Stereoselective Pharmacokinetics and Chiral Inversions of Some Chiral Hydroxy Group Drugs

Background: Chiral safety, especially chiral drug inversion in vivo, is the top priority of current scientific research. Medicine researchers and pharmacists often ignore that one enantiomer will be converted or partially converted to another enantiomer when it is ingested in vivo. So that, in the context that more than 50% of the listed drugs are chiral drugs, it is necessary and important to pay attention to the inversion of chiral drugs. Methods: The metabolic and stereoselective pharmacokinetic characteristics of seven chiral drugs with one chiral center in the hydroxy group were reviewed in vivo and in vitro including the possible chiral inversion of each drug enantiomer. These seven drugs include (S)-Mandelic acid, RS-8359, Tramadol, Venlafaxine, Carvedilol, Fluoxetine and Metoprolol. Results: The differences in stereoselective pharmacokinetics could be found for all the seven chiral drugs, since R and S isomers often exhibit different PK and PD properties. However, not every drug has shown the properties of one direction or two direction chiral inversion. For chiral hydroxyl group drugs, the redox enzyme system may be one of the key factors for chiral inversion in vivo. Conclusion: In vitro and in vivo chiral inversion is a very complex problem and may occur during every process of ADME. Nowadays, research on chiral metabolism in the liver has the most attention, while neglecting the chiral transformation of other processes. Our review may provide the basis for the drug R&D and the safety of drugs in clinical therapy.

Testing a non-perturbative mechanism for elementary fermion mass generation: lattice setup

In this contribution we lay down a lattice setup that allows for the nonperturbative study of a field theoretical model where a SU(2) fermion doublet, subjected to non-Abelian gauge interactions, is also coupled to a complex scalar field doublet via a Yukawa and an “irrelevant” Wilson-like term. Using naive fermions in quenched approximation and based on the renormalizedWard identities induced by purely fermionic chiral transformations, lattice observables are discussed that enable: a) in theWigner phase, the determinations of the critical Yukawa coupling value where the purely fermionic chiral transformation become a symmetry up to lattice artifacts; b) in the Nambu-Goldstone phase of the resulting critical theory, a stringent test of the actual generation of a fermion mass term of non-perturbative origin. A soft twisted fermion mass term is introduced to circumvent the problem of exceptional configurations, and observables are then calculated in the limit of vanishing twisted mass.