Final answer:
The student's question concerns the plasma protein binding and absorption of diclofenac, which are high, and its mechanism of action, which is via the inhibition of cyclooxygenase (COX), not through an increase in endorphins.
Step-by-step explanation:
The student's question is about the drug diclofenac, specifically its plasma protein binding, absorption percentage, and mechanism of action.
Option A suggests that the plasma protein binding of diclofenac is 99%, which is quite high. This means that the drug binds very well to the proteins in the blood, which can influence its distribution, efficacy, and elimination.
Option B states that the absorption percentage is 90%, indicating that a large proportion of the drug is absorbed into the systemic circulation after oral administration. High absorption can be associated with good bioavailability.
Regarding Option C, diclofenac's mechanism of action is not through the increase in endorphins but rather it functions as a nonsteroidal anti-inflammatory drug (NSAID), primarily by inhibiting the enzyme cyclooxygenase (COX), which is involved in the synthesis of prostaglandins, contributing to inflammation, pain, and fever.