[Pharmacokinetic Studies After Oral Application of Radioactively Labelled D-penicillamine]

14C-labelled D-penicillamine was given orally to healthy test subjects in different dosages. The time course of serum activity was followed up to 5 weeks and the urinary activity was measured for 4 days. The obtained results equalled the sum of active substance and its 14C-labelled biotransformation products. The maximal serum concentration appeared about 2 hours after ingestion, the obtained concentrations being proportional to the dosis. Thereafter the concentration declined first relatively fast, then increasingly slower. From the 4th day after ingestion the half time of elimination was 8 days. The urinary excretion was dose dependent; the urinary concentration increasing with higher dosage. The later long half time of elimination corresponded to disappearance from the blood of the portion of the drug firmly getting attached to collagen and elastic tissue structures. The several weeks latency of onset of antirheumatic effect may be due to the fact that the portion of the drug getting attached to connective tissue accumulates slowly.