The kinetics of salivary elimination of cyclophosphamide in man.

Abstract

The concentrations of cyclophosphamide in plasma and saliva were determined in seven patients following administration of single doses of cyclophosphamide during chemotherapy for lymphoma. 2 The saliva/plasma ratio was 0.77 +/- 0.24 (s.d.) and showed no time-dependence being rapidly established following intravenous and oral administration. 3 The T 1/2 of cyclophosphamide (8.38 +/- 2.25 h) determined from salivary measurements was not significantly different from that in plasma (8.24 +/- 2.60 h). It was not possible to estimate the apparent volume of distribution or total body clearance utilizing the salivary cyclophosphamide concentration without appropriate correction for the saliva/plasma concentration ratio. 4 The binding to the plasma protein of normal plasma of cyclophosphamide was 13.4 +/- 5.3%. The Scatchard plot for binding to bovine serum albumin indicates only weak binding to non-specific sites. 5 Salivary cyclophosphamide therefore indicates the concentration of the unbound fraction of plasma cyclophosphamide.