Enantioseparation of D- and L- isomers of Chiral Drugs for Improving their Bioavailability: Some Techniques Including Micellization with Gemini Surfactants

  The enantiopure drugs are essential for disease treatment as the human body is amazingly chiral selective. Nearly 50% of drugs are chiral but the pharmacological activity resides with only one isomer, termed as eutomer, whereas the other isomer which is inactive or less potent metabolizes by a different way in the body. This toxic isomer in a racemic drug causes side-effects, genetic disorder or may cause even death if taken in high dosage. Therefore, role of stereochemistry in drug action getting more and more attention of medical practice and one should be good knowledge to make decisions regarding while using single enantiomer of any drug. Most of the drugs used in psychiatric practice are currently available in mixture of enantiomers. For some therapeutics, one particular isomer of chiral drug give better pharmacological results with respect to the target organ, bioavailability in body plasma, low toxicity etc., as compared to racemic mixture of that drug. This article explains the chirality of drugs, the stereochemistry of isomers of chiral drugs, emphasizes the difference in the potential biological and pharmacologic differences between the two enantiomers of a drug, and highlights the novel technique to increase the in-vivo solubility of particularly one isomer of drug, so that the bioavailability of eutomer can be enhanced. This can be done by used of surfactants, which encapsulate the enantiomers of drugs at different extend by micellization.