> I mean what is the fundamental difference between a cooking recipe and the recipe for a pharmaceutical.

The effort required for validating them. Pharmaceutical compounds can reach into the hundreds of millions of dollars just for the clinical trials and certifications of production steps, and on top of that comes the cost to failed attempts which are rolled into the pricing of products that do make the cut.

A cooking recipe however, unless you're dealing with stuff like fugu fish, will not kill or injure those who replicate and eat it, and there's no regulatory hurdles to pass.