## **Core Concept**
The question tests the understanding of pharmacokinetic properties of various Nonsteroidal Anti-Inflammatory Drugs (NSAIDs), specifically their ability to penetrate tissues and concentrate in synovial fluid, which is relevant in the treatment of inflammatory conditions like arthritis.

## **Why the Correct Answer is Right**
Diclofenac is known for its good tissue penetrability. It has a high degree of lipophilicity, which allows it to easily cross cell membranes and achieve therapeutic concentrations in various tissues, including synovial fluid. This property is particularly beneficial in treating conditions like rheumatoid arthritis, where inflammation of the synovial membrane is a key feature. Diclofenac's ability to concentrate in synovial fluid helps in reducing inflammation and pain effectively.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While some NSAIDs have good bioavailability, their tissue penetrability and concentration in synovial fluid may not be as favorable as diclofenac.
- **Option B:** This option might have pharmacokinetic properties that are not as optimal for tissue penetration and synovial fluid concentration compared to diclofenac.
- **Option C:** Similarly, this NSAID might not have the same level of lipophilicity or pharmacokinetic profile that allows for high concentration in synovial fluid.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that diclofenac is often used in the management of osteoarthritis and rheumatoid arthritis due to its potent anti-inflammatory effects and ability to achieve high concentrations in synovial fluid, making it effective for treating joint inflammation.

## **Correct Answer:** . Diclofenac