Oral delivery and clearance of antiplaque agents from Triclosan-containing dentifrices

Oral delivery and clearance of Triclosan and zinc were studied following use of three commercially available Triclosan-containing toothpastes. One paste contained 0.3 per cent Triclosan and 2 per cent PVM-MA copolymer, one contained 0.3 per cent Triclosan and 5 per cent sodium pyrophosphate and the third contained 0.3 per cent Triclosan and 0.75 per cent zinc citrate trihydrate. Each gave similar total oral retention of Triclosan (37 per cent-46 per cent of the dose). However, clinically important product differences were observed in the salivary clearance of Triclosan and in Triclosan delivery to plaque. The Triclosan/zinc paste delivered more Triclosan to oral reservoirs (as measured by the area under the salivary clearance curve) than either the Triclosan/PVM-MA or the Triclosan/pyrophosphate paste (p < 0.001). The Triclosan/zinc paste produced higher Triclosan levels in plaque than the Triclosan/PVM-MA paste (109 micrograms/g versus 78 micrograms/g, p < 0.05). Zinc was effectively delivered to oral surfaces by the Triclosan/zinc paste, and was cleared more slowly than Triclosan (single-reservoir t1/2 = 50 min). After use of the Triclosan/zinc paste the zinc level in plaque was 153 micrograms/g, a seven-fold increase over the control. These results demonstrate that good delivery of Triclosan requires a highly optimised formulation. Furthermore, they suggest that the superior clinical effects of the Triclosan/zinc paste are due to a combination of superior delivery of Triclosan to oral sites of action together with effective delivery of a second, complementary antiplaque agent, zinc.