Lithium carbonate as a potential pharmacological vehicle: intravenous kinetics of single-dose administration in healthy subjects.
OBJECTIVE
We have been developing lithium carbonate solution as a vehicle for delivery of uric acid in a research setting. We wished to determine the pharmacokinetics of a single systemic administration of 500 mg lithium carbonate (13.5 mmol free Li(+)) in healthy subjects.


METHODS
Ten healthy subjects received 500 ml of a 0.1% lithium carbonate and 4% dextrose solution intravenously over 1 h. Serum lithium concentrations were determined at baseline, 15, 30, 45, 60, 75, and 90 min, and 2, 3, 7, 24, and 48 h after the start of infusion for kinetic analysis.


RESULTS
Administration led to a time-dependent increase in plasma concentration, followed by a rapid decay of serum lithium concentration. Kinetic analysis showed that the pattern best fit a two-compartment model, with rapid extravascular distribution, an elimination phase half-life of 7.8+/-1.7 h, and clearance of 5.3+/-1.1 l/h.


CONCLUSIONS
In healthy subjects, lithium half-life is shorter and clearance is higher than suggested by previous reports in other groups. Administration of 500 ml 0.1% lithium carbonate and 4% dextrose over 1 h is safe, well tolerated, and possibly a suitable vehicle for other agents such as uric acid.
Waring
W Stephen
WS
Clinical Pharmacology Unit and Research Centre, The University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK. s.waring@ed.ac.uk
Webb
David J
DJ
Maxwell
Simon R J
SR
D000293:Adolescent; D000328:Adult; D016503:Drug Delivery Systems; D005260:Female; D006207:Half-Life; D006801:Humans; D007262:Infusions, Intravenous; D016651:Lithium Carbonate / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D008297:Male; D012995:Solubility; D014527:Uric Acid / Q000008:administration & dosage*
D014527:Uric Acid; D016651:Lithium Carbonate