Summary
The limitations of currently used in vitro assays of heparin have demonstrated the
need for an in vivo method suitable for routine use.
The in vivo method which is described in this paper uses, for each heparin preparation, four
groups of five mice which are injected intravenously with heparin according to a “2
and 2 dose assay” procedure. The method is relatively rapid, requiring 3 to 4 hours
to test five heparin preparations against a standard preparation of heparin. Levels
of accuracy and precision acceptable for the requirements of the British Pharmacopoeia
are obtained by combining the results of 3 to 4 assays of a heparin preparation.
The similarity of results obtained the in vivo method and the in vitro method of the British Pharmacopoeia for heparin preparations
of lung and mucosal origin validates this in vivo method and, conversely, demonstrates that the in vitro method of the British Pharmacopoeia
gives a reliable estimation of the in vivo activity of heparin.
