Pharmacokinetics of fluorine contained in the Royale Saint-Yorre mineral water

The pharmacokinetics of oral fluoride supplied by one half liter of Royale Saint-Yorre water, which contains 8.50 mg fluoride per liter, were studied in ten healthy volunteers. Fluoride plasma kinetics and urinary excretion of fluoride were determined over 24 hours. After ingestion of one half liter Royale Saint Yorre mineral water, mean peak serum fluoride level was 159 +/- 22 micrograms/l. Time to peak serum level was 1 h (0.9 +/- 0.21 h) and area under the curve from 0 to 24 hours was 1,040 +/- 168 micrograms/l/h. Mean urinary fluoride was 2.57 +/- 0.4 mg (range 1.90 to 3.32 micrograms). The authors compared their findings with previously published data on fluoride pharmacokinetics after oral administration of an enteric-coated sodium fluoride tablet containing 11.35 mg elemental fluoride (12 healthy volunteers). Both peak serum level standardized for the dose of elemental fluoride and time to peak serum level were greater with the water than with the tablet. The authors cannot conclude as to which of the two types of fluoride exhibits the best bioavailability because their absorption coefficients have not been determined. This study demonstrates that Royale Saint Yorre mineral water is a valuable source of fluoride. Additional prospective studies are needed to determine whether it has therapeutic potential.