Question

The state of health and functioning of the liver is often assessed with dye-tracer techniques. The dye used most frequently is bromosulfophthalein (abbreviated BSP). With normal function liver, the dye will be removed from circulation after it is conjugated with cysteine or glutathione (which happens in the liver) following a first order kinetics k=0.5 hr-1 at 37°C. The usual clinical procedure is to have a single injection to the blood and then to measure the amount remaining in the liver after a certain period of time. Liver function is assessed by comparing the experimental value with the range of normal values. Assuming the flow of the dye from the blood stream to liver is donor control and of linear relationship (k12= 1 hr-1).

1)Identify the engineering principles needed to solve this problem ( 5 pts).

2)Develop the differential equations to describe the amount of drug in each compartment ( the blood stream and the liver ) (5 pts)

3)Clearly state your assumptions (5 pts)

4)Find the amount of the dye in the liver 1 hours after an injection of 10 mg of the dye into the blood stream ( 5 pts)

5)If the amount of the dye in the liver is determined to be 4.0 mg after 1 hour of injection. What can potentially go wrong with this patient? ( 5pts)

Answer 1

1.Disposition of bromophthalein (BSP) and was compared in control, phenobarbital, or alpha-naphthylisothiocyanate-(ANIT)-treated rats, and in the isolated perfused rat liver preparation. After dye administration, BSP was found to have a more rapid early plasma disappearance rate, a more rapid appearance in the liver, and a greater rate of biliary excretion both in vivo and in the isolated perfused liver, than that of BSP. In considering these observations, it is concluded that hepatic uptake as well as biliary excretion of BSP is faster than that of BSP.

And this is the principle behind the problem