A new low molecular weight heparin fragment (PK 10169): in vitro and in vivo studies.

The depolymerized heparin fragment PK 10169 was compared with conventional mucosal sodium heparin. The inhibition of factors Xa and IXa by heparin and by PK 10169 was similar on a weight base whilst the inhibition of thrombin by PK 10169 was at least 5 times weaker than by heparin. Subcutaneous injection of PK 10169 was not followed by prolongation of the thrombin time. The APTT was considerably less prolonged after PK than after heparin. Platelet reaction was increased by heparin but was not influenced by PK 10169. In vitro the euglobulin lysis time (ELT) was shortened after addition of heparin to plasma but not after addition of PK 10169. After injection, however, there was an equal shortening of the ELT by both substances. Advantages of PK 10169 over heparin are therefore a weaker anticoagulant effect and the missing influence on platelet functions.