The absorption of drugs via the oral route is a subject of intense and continuous investigation in the pharmaceutical industry since good bioavailability implies that the drug is able to reach the systemic circulation by mouth.” – Pang, Drug Metab Dispos. 2003; 31: 1507

The word “absorbed” can carry a negative connotation, as seen in “self-absorbed,” but absorption of drugs has changed oral drug delivery for the better. Knowledge of drug absorption has led to modifications in the creation and administration of oral drugs.

Drug absorption is defined as a drug’s movement to the bloodstream from its administration site. When oral drugs are only partially absorbed, bioavailability is reduced. Absorption occurs through either passive diffusion or cell-mediated transport.

Knowledge of drug absorption has led to changes in how oral drugs are made. For example, the knowledge that certain drugs irritate the stomach or dissolve completely in the stomach before making it to the intestines shows the need for enteric coating. Two examples of enteric-coated drugs are omeprazole and aspirin, according to Lippincott’s Illustrated Review: Pharmacology. Specially fabricated controlled-release drugs use knowledge of drug absorption to delay or extend absorption.

Knowledge of drug absorption has led to changes in the administration of oral drugs, too. Knowing how different drugs interact with food affects when and how drugs are taken. Grapefruit juice, for example, increases bioavailability by inhibiting presystemic drug transport; this increased bioavailability negatively impacts the efficacy of cyclosporin but not that of pravastatin. Learning about drug absorption has changed oral drug creation and administration processes for the better. Orbis’s OptimµmTM platform, which is used to create extended-release oral drugs, is a great example of that.