C. Mircioiu and S.A. Borisova

Biopharmacy Department, “Carol Davila" University of Medicine and Pharmacy, Bucharest Romania.

Abstract:

Based on theoretical considerations concerning parallel between platelets and erythrocytes aggregation and sedimentation of only great aggregates it was checked the hypothesis that platelets antiaggregant clopidogrel decrease the sedimentation of erythrocytes.

The erythrocyte sedimentation was determined at normal volunteers and patients with rheumatic or coronary artery disease. 0.8 ml blood was collected on 0.1 ml 1% EDTA and then was added 25, 50, 75, 100 and 200 µl solution of 20 µg/ml Clopidogrel. EDTA was used instead of citrate due to the limited solubility of Clopidogrel in the presence of citrate. The final concentrations were in the range 1 - 8 µg/ml for Clopidogrel.

A global analysis put in evidence that the cluster of sedimentation curves shifted toward smaller values, the effect of clopidogrel being the decreasing of sedimentation.

The effect on the average height of sediment column was linear in concentration at all examined times (15, 30 and 60 minutes). The effect was linear in the 1 - 4 mg/l clopidogrel concentration. Saturation of the effect appeared to be between 4 and 8 mg/l. Regression lines were more or less parallel, the effect being less dependent on measuring time.

If it is to accept the largely spread idea that only one of clopidogrel's metabolites is active as antiaggregant, the results suggest hypothesis of existence of a local metabolism at blood cells level.

Keywords: Platelet Aggregation, Erythrocytes Aggregation, ESR, Clopidogrel and Metrics on Sedimentation Curves.