Sylvester Stallone has been charged with illegally taking a performance enhancing drug into Australia.The 'Rocky' star was not present when he received the charge of importing a banned substance in a Sydney court today. The case was adjourned until April 24 when the 60-year-old's legal representatives will be asked to enter a plea. Stallone and his entourage were stopped at Sydney airport on February 16 when they flew in to promote his latest film 'Rocky Balboa'. Members of the party were found to be carrying vials of muscle enhancing Human Growth Hormone which was seized by authorities. Human Growth Hormone can't be imported to Australia without a permit from the Therapeutic Goods Administration.The actor's hotel room and private jet were searched on February 19, before he was permitted to leave the country.The maximum penalty for illegally importing the growth hormone into Australia is a fine of $86,000 and five years in prison.The 'Rambo' star is unlikely to face the maximum penalty, but could receive a heavy fine.