In reality, drug absorption and elimination operate concurrently from zero to F.A.T. (τ), while only elimination continues to operate until infinity. (Macheras P, Tsekouras AA. Columbus’ egg: Oral drugs are absorbed in finite
time. Eur J Pharm Sci. 2022 Sep 1;176:106265.
doi:
10.1016/j.ejps.2022.106265. Epub 2022 Jul 19. PMID: 35863551. )