Antibiotics is a product which is made from Sugar, Ammonia and Oxygen. It can only be used to make Medical Supplies II with Medical Supplies. It produces Carbon Dioxide as a byproduct which can be vented away or used for Graphite. It can only be produced in a Fermentation Tank. Like other ingredients for Medical Supplies, this material doesn't have many uses. Thus can very easily be connected directly to the Assembler for Medical Supplies II.
Below are all the recipes, which contain this item. Note, that some of them may be locked behind Research, and not immediately available in your game.