Overview of Hit to Lead: The Medicinal Chemist's Role from HTS Retest to Lead Optimization Hand Off

A medicinal chemist combines organic synthesis expertise and the ability to optimize chemistry structure-activity relationships (SAR) based on relevant biomedical information so as to achieve project goals. The ability to optimize chemistry SAR consists of both the easier to explain logical stepwise structural modification that is often described by quantitative structure-activity relationships (QSAR) and the more difficult to explain exercise of high-order pattern recognition. Optimizing SAR is full of traps for the unwary. What are the pros and cons of various types of screens Should one believe the screening data How does one optimize against multiple sometimes conflicting properties What types of compounds are worth screening How does one judge the quality of a screening hit Very importantly, drug discovery is a team exercise in which the medicinal chemist plays a key facilitating role. Given good interpersonal skills, the medicinal chemist's training is broad enough to enable cooperative interactions across the whole discovery team. Chemistry pattern recognition is the unique skill that the medicinal chemist contributes to drug discovery. The ability to relate chemistry structure to biological activity and to change chemistry structure so as to change a variety of biomedical parameters in a desired direction leads to the successful “drug hunter.”