What Is Fragment-Based Drug Discovery

Section 1 discussed, somewhat theoretically, fragment linking and fragment growing, and acknowledged that these are but two ends of a continuum. The examples below demonstrate how these simple categories apply in practice, as well as how they break down. 

However, before proceeding further, it is useful to ask exactly how to define FBDD. The challenge lies in the fact that more than 400 approved drugs could be defined as fragments using the Rule of 3 described above, yet few if any were discovered using fragment-based approaches. 

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