The kinetics of substituted AT III concentrate in the congenital AT III deficient patients.

AT III concentrate (Behringwerke) was administered to approximate the activity up to 80-120% on 4 congenital AT III deficient patients. AT III antigen was assayed by single radial immunodiff usion and activity was by S-2238 as heparin cofactor activity.From the determined values of antigen and activity of infused AT III, regression line of time course was obtained for each case by computor analysis using the two compartment open model. Biological half life (T 1/2) was 72.3±35.8hrs for antigen and 75.6±18.0hrs for activity. Distribution volume (Vd) for antigen was 7.2±2.43L. Initial half disappearance time was about 24hrs. Mean maximal increase of AT III level was 0.27±0.04(mg/dl)/U/kg for antigen and 0.82±0.20%/U/kg for activity.Based on the data of single dose experiments, the simulation curves of multiple administrations were calculated on the different intervals of infusion, and the reasonable steady state of concentration was considered to be achieved on the administration of 24hr- and 12hr-interval.One of the deficient patients was received AT III concentrate every 24hrs for 3 days, and the simulation curve of 24hr-interval infusion was well correlated with the actually determined value, and the steady state of concentration was achieved in 120hrs after starting of the infusion.