- Synthesis of new verapamil analogues and their evaluation in combination with rifampicin against Mycobacterium tuberculosis and molecular docking studies in the binding site of efflux protein Rv1258c
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New verapamil analogues were synthesized and their inhibitory activities against Mycobacterium tuberculosis H37Rv determined in vitro alone and in combination with rifampicin (RIF). Some analogues showed comparable activity to verapamil and exhibited better synergies with RIF. Molecular docking studies of the binding sites of Rv1258c, a M. tuberculosis efflux protein previously implicated in intrinsic resistance to RIF, suggested a potential rationale for the superior synergistic interactions observed with some analogues.
- Singh, Kawaljit,Kumar, Malkeet,Pavadai, Elumalai,Naran, Krupa,Warner, Digby F.,Ruminski, Peter G.,Chibale, Kelly
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p. 2985 - 2990
(2014/06/24)
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- Comparison of triple quadrupole, hybrid linear ion trap triple quadrupole, time-of-flight and LTQ-orbitrap mass spectrometers in drug discovery phase metabolite screening and identification in vitro - amitriptyline and verapamil as model compounds
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Liquid chromatography in combination with mass spectrometry (LC/MS) is a superior analytical technique for metabolite profiling and identification studies performed in drug discovery and development laboratories. In the early phase of drug discovery the analytical approach should be both time- and cost-effective, thus providing as much data as possible with only one visit to the laboratory, without the need for further experiments. Recent developments in mass spectrometers have created a situation where many different mass spectrometers are available for the task, each with their specific strengths and drawbacks. We compared the metabolite screening properties of four main types of mass spectrometers used in analytical laboratories, considering both the ability to detect the metabolites and provide structural information, as well as the issues related to time consumption in laboratory and thereafter in data processing. Human liver microsomal incubations with amitriptyline and verapamil were used as test samples, and early-phase 'one lab visit only' approaches were used with all instruments. In total, 28 amitriptyline and 69 verapamil metabolites were found and tentatively identified. Time-of-flight mass spectrometry (TOFMS) was the only approach detecting all of them, shown to be the most suitable instrument for elucidating as comprehensive metabolite profile as possible leading also to lowest overall time consumption together with the LTQ-Orbitrap approach. The latter however suffered from lower detection sensitivity and false negatives, and due to slow data acquisition rate required slower chromatography. Approaches with triple quadrupole mass spectrometry (QqQ) and hybrid linear ion trap triple quadrupole mass spectrometry (Q-Trap) provided the highest amount of fragment ion data for structural elucidation, but, in addition to being unable to produce very high-important accurate mass data, they suffered from many false negatives, and especially with the QqQ, from very high overall time consumption.
- Rousu, Timo,Herttuainen, Jukka,Tolonen, Ari
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experimental part
p. 939 - 957
(2011/10/19)
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- A panel of cytochrome P450 BM3 variants to produce drug metabolites and diversify lead compounds
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Herein we demonstrate that a small panel of variants of cytochrome P450 BM3 from Bacillus megaterium covers the breadth of reactivity of human P450s by producing 12 of 13 mammalian metabolites for two marketed drugs, verapamil and astemizole, and one research compound. The most active enzymes support preparation of individual metabolites for preclinical bioactivity and toxicology evaluations. Underscoring their potential utility in drug lead diversification, engineered P450 BM3 variants also produce novel metabolites by catalyzing reactions at carbon centers beyond those targeted by animal and human P450s. Production of a specific metabolite can be improved by directed evolution of the enzyme catalyst. Some variants are more active on the more hydrophobic parent drug than on its metabolites, which limits production of multiply-hydroxylated species, a preference that appears to depend on the evolutionary history of the P450 variant.
- Sawayama, Andrew M.,Chen, Michael M. Y.,Kulanthaivel, Palaniappan,Kuo, Ming-Shang,Hemmerle, Horst,Arnold, Frances H.
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supporting information; scheme or table
p. 11723 - 11729
(2010/04/29)
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- Process for the preparation of basically substituted phenylacetonitriles
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A simplified process for the preparation of basically substituted phenylacetonitriles, in particular of verapamil, is described. This process is carried out with fewer stages and higher yields than the known processes according to the state of the art.
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