Oseltamivir phosphate

China [CN]

Oseltamivir phosphate is a prodrug that is metabolized to the active neuraminidase inhibitor oseltamivir carboxylate, blocking the release of influenza A and B viruses from infected host cells. It is used for the treatment (within 48 hours of symptom onset) and prophylaxis of influenza.

Key properties:

• CAS Number: 204255-11-0 (phosphate salt)

• Molecular Formula: C₁₆H₂₈N₂O₄ · H₃PO₄

• Molecular Weight: 410.40 g/mol

• Appearance: White to off-white crystalline powder

• Brand Names: Tamiflu®

Clinical highlights:

• Orally bioavailable (≈75%)

• Reduces duration of influenza symptoms by approximately 1 day

• Prophylactic efficacy ≈70-90%

• Must be taken within 48 hours of symptom onset for treatment benefit

• Resistance reported via H275Y mutation in influenza A(H1N1)