Blood levels of ditazole and inhibition of platelet aggregation in man.

5 healthy volunteers (3 males, 2 females, aged 22-35 years) were given 600 mg ditazole (Ageroplas) every 12 h (9.00 a.m. and 9.00 p.m.) for 10 days. Venous blood was collected from all volunteers at 9.00 and 11.00 a.m. on days 0, 3, 5, 7 and 10. The threshold concentrations of adrenaline inducing two distinct waves of platelet aggregation (Born's method) within 3 min were determined each time. Blood levels of ditazole were measured by a gas-chromatographic technique using a nitrogen-phosphorus selective detector. The average blood levels of the drug ranged between 0.84 and 1.30 microgram/ml at 9.00 a.m., and between 1.93 and 2.85 microgram/ml at 11.00 a.m. Inhibition of platelet aggregation (expressed by a grading system in arbitrary units) ranged between 1.6 and 2.0 at 9.00 a.m. and between 2.0 and 2.4 at 11.00 a.m. The fluctuations of blood levels and platelet aggregation inhibitory activity of ditazole observed during the study period were virtually the same. It is suggested that the treatment schedule used in the present study results in blood levels of ditazole sufficient to reveal any consistent alteration of platelet function in normal subjects.