| A method based on the Concentration Derivative Product (CDP) is proposed to analyze the thermodynamics of Drug-Receptor interactions. CDP is defined as the product of the fractional inhibition f and it’s concentration derivative. Assuming Michaelis-Menten kinetics, it is shown that for a number of drug-receptor systems (HIV protease, ACE, HMG-CoA, Opioid receptor inhibitors, etc.) f max = 0.333, irrespective of the nature of bonding interactions and Ki. The CDP max = [4 / ( 27 Ki ) ], and gives a measure of the drug potency directly. CDP also gives thermodynamic information about the ratio of the gradients of the inhibitor chemical potential in the free and bound states. |
