Drugs are developed in distinct phases. Usually, the drug discovery and
development process can be divided into these stages: select a disease, identify a target,
find a lead compound, quantify drug-target interactions, determine solubility,
pharmacokinetics and toxicity, improve the lead compound, find the best way to deliver the
drug to the patient, manufacture the drug, apply to the FDA to do investigational studies, do
the clinical studies, apply to the FDA for drug approval, and do post-registration studies.
The solubility, pharmacokinetics and toxicity are determined in GLP studies. Similar
compounds are tested in the lab and by computer modeling, so structure-activity
relationships (SARs) can be developed. Eventually, a new chemical entity (NCE) or
investigational new drug (IND) is selected for further evaluation. The optimum method for
drug delivery is selected. A manufacturing process is developed and documented according
to cGMP. Potential targets include membrane bound receptors (such as GPCRs, tyrosine
kinases and intracellular nuclear receptors). Agonists bind to receptors and mimic the
action of the endogenous ligand. Antagonists bind to receptors and block the binding and
subsequent action of the endogenous ligand. Enzymes, DNA, protein transporters, ion
channels and pumps are other potential targets.
Keywords: New chemical entity, NCE, investigational new drug, IND,
quantitative structure-activity relationships, QSAR, agonist, antagonist, cGMP,
GLP.
