Development and Validation of LC-UV for Simultaneous Estimation of Rosiglitazone and Glimepride in Human Plasma

A simple, sensitive and specific liquid chromatographic method with UV detection (228 nm) was developed for the simultaneous estimation of rosiglitazone and glimepride in human plasma. Rosiglitazone and glimepride were extracted from plasma using liquid–liquid extraction. Separation was achieved with an RP C₁₈ Column using a mixture of phosphate buffer (50 mM) with octane sulfonic acid (10 mM), methanol and acetonitrile as a mobile phase (55:10:35, v/v). pH was adjusted to 7.0. Amlodipine was used as an internal standard (IS). LOD of the method was found to be 20 ng mL⁻¹ for both drugs. Results were linear over the studied range 40.994–2007.556 ng mL⁻¹ for rosiglitazone (r ² ≥ 0.99) and 41.066–2094.84 ng mL⁻¹ for glimepride( r ² ≥ 0.99). The method was found to be simple, selective, precise and reproducible for the estimation of both drugs from spiked human plasma.

     

Determination of quinapril and quinaprilat in human plasma by ultraperformance liquid chromatography–electrospray ionization mass spectrometry

A novel, specific and sensitive ultraperformance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) method was developed for the simultaneous determination of quinapril and its active metabolite quinaprilat in human plasma. The method involves a simple, one‐step extraction procedure coupled with an Acquity UPLC? BEH C₁₈ column (100 × 2.1 mm, i.d., 1.7 µm) with isocratic elution at a flow‐rate of 0.2 mL/min and lisinopril as the internal standard. Detection was performed on a triple‐quadrupole tandem mass spectrometer in multiple reaction monitoring mode via electrospray ionization. Using 250 µL plasma, the methods were validated over the concentration range 5.010–500.374 ng/mL for quinapril and 10.012–1000 ng/mL for quinaprilat, with a lower limit of quantification of 5.010 ng/mL for quinapril and 10.012 ng/mL for quinaprilat. The intra‐ and inter‐day precision and accuracy were within 10.0%. The recovery was 85.8, 62.6 and 61.3% for quinapril, quinaprilat and lisinopril, respectively. Total run time was 3.0 min only. Copyright © 2008 John Wiley & Sons, Ltd.     

Size-exclusion capillary electrochromatographic separation of polysaccharides using polymeric stationary phases

We report the successful size-based separations of large, neutral polysaccharides using capillary electrochromatography (CEC). As the polysaccharides possessed little chromophore for photometric detection, two separate approaches were taken. In the first approach, indirect detection was combined with size-exclusion chromatography using a sulfonated polystyrene/divinylbenzene stationary phase. The separations were performed using a 300 A pore size stationary phase under aqueous conditions. Non-size based interactions were minimal using this material, resulting in an effective calibration range of molecular masses 180 to 112 000 g.mol(-1) for pullulans. In the second approach, the polysaccharides were derivatized with phenylisocyanate and were subsequently separated on columns made using a combination of high capacity ion-exchanger and a neutral polystyrene/divinylbenzene material of various pore sizes. The sulfonated ion-exchange phase provided the electroosmotic flow, while the mixed pore size material provided the extended calibration range. The linear range for this primarily nonaqueous system using tetrahydrofuran was determined to be from molecular masses 738 to 404 000 g.mol(-1) of the original, untagged pullulan. This approach overcame the limited solubility issue associated with analysis of some polysaccharides. Analysis of pullulan and amylose samples by CEC correlated well with results obtained by conventional high-performance liquid chromatography (HPLC). The size-exclusion electrochromatographic separations provide an alternative mode for determining the relative molecular weights of polysaccharides with reduced sample and solvent consumption, as well as analysis times.     

Branching fractions of tau leptons to three charged hadrons

From electron-positron collision data collected with the CLEO detector operating at Cornell Electron Storage Ring near sqrt[s]=10.6 GeV, improved measurements of the branching fractions for tau decays into three explicitly identified hadrons and a neutrino are presented as B(tau(-)-->pi(-)pi(+)pi(-)nu(tau))=(9.13+/-0.05+/-0.46)%, B(tau(-)-->K-pi(+)pi(-)nu(tau))=(3.84+/-0.14+/-0.38) x 10(-3), B(tau(-)-->K-K+pi(-)nu(tau))=(1.55+/-0.06+/-0.09) x 10(-3), and B(tau(-)-->K-K+K-nu(tau))<3.7 x 10(-5) at 90% C.L., where the uncertainties are statistical and systematic, respectively.     

Evidence of New States Decaying into Xi(*)(c)pi

Using 13.7 fb(-1) of data recorded by the CLEO detector at Cornell Electron Storage Ring, we report evidence of two new charmed baryons: one decaying into Xi(0')(c)pi(+) with the subsequent decay Xi(0')(c)-->Xi(0)(c)gamma, and its isospin partner decaying into Xi(+')(c)pi(-) followed by Xi(+')(c)-->Xi(+)(c)gamma. We measure the following mass differences for the two states: M(Xi(0)(c)gammapi(+))-M(Xi(0)(c)) = 318.2+/-1.3+/-2.9 MeV and M(Xi(+)(c)gammapi(-))-M(Xi(+)(c)) = 324.0+/-1.3+/-3.0 MeV. We interpret these new states as the J(P) = 1 / 2(-) Xi(c1) particles, the charmed-strange analogs of the Lambda(+)(c1)(2593).     

Search for CP violation in tau--> K(pi)nu(tau) decays

We search and find no evidence for CP violation in tau decays into the K(pi)nu(tau) final state. We provide limits on the imaginary part of the coupling constant Lambda describing a relative contribution of the CP violating processes with respect to the standard model to be -0.172相似文献