A comparison of fluoride bioavailability from a sustained-release NaF preparation (Neosten) and other fluoride preparations

Twelve normal subjects completed a crossover study with sustained-release sodium fluoride (Neosten, 11.3 mg F), monofluorophosphate (MFP, 10 mg F), and plain sodium fluoride (P-NaF, 11.3 mg F). After each preparation was given with 400 mg calcium, serum fluoride (F(ser)) was measured for 24 hours, and pharmacokinetic data were calculated. Fluoride absorption in the Neosten group, as measured by change in the area under the curve (ΔAUC) of F(ser), was less than 33% of that in the MFP and P-NaF treated groups. Both peak F(ser) (C(max)) and peak-basal variation in the Neosten group were 25% that found in the other groups, t( 1/2 ) was nearly twofold greater after Neosten. MFP and P-NaF showed greater bioavailability than Neosten and much higher C(max) that exceeded the toxic threshold of F(ser) (190 ng/ml). These findings could explain the ineffectiveness of MFP and P-NaF observed in recent clinical trials. (C) 2000 the American College of Clinical Pharmacology.