CHIKV-IN-5 (Compound 26) is an inhibitor of CHIKV with an EC90 value of 0.45 μM. It suppresses the replication of CHIKV in the later stages of the viral life cycle by blocking the translation of structural proteins. CHIKV-IN-5 demonstrates high stability in vitro within mouse microsomes. In infected mice, it alleviates footpad swelling and reduces the spread of the virus to other tissues.

CHIKV-IN-5 demonstrates a significant reduction in viral titer in normal human dermal fibroblasts (NHDF) at a concentration of 10 μM, achieving a VTR of 8.7 log, and exhibits stability in vitro in mouse microsomes (MLM t1/2 of 74 min). It prevents CHIKV replication post-entry in NHDF cells after 2 hours of exposure at 10 μM. Additionally, pretreatment with CHIKV-IN-5 (10 μM for 1 hour) inhibits the synthesis of CHIKV structural proteins in infected NHDF cells without affecting viral transcription.

Administered at 80 mg/kg via intraperitoneal injection twice daily for 3 days, CHIKV-IN-5 alleviates footpad swelling in CHIKV-infected mice and significantly reduces viral spread to other tissues. Additionally, CHIKV-IN-5 demonstrates good metabolic stability in male C57BL/6 mice at doses ranging from 0.5 to 20 mg/kg through intraperitoneal, intravenous, oral, and subcutaneous routes.