[Pharmacokinetics of gold after administration of aurokeratinate (author's transl)]

Aurokeratinate (Auro-Detoxin) was administered intramuscularly to patients with chronic rheumatoid arthritis, using two different dosage schedules and measuring serum gold concentration. (1) Using slowly rising doses (as generally practised) the gold level gradually rose to 3.2 microgram/ml after four weeks (before the ninth injection), without reaching cumulation equilibrium. Elimination from serum occurred during this phase, with a half-life of 3-5 days. When treatment was continued at about 25 mg gold twice weekly, the cumulation equilibrium was reached with a minimal value at 3.5 microgram/ml and a maximal one of 6 microgram/ml, elimination half-life then being increased to nine days. During the subsequent maintenance treatment with 65 mg gold once a month the serum-gold concentration fell to about 1 microgram/ml, maximal values being about 6 microgram/ml, with an elimination half-life of 11 days. (2) With a constant dose of about 25 mg gold twice weekly, cumulation equilibrium was reached after two weeks (3.4 microgram/ml before the fifth injection), while on 50 mg gold every 14 days as maintenance dose the serum concentration was between 2 microgram/ml minimally and 6 microgram/ml maximally. At the modified dosage the drug was well tolerated.