Aprotinin plasma concentrations

After IV injection rapid distribution of aprotinin occurs into the total extracellular space leading to a rapid initial decrease in plasma concentration. It has a plasma half-life of 2.5 hours. After a single IV dose 25-40% is excreted in the urine over 48 hours. It is accumulated primarily in the kidney (it is actively absorbed by the proximal tubules). 

Fig. 5. Plasma concentration of intact 125I-cystatin C( ), 51Cr-EDTA ( ) and 131I-aprotinin(Y) relative to the initial plasma concentration after intravenous injection in 12 rats. Error bars show 1 SEM, when larger than the symbols. Aprotinin is a 6.5-kDa microprotein with a pi of 10.5.

Aprotinin is not effective after oral administration, but is administered intravenously as a loading dose followed by a continuous infusion. Its activity is expressed as kallikrein inactivation units (KIU). The conventional (Munich) dose regimen consists of an initial 2 x 10 KIU bolus, a similar initial dose to prime the bypass machine, and then 0.5 x 10 KIU/ hour by continuous infusion thereafter. The half-life of aprotinin is about 2 hours. Plasma concentrations of 125 KlU/ml are necessary to inhibit plasmin, but a... 

Fig. 5.5 Concentration-time profiles of glucose in plasma after large intestinal administration of insulin in the presence of various protease inhibitors. Key (O) control (A) 20 mM Na glycocho-late (NaCC) (A) 10 mM bacitracin ( ) 20 mM bacitracin ( ) lOmgmL" aprotinin ( ) 20 mM...

Kemppainen, R. J., T. P. Clark, and M. E. Peterson. 1994. Preservative effect of aprotinin on canine plasma immunoreactive adrenocorticotrophic concentration. Domestic Animal Endocrinology 11 355-362. 

Figure 6.10 Effect of streptokinase (SK) on fibrinogen concentration and platelet aggregation induced by ADP in platelet-rich plasma. Platelets were incubated with streptokinase for 1 minute prior to the addition of ADP, lfimo L and aggregation monitored by light transmission. Samples for fibrinogen were collected in aprotinin to prevent continued lysis. The fibrinogenolytic and proaggregatory effects of streptokinase were concentration dependent and were inhibited by aprotinin and e-aminocaproic acid (e-ACA)...

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