Argatroban Inhibition of Fibrin Clot-Bound Thrombin
| Clot Age (h) . | [CaCl2] (mmol/L) . | [Albumin] (mg/mL) . | Maximum Activity (mOD/min) . | IC50 (μmol/L) . | Maximum Inhibition (% control) . |
|---|---|---|---|---|---|
| 0.5 | 0 | 0 | 2.9 ± 0.1 | 2.2 ± 0.3 | 89 |
| 3.0 | 0 | 0 | 3.7 ± 0.2 | 1.8 ± 0.2 | 88 |
| 6.0 | 0 | 0 | 3.1 ± 0.0 | 1.6 ± 0.3 | 88 |
| 3.0 | 1 | 0 | 3.4 ± 0.3 | 1.6 ± 0.9 | 76 |
| 3.0 | 2 | 0 | 2.8 ± 0.4 | 4.6 ± 0.9 | 80 |
| 3.0 | 5 | 0 | 3.3 ± 0.0 | 2.2 ± 1.3 | 73 |
| 3.0 | 0 | 3 | 4.1 ± 0.6 | 1.7 ± 0.2 | 90 |
| 3.0 | 2 | 3 | 3.9 ± 1.3 | 1.2 ± 0.2 | 91 |
| 3.0 | 2 | 3 | 4.3 ± 0.1 | 0.8 ± 0.1 | 89 |
| Clot Age (h) . | [CaCl2] (mmol/L) . | [Albumin] (mg/mL) . | Maximum Activity (mOD/min) . | IC50 (μmol/L) . | Maximum Inhibition (% control) . |
|---|---|---|---|---|---|
| 0.5 | 0 | 0 | 2.9 ± 0.1 | 2.2 ± 0.3 | 89 |
| 3.0 | 0 | 0 | 3.7 ± 0.2 | 1.8 ± 0.2 | 88 |
| 6.0 | 0 | 0 | 3.1 ± 0.0 | 1.6 ± 0.3 | 88 |
| 3.0 | 1 | 0 | 3.4 ± 0.3 | 1.6 ± 0.9 | 76 |
| 3.0 | 2 | 0 | 2.8 ± 0.4 | 4.6 ± 0.9 | 80 |
| 3.0 | 5 | 0 | 3.3 ± 0.0 | 2.2 ± 1.3 | 73 |
| 3.0 | 0 | 3 | 4.1 ± 0.6 | 1.7 ± 0.2 | 90 |
| 3.0 | 2 | 3 | 3.9 ± 1.3 | 1.2 ± 0.2 | 91 |
| 3.0 | 2 | 3 | 4.3 ± 0.1 | 0.8 ± 0.1 | 89 |
Thrombin activity bound to aged fibrin clots, formed from purified components, was determined in the clot permeation assay, as described in the text and the legend to Fig 1. Results are expressed here as the maximum activity, ie, the mean and standard deviation of results obtained in triplicate samples, in the absence of argatroban. The IC50 parameters and their standard deviation were determined by fitting the data obtained as a function of argatroban concentration to equation 1 or 2 (last entry only), in each case by nonlinear regression analysis. The maximum inhibition was obtained from the thrombin activity determined in the presence of excess argatroban and is expressed as a percentage of the maximum (ie, control) activity.