In Vivo: Fostamatinib (R788) is highly bioavailable, and rapidly absorbed in Louvain rats. R406 following a single oral dose of R788 10 mg/kg or 20 mg/kg: AUC0-16 hrs= 10618 ng*h/mL and 30650 ng*h/mL respectively; Cmax=2600 ng/mL and 6500 ng/mL respectively (observed at 1 hour); t1/2=4.2 hours. The prodrug was not detected in plasma suggesting R788 is completely converted to R406.