ABSTRACT
After passing a series of hurdles the candidate drug eventually reaches the clinic. Here it is subject to further detailed investigation, often referred to in terms of various phases (see Panel 14.9). From this stage onwards the chemist has less and less influence on what is done, provided the drug moves forward smoothly. If problems arise, then a commercial decision will usually be made depending on the nature of the difficulty, ranging all the way from going back to the bench to modify the structure to abandoning the drug altogether.
