A validated liquid chromatographic method for estimation of solasodine in various Solanum species and market formulations

This paper describes an improved liquid chromatographic (LC) method involving a prechromatographic derivatization step for the estimation of solasodine from berries of various Solanum species, market samples of Solanum xanthocarpum herb, extract, and its market formulations. Solasodine has heterocyclic nitrogen but has no conjugated double bonds in its structure. However, in all reported LC methods, detection was made in the ultraviolet range of 200-213 nm. In the present study, a prechromatographic derivatization of solasodine was done by forming an ion-pair complex of the heterocyclic nitrogen using the acidic dye methyl orange and acetate buffer of pH 4.7. Detection could be made in the visible range at 530 nm in this method. The method was validated and successfully applied to determine solasodine content in various plant samples and polyherbal formulations. The relative standard deviation was found to be 0.025% for system precision, and 0.8% for the linearity of the method, and the correlation coefficient was 0.999. Plant samples and market formulations were analyzed and found to contain solasodine in the range of 0.113-0.227% (w/w) on a fresh weight basis in berries; 0.3-1.278% (w/w) and 0.412% (w/w) on a dry weight basis in S. xanthocarpum herb powder and extract, respectively; and 0.245-0.525% (w/w) on dry weight basis in formulations containing S. xanthocarpum herb powder. No matrix interference was encountered. The method was found to be accurate, with a mean recovery of 100.5 +/- 0.83%. The method has good reproducibility and was found to be suitable for estimation of solasodine.     

Rapid ultraperformance liquid chromatography–tandem mass spectrometry method for quantification of oxcarbazepine and its metabolite in human plasma

A rapid and sensitive ultraperformance liquid chromatography tandem mass spectrometry assay was developed for the simultaneous analysis of oxcarbazepine and its main metabolite in human plasma. The assay involves a simple solid‐phase extraction procedure of 0.3 mL of human plasma and analysis was performed on a triple‐quadrupole tandem mass spectrometer in multiple reaction monitoring mode via electrospray ionization. Separation was achieved on an Acquity UPLC™ BEH C₁₈ column (50 × 2.1 mm, i.d., 1.7 µm) with isocratic elution at a flow‐rate of 0.25 mL/min and imipramine was used as the internal standard. The standard calibration curve was linear over the range 9.580–5070.205 ng/mL for oxcarbazepine (OXC) and 19.444–10290.800 ng/mL for 10,11‐dihydro‐10‐hydroxycarbamazepine (MHD), expressed by the linear correlation coefficient r², which was better than 0.995 for OXC and MHD. The intra‐ and inter‐day precision and accuracy of the quality control samples were within 10.0%. The recoveries were 81.0, 89.6 and 66.6% for OXC, MHD and imipramine, respectively. The total run time was 1.5 min only for each sample, which makes it possible to analyze more than 350 samples per day. Copyright © 2010 John Wiley & Sons, Ltd.     

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.     

Density and Viscosity of Alkyl Acetates + Aromatic Hydrocarbons at (303.15 and 313.15) K

Densities and viscosities have been determined for binary mixtures of isopropyl acetate or isobutyl acetate with o-xylene, m-xylene, p-xylene and ethyl benzene at (303.15 and 313.15) K for the entire composition range. The excess molar volumes and deviations in viscosity have been calculated from the experimental values. The variations of these parameters, with composition of the mixtures and temperature, have been discussed in terms of molecular interactions occurring in these mixtures. Further, the viscosities of these binary mixtures were calculated theoretically from their corresponding pure component data by using empirical relations, and the results were compared with the experimental findings.     

Densities,Viscosities and Speeds of Sound of Binary Mixtures of Ethyl Benzoate + Hydrocarbons at (303.15, 308.15 and 313.15) K

Densities, viscosities and speeds of sound of binary mixtures of ethyl benzoate with cyclohexane, n-hexane, heptane and octane have been measured over the entire range of composition at (303.15, 308.15 and 313.15) K and at atmospheric pressure. From these experimental values, excess molar volume (V ^E), deviation in viscosity (Δη) and deviation in isentropic compressibility (ΔK _s) have been calculated. The viscosities of binary mixtures were calculated theoretically from the pure component data by using various empirical and semi-empirical relations and the results compared with the experimental findings.     

C-H activations on a 1H-1,4-benzodiazepin-2(3H)-one template

Air stable benzodiazepine containing palladacycles were synthesized by a C-H activation reaction and studied by mass spectrometry and X-ray crystallography. Catalytic C-H functionalizations of 1-methyl-5-phenyl-1H-1,4-benzodiazepin-2(3H)-one with diphenyliodonium hexafluorophosphate led to a mixture, which included the starting material and the expected product 1-methyl-5-(2′-biphenyl)-1H-1,4-benzodiazepin-2(3H)-one.     

Determination of fenofibric acid in human plasma by ultra performance liquid chromatography–electrospray ionization mass spectrometry: application to a bioequivalence study

A rapid, specific and sensitive ultra‐performance liquid chromatography tandem mass spectrometry method was developed for the determination of fenofibric acid in human plasma. The method involves simple, one‐step liquid–liquid extraction procedure coupled with an Acquity UPLC^TM BEH C₁₈ column (50 × 2.1 mm, i.d., 1.7 µm) with isocratic elution at a flow‐rate of 0.2 mL/min and mefenamic acid was used as the internal standard. The Quattro Premier XE mass spectrometry was operated under the multiple reaction‐monitoring mode using the electrospray ionization technique. Using 250 µL plasma, the methods were validated over the concentration rang 0.05–7.129 µg/mL, with a lower limit of quantification of 0.05 µg/mL. The intra‐ and inter‐day precision and accuracy were within 9.3%. The recovery was 66.7% and 52.6% for fenofibric acid, and mefenamic acid, respectively. Total run time was 1.8 min only for each sample, which makes it possible to analyze more than 350 samples per day. Copyright © 2009 John Wiley & Sons, Ltd.     

Development and validation of amitriptyline and its metabolite in human plasma by ultra performance liquid chromatography-tandem mass spectrometry and its application to a bioequivalence study

A method based on ultra performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) in combination with solid‐phase extraction for sample pretreatment has been developed for the simultaneous analysis of amitriptyline and its main metabolite in human plasma. The extraction of the analytes from plasma samples was carried out by means of a selective SPE procedure using hydrophilic–lipophilic balance cartridges. The assay involves a simple solid‐phase extraction (SPE) procedure of 0.2 mL of human plasma and analysis was performed on a triple‐quadrupole tandem mass spectrometer by multiple reactions monitoring (MRM) mode via electrospray ionization (ESI). The standard calibration curve was linear over the ranges 0.370–95.539 ng/mL for amitriptyline and 0.365–94.374 ng/mL for nortriptyline, expressed by the linear correlation coefficient r², which was better than 0.995 for both. The intra‐ and inter‐day precision and accuracy of the quality control samples were within 10.0%. The recovery was 85.3, 88.4 and 80.7% for amitriptyline, nortriptyline and doxepin respectively. Total run time was 1.2 min only for each sample, which makes it possible to analyze more than 400 samples per day. The method was highly reproducible and gave peaks with excellent chromatography properties. Copyright © 2010 John Wiley & Sons, Ltd.     

Stereoselective Synthesis of (Z)-1-Benzhydryl-4-cinnamylpiperazines via the Wittig Reaction

A synthetic method of producing (E)- and (Z)-isomers of 1-benzhydryl-4-cinnamylpiperazines in a specific ratio from corresponding benzhydrylpiperazine is described. Of the three compounds synthesized (5a–c), the ratio of E/Z-isomers remained around 15:85. The key intermediates, 1-benzhydryl-4-(2,2-dimethoxyethyl)piperazine derivatives (3a–c), were prepared by nucleophilic substitution reaction of benzhydrylpiperazines (2a–c) with chloroacetaldehyde dimethylacetal in good yield (up to 88%). Hydrolysis of 3a–c gave the corresponding aldehydes 4a–c, which when subjected to the Wittig reaction followed by column purification to afford 1a–c (E-isomers) and 6a–c (Z-isomers) in pure form. The isolated compounds were characterized by NMR and mass spectral analysis.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]