Which excipients are listed for Avonex (interferon beta-1a) 30 micrograms/0.5 ml solution for injection?

Avonex (interferon beta-1a) 30 micrograms/0.5 ml solution for injection contains sodium acetate trihydrate, glacial acetic acid, arginine hydrochloride, polysorbate 20 and water for injections as excipients.