Direct Analysis of Triclosan Deposition on Hydroxyapatite by Spectroscopic Methods

In order to develop enhanced methods for the delivery and retention of active agents on oral surfaces, it is necessary to quantify the amount of deposition (uptake) on a surface as well as characterize the nature of the interaction between the active and the surface. The conventional in vitro methodology utilizes hydroxyapatite (HAP) disks as model hard tissue substrates. Active agents, either in neat solutions or in dentifrice formulas, are incubated with saliva-coated HAP (scHAP) disks, washed, and then subject to solvent extraction and subsequent quantification by high-performance liquid chromatography (HPLC). This process has limitations. Objectives: The overall objective of this study is to develop rapid analytical methods for direct quantification of active delivery on oral surface models. Based on our objective the aim of this study was to validate the use of Near-Infrared (Near-IR) and Ultraviolet (UV) spectroscopy to analyze Triclosan delivery on scHAP. Methods: ScHAP disks treated with Triclosan liquid dentifrice solutions and commercial dentifrice slurries were analyzed for Triclosan deposition by both Near-IR and UV spectroscopy. After analysis, the Triclosan on the scHAP disk was extracted and quantified by HPLC. Results from the three methods were compared. Results: Both Near-IR and UV spectroscopy can be used to quantify Triclosan deposition on scHAP. There was a strong correlation between the spectroscopic analysis and the conventional method (r²= 0.9446). Conclusion: Near-IR and UV spectroscopy can be used routinely as analytical tools and will provide an accurate and rapid method of measuring the efficacy of active delivery systems in oral care products.