Salivary elimination of cyclophosphamide in man

A total of 25 plasma and saliva samples were obtained from three hospital inpatients upon intravenous short-time infusion of cyclophosphamide; total doses infused ranged from 5.3 to 13.3 mg/kg. Despite interindividual variations, a correlation was found for plasma-to-saliva ratio of 1.61 +/- 0.53 (S.D.). Our Saliva-to-plasma ratio of 0.62 is in agreement with a recently reported ratio of 0.77. The ratio stayed constant throughout the observation period (0.5 to 8.4 hours), indicating that the noninvasive method of saliva sampling seems to be a useful approach in cyclophosphamide drug concentration monitoring in patients.