Implications of basic pharmacology in the therapy with esters of nandrolone.

Experiments in rats have shown that esters of nandrolone injected intramuscularly, are absorbed from the depot according to the kinetics of a first-order reaction. The nature of the fatty acid chain in the ester determines the half-life of the compound in the depot. Once released from the depot, the ester is rapidly hydrolyzed by the esterases in the plasma. As a result, free nandrolone is the pharmacologically active agent whereas its availability to the target organs depends on the half-life time of the ester in the depot. It has been demonstrated that various androgenic target organs respond in a different manner to the changes in the concentration of nandrolone occurring during the period of resorption of the ester. This might explain the dissociation of anabolic from androgenic effects observed with esters of nandrolone. Knowing that the half-life for nandrolone decanoate in man is similar to that in rats, theoretical considerations are given with a number of dosing schemes.