How about a medical vending machine in public spaces, however only those with chemistry and medical access can set them, they can set prices, and it starts off unstocked, needing to be manually stocked?
The money would either go to the medical department's funds with a portion to the person who set up the sale, or just the person who set up the sale, depending on how we want to do things.
That way, the station only ends up with direct access to chems that the people who stock the machines themselves see to be safe and worth the effort, with consequences possible given a misjudgement.