Boldon's offence was made public five months later
The Trinidad and Tobago sprinter tested positive for the banned stimulant ephesdrine at an event in California last April.
However, the violation was not revealed by officials from the International Assocation of Athletics Federations until 11 days ago.
Boldon escaped suspension because, under IAAF rules, the infraction is only punishable by a public warning.
"It has embarrassed me somewhat and I'm sure it has disappointed some of my fans.
"Let's be clear on what ephedrine is, however.
This is not a steroid and it's not a hormone. I maintain my stand against drugs in track and field and I welcome being tested as I have been for 10 years."
Cold remedy
Ephedrine can bolster performances during bursts of powerful effort. The drug has been linked to potentially fatal heart problems.
But Boldon said he only ingested the drug while taking a cold remedy because he was ill after a long trip to South Africa earlier in the year.
"Taking a cold medicine and it being found in my system is not a doping offence - a sentiment echoed by the IAAF in their release on this."
He added: "I think the rules need to be changed.
"Too often we see athletes being lumped into the 'doping offence' category for something like this when in fact they are guilty of trying to get themselves well.
"As a fan wrote to me, 'How can the world expect you to be almost super-human on the track and yet you can't even take the remedies us regular humans take if we get sick?'.'"
Boldon never found his form this season and finished fourth in the 100m at the World Championships in Edmonton last month.