A drug which is entry inhibitor ?
**Core Concept**
The entry inhibitor is a class of antiretroviral drugs used in the treatment of HIV/AIDS that prevents the virus from entering the host cells. This class of drugs targets the gp120 protein on the surface of the HIV virus, blocking its attachment to the CD4 receptors on the host cells.
**Why the Correct Answer is Right**
Entry inhibitors, such as maraviroc, block the attachment of the HIV virus to the CD4 receptors on the host cells by binding to the gp120 protein on the surface of the virus. This prevents the virus from entering the host cells and replicating. The gp120 protein is a critical component of the HIV virus that facilitates its attachment to the CD4 receptors, and blocking this interaction prevents viral entry.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specifically target the entry of the HIV virus into host cells. Protease inhibitors, such as atazanavir, target the protease enzyme of the HIV virus, which is involved in the maturation of the viral particles.
* **Option B:** This option is incorrect because nucleoside reverse transcriptase inhibitors (NRTIs), such as tenofovir, target the reverse transcriptase enzyme of the HIV virus, which is involved in the replication of the viral genome.
* **Option D:** This option is incorrect because integrase inhibitors, such as dolutegravir, target the integrase enzyme of the HIV virus, which is involved in the integration of the viral genome into the host cell genome.
**Clinical Pearl / High-Yield Fact**
Entry inhibitors, such as maraviroc, are particularly useful in treating HIV/AIDS in patients with certain genetic variations in the CCR5 receptor, which is the primary co-receptor used by HIV for entry into host cells.
**Correct Answer:** C.