When a drug is 50% protein bound. it means that:

50% of the dose is at work

The percentage of drug NOT protein bound is the amount of drug that is free to exert its effect on the bodys issues. A. C. and D are incorrect because protein binding has nothing to do with the destruction of protein. drug excretion. or protein in the diet. Note that the concept of 50% bound literally means that 50% is BOUND or connected to protein. This means that the remaining 50% is available.