The cost of ingredients raise if the competitors also buy this drug. You can check it in the ingredients tab, just click on the ingredient and look at the right panel.
Go to the Cures tab and and click on the cure you’re making - I am going to bet that the market is oversaturated (over 100%), which reduces the amount of money customers are willing to pay for the product (It will keep going down and down until saturation is below 100%), and the increase in the ingredient’s price is a direct result also (Since every company is probably buying the ingredient to make the same drug)
Solution: Stop making the drug altogether - Change the production line to a different cure that isn’t oversaturated, or expand it to upgrade the cure to the next tier.