The pharmacokinetics of intramuscular gold sodium thiomalate in normal volunteers

Four normal male volunteers participated in a study designed to examine the disposition of gold given intramuscularly as gold sodium thiomalate. Blood samples were collected for 32 days following the administration of 10 mg of gold sodium thiomalate. Plasma gold concentrations were determined by atomic absorption spectrometry. A triphasic decay pattern in plasma gold concentrations was observed. Terminal log-linear phases corresponded to a mean disposition half-life of 25 days. Apparent total body clearance of gold was 7.0 +/- 0.6 ml kg-1 day-1 and the apparent volume of distribution was 0.26 +/- 0.051 kg-1. These pharmacokinetic data are in contrast to previous data from other investigators who have reported half-lives of approximately 5 days. Data from the current study provide a sound rationale for the currently used empiric dosing regimens.