Ineffectiveness of intramuscularly injected Factor 8 concentrate in two hemophilic patients.

PROPHYLACTIC therapy of hemophilia is handicapped by the short half-life of factor VIII in the circulation (eight to fifteen hours). However, even 1 per cent of the normal level probably confers some protection against spontaneous bleeding. The hope that intramuscular injection would be followed by continuous, slow release into the circulation prompted this clinical trial using the high-potency concentrate now routinely produced in blood banks.1 Reports on preparations for intramuscular injection appeared in 1945 for human beings and in 1957 for dogs, but the assay methods in the former, and the large injection volumes in the latter, make the results . . .