Overview on Chirality and Applications of Stereo-selective Dissolution testing in the Formulation and Development Work

The importance of chirality is considered in various areas such as purchasing of active pharmaceutical ingredient,selection of adjuvants in dosage form development,in vitro dissolution studies,stability studies,in vitro / in vivo correlation (IVIVC),dossier preparation for technology transfer,ANDA/NDA applications and in scale up and post approval changes (SUPAC). The use of chiral selective dissolution testing is recommended for certain drugs that exist in racemic form in order assess the performance of a product,both in vitro and in vivo.An extension of the Biopharmaceutics Classification System (BCS) is suggested for drugs that undergo chiral conversion after permeation through gastrointestinal wall,taking into account that the amount of active form of the drug reaching the receptor site is more important. It is suggested that the shelf life for chiral drugs shall be determined by considering the amount of degradation of the active form (R or S) of the drug. This paper also gives a brief overview of work done on chirality from the viewpoint of formulation of dosage forms. 16