[Comparison of the fluoride bioavailability from two oral preparations of monofluorophosphate disodium in combination with various calcium salts].

We studied, in twelve healthy volunteers, the pharmacokinetics of inorganic fluoride and calcium variations in serum and urine, parathormone variations in serum after administration of two oral preparations containing 100 mg of disodium monofluorophosphate (13.2 mg F as element) with different calcium salts (500 mg Ca as element). Fluoride was estimated in serum and urine with an ion specific electrode. The fluoride bioavailability from two preparations is identical with an areas under the curve corresponding to 61.05 and 62.53 mumols.l-1 h (after deduction of physiological fluoride concentrations) and urinary fluoride excretion after 72 hours corresponding to 266.6 and 246.1 mumols. The plasma peak appearance is rapid (one hour) and similar. The significant increase of urinary Ca-Creat ratio (70 to 100%) is identical four hours after drug administration. In the same way, a significant and early decrease of intact PTH in serum, measured with chemiluminometric method, was observed from two drugs. From these observations we may conclude that the two preparations are biologically equivalent.