Oral absorption and secretion of drugs.

Monitoring salivary misonidazole in man: a possible alternative to plasma monitoring

“…Similar findings have been reported by others (Kostlin & Rauch, 1957;Mason & Chisholm, 1975 & Speirs, 1976;Speirs, 1977). The various secretions show some differences in composition, and differences between gingival fluid and the glandular secretions are particularly marked (Mason & Chisholm, 1975).…”

“…Estimation of salivary drug concentrations has recently proved useful for a variety of drugs (see reviews by Speirs, 1977;Horning et al, 1977) including methotrexate (Steele et al, 1978). We have therefore investigated the feasibility of monitoring the salivary concentration of MIS in 10 patients with neoplastic disease under treatment.…”

Factors determining the passage of drugs from blood into saliva.

“…Though we have studied gingival fluid in greatest detail, only small volumes are readily obtained from dentate subjects and none is available from the edentulous. In addition the volume may be affected by poor oral hygiene or administration of drugs such as phenytoin (Speirs, 1977;Anavekar et al, 1978). Parotid saliva however can be obtained without difficulty in reasonably large volumes and contrary to our earlier thoughts, it is probably the best mixed salivary component for inferring the plasma levels of drugs, and in particular the unbound fraction (Anavekar et al, 1978).…”

Saliva concentrations of isosorbide dinitrate, isosorbide 2‐mononitrate and isosorbide 5‐mononitrate.

“…For several drugs, there is good evidence that measurement of their concentrations in saliva can be a convenient alternative to determination of those in plasma, and is useful both in monitoring therapeutic drug levels and in pharmacokinetic studies (Danhof & Breimer, 1978;Homing etal., 1977;Speirs, 1977). The present study compares and correlates the plasma and saliva concentrations of isosorbide dinitrate (ISDN), isosorbide 5-mononitrate (5-ISMN) and isosorbide 2-mononitrate (2-ISMN) obtained after administration of single oral doses of 40 mg of sustained-release ISDN to human subjects.…”

“…For a drug that enters the secretory cells of the salivary gland by passive diffusion, saliva could be regarded as an ultrafiltrate of plasma, and it has been shown for a number of drugs that the concentration in saliva reflects the fraction of drug that is unbound to plasma proteins (Danhof & Breimer, 1978;Horning et al, 1977;Laufen et al, 1983;Speirs, 1977). Such appears to be the case for 5-ISMN, since this compound is fairly hydrophilic and essentially is not bound to plasma proteins (Chasseaud, 1983); concentrations of 5-ISMN found in the plasma and saliva were similar (Figure 1).…”