The Italian world number one tested positive for traces of the steroid clostebol last year.
He was exonerated but the World Anti-Doping Agency appealed and is seeking a ban of up to two years, with a hearing scheduled at the Court of Arbitration for Sport (CAS) for April.
"I mean, what happened, happened," he said after taming Alexander Zverev 6-3, 7-6(4), 6-3 to successfully defend his Australian Open title.
"As I always say, I keep playing like this because I have a clear mind on what happened. If I knew if I would be guilty, I would not play like this, and that's it.
"I still believe every time it came out in a very positive way, and I still believe it's going to be that case.
"At the moment I'm not thinking about this," he added. "Of course, you have your moments of certain days where you feel like I wish I would not have this problem.
"In the other way, I'm always looking forward to go on court."
Sinner has said the drug entered his system when his physio used a spray containing it to treat a cut, then provided massage and sports therapy to the player.
The CAS hearing is set to occur before the next Grand Slam at Roland Garros, and Sinner said he was unsure how it might affect his preparations.
"Tough to say. I mean, I'm not thinking at the moment like this," he said.
"I just came off an amazing run again here. I want to enjoy this moment, to be honest.
"Then it's the hearing. We know now the dates, and that's it. I mean, I want to enjoy this one now."
Mastering all surfaces
Sinner has now his sights on mastering clay and grass courts to make himself a complete player.
Sinner has reached the semi-finals at the French Open and Wimbledon in the last two seasons but he said he hoped to assert his authority on clay and grass this year.
"You have to be a complete player, not only on one surface but on also the other two," Sinner told reporters.
"I believe last year wasn't a bad season at all on clay and on grass. I can do better, yes, but let's see. I mean, these are questions that I can answer by playing."
Sinner, who has won 37 of his last 38 matches on hardcourts, said he would dedicate his time and energy to going far in the other Grand Slams.
"I'm still young and I have time to adjust, especially on grasscourts, because I've never played the juniors. It was new when I arrived on the tour," Sinner added.
"It's exactly that what I like; the difficulties trying to understand where I can improve. Hopefully I can show that when the season arrives."