Biricodar is primarily used in research settings to study multidrug resistance (MDR) in cancer cells. It functions as a potent inhibitor of P-glycoprotein, a protein that pumps chemotherapeutic drugs out of cancer cells, reducing their effectiveness. By blocking this protein, it helps researchers understand and potentially overcome resistance to anticancer drugs. Its application is significant in developing strategies to enhance the efficacy of chemotherapy in treating resistant cancers. Additionally, it serves as a tool in pharmacological studies to explore drug transport mechanisms and interactions within cellular systems.