Determination of plasma protein binding rate of arctiin and arctigenin with ultrafiltration Correlation study on in vivo pharmacokinetics and anti-oxidation of Guhong Injection in cerebral ischemia reperfusion injury model of rats Determination of plasma protein binding rate of bufalin Determination of plasma protein binding rate of methyl protodioscin with ultrafiltration Determination of plasma protein binding rate of bufalin Determination and comparison of plasma protein binding rate of alkaloids from seed of Strychnou nux-vomica