The problem is even more complicated than the author presents. Much of the chemistry that happens within the body happens within cells. Serum levels are a poor

The problem is even more complicated than the author presents. Much of the chemistry that happens within the body happens within cells. Serum levels are a poor proxy for absorption into organ, tissue, and ultimately cell types. In fact, the problem is even more complex: the spatial organization of a cells within a tissue is heterogeneous; thus we can’t even reliably predict how well a drug will reach a particular cell type since it depends on the specific cell location. This is a reason why cancer is so difficult to treat: cancer cells often barricade themselves behind other cells and the tissue stroma, making it difficult to get a drug at a high enough concentration to kill the cancer cell. Biology is fiendishly complex and empirical. One regularly sees Silicon Valley types come along and propose to ‘disrupt’ the field using the latest fad from the field of computer science, only to slink away years later having been humbled by biology. The current fad is AI, which despite having added some extraordinary tools to the biologist’s tool chest, will also not live up to its hype.