Pharmacokinetics of Iodine and Fluoride following Application of an Anticaries Varnish in Adults

Abstract

Researchers have suggested that combining topical fluoride with an antiseptic to reduce cariogenic bacteria may be more effective than fluoride application alone in preventing dental caries. In previous studies, povidone iodine (PVP-I), a widely used bactericidal antiseptic, and sodium fluoride (NaF), used to foster remineralization of enamel, were applied sequentially topically and shown to be safe and effective. The study aim was to characterize the kinetics of iodine and fluoride following topical application of a single combination PVP-I and NaF anticaries varnish in healthy adults. Sixteen participants (aged 23 to 57 y) participated in a pharmacokinetics study following the application of 0.4 mL varnish containing 10% (w/v) PVP-I and 5% (w/v) NaF. Serum and urine samples were collected at various time points over 24 h following application of varnish. Iodine and fluoride concentrations were analyzed, and for each time point, baseline concentrations were subtracted from observed values. Following varnish application, 2 of 16 participants had nearly undetectable baseline-corrected iodine and fluoride levels, suggesting minimal absorption, lack of release of iodine and fluoride from the varnish, or inconsistent dosing. The average peak concentrations were 57 ± 33 ng/mL iodine and 60 ± 34 ng/mL (0.060 ± 0.034 ppm) fluoride and occurred within 3 h of application. The average elimination half-life was 5.5 ± 1.4 h and 3.1 ± 1.6 h for iodine and fluoride, respectively. Renal clearance of iodine and fluoride was similar to literature values. No adverse events related to the study varnish were observed by the investigative team or reported by the participants. In this study, serum fluoride and iodine transiently increased but were within normal range 24 h after application of the varnish. This study has shown that the combination of PVP-I and NaF in a proposed anticaries varnish was well tolerated. Knowledge Transfer Statement: This clinical study demonstrated that a dental varnish combining 10% (w/v) povidone iodine and 5% (w/v) sodium fluoride is well tolerated. Serum fluoride and iodine transiently increased but were within normal range after 24 h. Further studies should be conducted to assess the efficacy of a combination in preventing dental caries, especially in high-risk populations.

Keywords: clinical study; dental; dental caries prevention and control; dental pharmaceutical preparations; healthy volunteers.

Conflict of interest statement

P. Milgrom is a director of Advantage Silver Dental Arrest, LLC. The authors declare no other potential conflicts of interest with respect to the authorship and/or publication of this article.

Figures

Figure 1.

Kinetics of iodine following application of the povidone iodine and sodium fluoride varnish. (A) Observed serum iodine concentrations (n = 16) and (B) baseline-corrected iodine concentrations with extrapolated values (open symbol) (n = 16) versus time. The 24-h timepoint was not used in the pharmacokinetic analyses.

Figure 2.

Kinetics of fluoride following application of the povidone iodine and sodium fluoride varnish. (A) Observed serum fluoride concentrations (n = 16) and (B) baseline-corrected fluoride concentrations with extrapolated values (open symbols) (n = 14) versus time. Baseline-corrected concentrations that resulted in concentrations at the limit of detection for multiple time points (i.e., 10 ng/mL for fluoride) were excluded.

Figure 3.

Correlation of 24-h urinary recovery of iodine and total serum iodine AUC0-24 h (A), 24-h urinary recovery of fluoride and total serum fluoride AUC0-24 h (B), and urinary recovery of iodine and fluoride over 24 h following application of the povidone iodine and sodium fluoride varnish (C). AUC, area under the curve.