Determination of dexamethasone in saliva

We conducted experiments to demonstrate that the determination of dexamethasone in saliva is a valuable tool to assess dexamethasone concentrations in the body after administration of this synthetic corticosteroid. After extraction of saliva, a RIA involving highly specific commercially available antibodies was established and evaluated. This RIA was easy to conduct, reliable, and sensitive enough to measure dexamethasone until approximately 24 h after oral administration of 1 mg per 70 kg of body weight. On the morning after the administration, the mean concentration in saliva was 540 pmol/L. Over a large range (10(3)-10(6) pmol/L), plasma concentrations correlated very well with salivary concentrations; plasma contained six times more dexamethasone than saliva.