Lead compound is a chemical compound that has pharmacological or biological activity and whose chemical structure is used as a starting point for chemical modifications in order to improve potency, selectivity, or pharmacokinetic parameters.
Definition of Structure-activity relationships (SAR):
** It is the traditional practices of medicinal chemistry which try to modify the effect or the potency (i.e. activity) of bioactive chemical compounds by modifying their chemical structure.
** Medical chemists use the chemical techniques of synthesis to insert new chemical groups into the biomedical compound and test the modifications in their biological effect. This enables the identification and determination of the chemical groups responsible fo evoking a target biological effect in the organism.
** This method was later refined to build mathematical relationships between a chemical structure and its biological activity, known as quantitative Structureactivity relationships QSAR.