Studies on the hydrolysis and absorption of monofluorophosphate ions.

Monofluorophosphate (MFP), usually sodium-MFP, Na2PO3F, has become widely used in dentifrices and has been suggested for the treatment of osteoporosis. Its PO3F-- ions are hydrolyzed to F ions and orthophosphate by phosphatases. Experiments on rats showed no such splitting in the stomach, very rapid hydrolysis in the small intestine and the liver, and slower hydrolysis in the blood. In both rats and humans, no evidence of direct absorption of PO3F-- ions into the blood was found. The findings explain the low acute toxicity and the absence of gastric irritation of MFP.