Former world number one Maria Sharapova has revealed she failed a drugs test at the Australian Open. The 28 year old Russian star tested positive for meldonium, a substance, she has been taking since 2006 for health issues. The International Tennis Federation said, Sharapova, a five time Grand Slam champion, is provisionally suspended from March 12th pending further action. Sharapova, who lives in Florida, provided the anti-doping sample in question on January 26th, the day she lost to Serena Williams in the Australian Open quarter finals.