What is the penalty for single dose controlled substance?

This would likely be a 5th Degree Controlled Substance Possession crime. It's punishable by up to 5 years in prison and a $10,000 fine. You wouldn't see nearly that level of consequences. What you should be thinking more about is whether you're going to end up with a permanent felony conviction. You should hire an experienced lawyer to defend you. We can challenge the charges and the evidence against you while at the same time negotiating with the prosecutor for a deal that keeps this thing off of your record.