Probably the same issue as with the Medicine Pack: Unless you happen to have the ingredients, the recipe is not displayed and you have no idea how to make it. For the Medicine Pack, you will probably stumble over it eventually, but for the Medicine Vial?
It is still at least bad design. You build a Sick Bay or Medical Clinic and an Aphothecary, and then what? Please display the recipes.
Steps to Reproduce
Build all documented stuff for treating dupes, find that the game does not tell you the ingredients you need unless you stumbled over them by accident earlier.
This issue has been fixed in either a future version or updated in a previous version.