Effect of peptides on neutralization of enoxaparin in vivo in rats. Rats were cannulated in the jugular and femoral veins. Enoxaparin was injected through the jugular vein, and 3 minutes later the peptide was injected via the jugular vein. Blood was collected from the femoral vein; 0.1 mL was collected at each time point. Plasma was prepared from each tube, and the anti–Factor Xa assay was performed. The zero time point represents anti–Factor Xa activity in the assay before administration of enoxaparin. The A450 is inversely proportional to the enoxaparin concentration. A450 of 0.4 is equivalent to 1 U/mL anti–Factor Xa activity. The events at the arrows are indicated in the box insert. The data shown are limited to those 4 peptides that have been tested at both the 1 mg and 0.5 mg/300 g dosages.
