An inulin-like clearance based on the atomic absorbance of a copper cluster compound

Copper cluster ions which contain 14 copper atoms and 12 penicillamine ligands produce no indications of toxicity when injected intravenously in doses of 12 mg/kg (as the hydrated sodium salt). These ions pass freely through the Bowman's capsules and are eliminated with the urinary effluent. The blood plasma and blood serum kinetics of the process may be followed with selectivity and sensitivity using copper's flame atomic absorbance at 324.7 nm, and a first order rate law with a half life of approximately ten minutes is observed. Clearance obtained by this method is inulin-like. The copper cluster ion does not readily permeate the erythrocyte membrane, and its distribution immediately following intravenous injection appears to be essentially that of the plasma volume. Since serum or plasma preparation for atomic absorbance measurements is minimal, the method might have applications in rapid determinations of renal clearance.