of participants in the collision, but not
on the collision energy or beam nuclei. These results are consistent with sound
or shock wave models, but pose challenges to Cherenkov gluon radiation models.Comment: 464 authors from 60 institutions, 6 pages, 3 figures, 2 tables.
Submitted to Physical Review Letters. Plain text data tables for the points
plotted in figures for this and previous PHENIX publications are (or will be)
publicly available at http://www.phenix.bnl.gov/papers.htm
Estudo de simulação de modelos lineares mistos com distribuição normal contaminada no melhoramento genético animal
Genetic variability in natural populations of Zeyheria montana mart. from the Brazilian Cerrado
Valor nutritivo de silagens de milho (Zea mays L.) produzidas com inoculantes enzimo-bacterianos
Caracterização da flora e estrutura do estrato arbustivo-arbóreo de um cerrado no Pantanal de Poconé, MT
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