[Rat in vitro plasma-binding percentage determination of sinomenine hydrochloride by using microdialysis method and ultrafiltration].

To assess feasibility of plasma protein-binding percentage by using microdialysis method. Sinomenine hydrochloride was selected as model drug. The in vitro rat plasma protein-binding percentage of three kinds of concentration was determinated by using microdialysis sampling tool and HPLC-UV. At the same time the classical study method, such as ultrafiltration method, was also used to determinate the protein-binding percentage to compare the difference between the two methods. The in vitro rat plasma protein-binding percentage of sinomenine hydrochloride using microdialysis method was about 26% and kept relative stable at the concentration range. There was no significant difference between the two methods. The results shows that the binding percentage is relative low. Microdialysis method is a new method for the study of protein-binding degree.