Pharmacokinetics of the major metabolites of D-penicillamine in patients with rheumatoid arthritis.

The pharmacokinetic disposition of D-penicillamine and its major metabolites, penicillamine cysteine disulfide ( PSSC ) and penicillamine disulfide ( PSSP ) has been studied in eight patients with rheumatoid arthritis. Plasma concentrations of D-penicillamine, PSSP and PSSC displayed similar characteristics in terms of times to maximum concentrations and biphasic elimination from plasma. Initial t1/2 (alpha) phase ranged from 0.86 to 4.41 h for parent drug and 0.81 to 4.41 h for metabolites. Final t1/2 (beta phase) ranged from 3.4 to 9.45 h for D-penicillamine and 5.62 to 21.7 h for the metabolites. Total drug and metabolites detected in urine accounted for 12.0 to 48.7% of oral drug.