Publications by authors named "Subrahmanyam Vangala"

The fact that animal models fail to replicate human disease faithfully is now being widely accepted by researchers across the globe. As a result, they are exploring the use of alternatives to animal models. The time has come to refine our experimental practices, reduce the numbers and eventually replace the animals used in research with human-derived and human-relevant 3-D disease models.

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The polyphenol E- and Z-gugggulsterone (GS) is an antagonist ligand for the Farnesoid X Receptor (FXR) and known to possess potent hypolipidemic properties as shown in various preclinical and clinical studies. In the present study, we examined drug-like properties of GS by assessing the isomers plasma protein binding, metabolic stability, CYP profiling, CYP inhibition, and phase I and II metabolite identification of GS using liver microsomes and S9 fractions. GS followed Lipinski and Veber rules and were substrates of CYP3A CYP2C19 and CYP2D6 isoforms.

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Background: Drug transporters function as gatekeepers and modulate drug access into body and various tissues. Thus, a thorough and precise understanding of transporter liability for compound uptake and efflux is critical during drug development.

Methods: In the present study, we assessed the apparent permeability (Papp) and compared efflux ratio of various compounds in stably transfected Madin-Darby Canine Kidney (MDCKII) cells overexpressing human P-gp (MDCKII-MDR1), human BCRP (MDCKII-BCRP), wild-type (MDCKII-WT), and Caco-2 cell monolayers.

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Anticancer efficacy of ginger phenolics (GPs) has been demonstrated in various in vitro assays and xenograft mouse models. However, only sub-therapeutic plasma concentrations of GPs were detected in human and mouse pharmacokinetic (PK) studies. Intriguingly, a significant portion of GPs occurred as phase II metabolites (mainly glucuronide conjugates) in plasma.

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Modern drug discovery efforts have had mediocre success rates with increasing developmental costs, and this has encouraged pharmaceutical scientists to seek innovative approaches. Recently with the rise of the fields of systems biology and metabolomics, network pharmacology (NP) has begun to emerge as a new paradigm in drug discovery, with a focus on multiple targets and drug combinations for treating disease. Studies on the benefits of drug combinations lay the groundwork for a renewed focus on natural products in drug discovery.

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Guggulsterone is a racemic mixture of two stereoisomers (E- and Z-), obtained from the gum resin of Commiphora mukul and it is marketed as an antihyperlipidemic drug. The aim of our study was to assess the in vitro and in vivo absorption, distribution, metabolism, and excretion (ADME) properties namely solubility, in vitro metabolism, plasma protein binding and oral pharmacokinetic studies of E- and Z-guggulsterone. In vitro metabolism experiments were performed by using rat liver and intestinal microsomes.

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Noscapine (Nos), an antitussive benzylisoquinoline opium alkaloid, is a non-toxic tubulin-binding agent currently in Phase II clinical trials for cancer chemotherapy. While preclinical studies have established its tumor-inhibitory properties in various cancers, poor absorptivity and rapid first-pass metabolism producing several uncharacterized metabolites for efficacy, present an impediment in translating its efficacy in humans. Here we report novel formulations of Nos in combination with dietary agents like capsaicin (Cap), piperine (Pip), eugenol (Eu) and curcumin (Cur) known for modulating Phase I and II drug metabolizing enzymes.

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Phytochemical complexity of plant extracts may offer health-promoting benefits including chemotherapeutic and chemopreventive effects. Isolation of 'most-active fraction' or single constituents from whole extracts may not only compromise the therapeutic efficacy but also render toxicity, thus emphasizing the importance of preserving the natural composition of whole extracts. The leaves of Annona muricata, commonly known as Graviola, are known to be rich in flavonoids, isoquinoline alkaloids and annonaceous acetogenins.

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Natural and complementary therapies in conjunction with mainstream cancer care are steadily gaining popularity. Ginger extract (GE) confers significant health-promoting benefits owing to complex additive and/or synergistic interactions between its bioactive constituents. Recently, we showed that preservation of natural "milieu" confers superior anticancer activity on GE over its constituent phytochemicals, 6-gingerol (6G), 8-gingerol (8 G), 10-gingerol (10 G) and 6-shogaol (6S), through enterohepatic recirculation.

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Phytochemical complexity of plant foods confers health-promoting benefits including chemopreventive and anticancer effects. Isolating single constituents from complex foods may render them inactive, emphasizing the importance of preserving the natural composition of whole extracts. Recently, we demonstrated in vitro synergy among the most abundant bioactive constituents of ginger extract (GE), viz.

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Background: The current practice of using calibration curves with narrow concentration ranges during bioanalysis of new chemical entities has some limitations and is time consuming. In the present study we describe a split calibration curve approach, where sample dilution and repeat analysis can be avoided without compromising the quality and integrity of the data obtained.

Results: A split calibration curve approach is employed to determine the drug concentration in plasma samples with accuracy and precision over a wide dynamic range of approximately 0.

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Extensive first-pass metabolism can significantly limit a drug's oral exposure levels. In this work, we introduce an innovative approach for increasing the oral bioavailability of a drug that undergoes extensive reversible glucuronidation and enterohepatic recirculation through intraduodenal coadministration of the deconjugating enzyme β-glucuronidase. Intraduodenal administration of JNJ-10198409 (10 mg/kg) with β-glucuronidase (34,000-140,000 units/kg) to catheterized rats resulted in a significant increase (p < 0.

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Pharmacogenomic (PGx) research on the absorption, distribution, metabolism, and excretion (ADME) properties of drugs has begun to have impact for both drug development and utilization. To provide a cross-industry perspective on the utility of ADME PGx, the Pharmaceutical Research and Manufacturers of America (PhRMA) conducted a survey of major pharmaceutical companies on their PGx practices and applications during 2003-2005. This white paper summarizes and interprets the results of the survey, highlights the contributions and applications of PGx by industrial scientists as reflected by original research publications, and discusses changes in drug labels that improve drug utilization by inclusion of PGx information.

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Application of "omics" technology during drug discovery and development is rapidly evolving. This review evaluates the current status and future role of "metabonomics" as a tool in the drug development process to reduce the safety-related attrition rates and bridge the gaps between preclinical and clinical, and clinical and market. Particularly, the review looks at the knowledge gap between the pharmaceutical industry and pediatric hospitals, where metabonomics has been successfully applied to screen and treat newborn babies with inborn errors of metabolism.

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Performance evaluation of accurate mass measurement by the LTQ/Orbitrap, at a resolving power of 60,000 and in external calibration mode, indicated that the Orbitrap is capable of providing high mass accuracy of <2 ppm for over 24 h post-calibration. This, together with limited trade-off between sensitivity and resolving power plus a wide dynamic range for mass accuracy, suggested that the LTQ/Orbitrap is an ideal analytical tool for structural elucidation of metabolites. The application of the LTQ/Orbitrap to identification of human liver microsomal metabolites of carvedilol was evaluated, using parent mass list triggered data-dependent multiple-stage accurate mass analysis, at a resolving power of 60,000 in external calibration mode.

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Various phosphodiesterase (PDE) 3,4 and 5 inhibitors have been compared with glucagon for their effectiveness at increasing hepatocyte cAMP, glycogenolysis and gluconeogenesis. Preincubation of isolated hepatocytes with PDE 3 and 4 inhibitors (50 microM) for 2 h induced significant increases in cellular cAMP level. The order of effectiveness was: glucagon (78%), V11294A (42%), rolipram (40%), milrinone (36%), CDP-840 (33%), R(0) 20-1724 (31%), papaverine (27%), isobutylmethylxanthine (28%), isoliquiritigenin (25%), theophylline (22%), and amrinone (22%).

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