Ames National Laboratory and Colgate-Palmolive are collaborating to improve the stability of stannous fluoride used in toothpaste.
The organizations are investigating the potential of nuclear magnetic resonance (NMR) to address the current challenges posed by stannous fluoride, a compound made of tin and fluoride (SnF2) and one of the active ingredients approved by the U.S. Food and Drug Administration for use in toothpaste under the Anticaries OTC Monograph.
The compound’s antimicrobial quality depends on the tin maintaining a +2 oxidation state, referred to as Sn(II). Researchers said the challenge is that when an aqueous tin fluoride solution is exposed to air, the tin ions slowly oxidize over time. It loses additional electrons and transforms into Sn(IV). However, it is difficult to determine how quickly the Sn(II) transforms into Sn(IV) because of the small amount of fluoride that is present.
Researchers said that dynamic nuclear polarization enhances the capabilities of NMR, allowing them to collect data on the small amounts of stannous fluoride in a variety of commercially available toothpastes. The data will give them a greater understanding of the molecular activity in toothpaste, including how ingredients interact with one another.
The Ames Lab and Colgate-Palmolive will continue their partnership to further investigate this issue and develop improvements.