Table 2.

Concentration of FIX measured in joint synovial fluid at 2 h after IV delivery of FIX concentrates

FIX concentrate	IV dose (IU/kg)	Plasma FIX concentration (ng/mL)	Synovial fluid lavage FIX concentration* (ng/mL)
rFIX	250	3734	25
N9-GP	250	5747	35
rFIX in plasma:rFIX in synovial fluid lavage (diluted)*			149:1
N9-GP in plasma:N9-GP in synovial fluid lavage (diluted)*			164:1
N9-GP:rFIX in plasma			1.54
N9-GP:rFIX in synovial fluid			1.4

^*Lavage of the joint results in an estimated ∼10-fold dilution of the synovial fluid.