The Russian tested positive for banned substance meldonium, which she has been taking since 2006 for health reasons. Meldonium has been on the banned list since 1 January 2016.
World No7 Sharapova admitted full responsibility for the failed test but insisted she was unaware that the substance was now on the prohibited list, having previously consumed it legally.
“I received a letter from [world governing body] the ITF [International Tennis Federation] saying that I failed a drugs test at the Australian Open,” said Sharapova.
“For the past 10 years I have been given medicine called mildronate by my family doctor and a few days ago after I received the ITF letter I found out that it also has another name of meldonium which I did not know.
“It is very important for you to understand that for 10 years this medicine was not on WADA’S [World Anti-Doping Agency] banned list and I had legally been taking the medicine for the past 10 years.
“But on 1 January the rules had changed and meldonium became a prohibited substance which I had not known.”
Sharapova, whose last match was her Australian Open quarter-final defeat to Serena Williams in January, remains one of only 10 women to complete a career grand slam.
While she has is, as yet, unaware of the sanctions she will face, the 2004 Wimbledon champion hopes this episode will not spell the end of her time in the sport.
“I made a huge mistake,” she added. “I know I face consequences and I didn’t want to end my career this way. I hope I will be given the chance to play this game again.”