ADME

ADME is an abbreviation in pharmacokinetics and pharmacology for Absorption, Distribution, Metabolism, and Excretion. These are the four main processes that describe the drug's movement within the body and its eventual removal. A fifth process, drug transport, is sometimes added to the acronym, making it ADME-T.

Pharmacokinetics

Absorption

Absorption is the process by which the drug enters systemic circulation in the body. It depends on factors like the route of administration, dosage form, and drug formulation. The absorption rate can be influenced by pH, blood flow, surface area for absorption, and the presence of transport proteins^[1].

Distribution

Distribution is the dispersion or dissemination of substances throughout the body. Once absorbed, the drug gets distributed through the body's tissues and fluids. The volume of distribution (Vd) indicates the extent of this process. Drug properties like size, solubility, and charge, along with body factors like blood flow and protein binding, influence distribution^[2].

Metabolism

Metabolism, or biotransformation, is the chemical alteration of the drug by the body. The liver primarily does this, though other tissues like the gut and kidneys also contribute. This process can form active metabolites (contributing to the drug's action), inactive metabolites, or toxic metabolites. Enzymes, most notably the Cytochrome P450 system, play a crucial role in this process^[3].

Excretion

Excretion is the removal of the substances from the body. Most drugs are excreted through the kidneys into the urine, but some drugs can also be removed via feces, lungs, sweat, breast milk, or saliva. This process usually follows metabolism, as it's easier for the body to excrete water-soluble metabolites^[4].

Transport

Transport refers to the movement of the drug and its metabolites between different parts of the body. It includes both passive diffusion and active transport, which utilizes transport proteins. This process is essential for the drug's absorption and distribution, and also for its removal from the body during excretion^[5].

ADME in Drug Development

Understanding ADME processes is essential in drug development. It helps in predicting the drug's behavior in the body, its effectiveness, and potential side effects. In preclinical studies, ADME helps in selecting the most promising drug candidates for further development^[6].

See also

• Pharmacokinetics
• Pharmacodynamics
• Drug metabolism
• Pharmacology
• Clinical trial

References

• 1 Shargel, L., & Yu, A. B. (2012). Applied biopharmaceutics & pharmacokinetics (7th ed.). New York: McGraw-Hill.
• 2 Rowland, M., & Tozer, T. N. (2011). Clinical pharmacokinetics/pharmacodynamics: Concepts and applications (4th ed.). Philadelphia, PA: Lippincott Williams & Wilkins.
• 3 Ritter, J. M., Lewis, L. D., Mant, T. G., & Ferro, A. (2012). A textbook of clinical pharmacology and therapeutics (5th ed.). London: Hodder Arnold.
• 4 Katzung, B. G., Masters, S. B., & Trevor, A. J. (2012). Basic and clinical pharmacology (12th ed.). New York: McGraw-Hill Medical.
• 5 Fromm, M. F. (2004). Importance of P-glycoprotein at blood–brain and blood–cerebrospinal fluid barriers. Journal of Clinical Psychopharmacology, 24(1), 13-25.
• 6 Rang, H. P., Dale, M. M., Ritter, J. M., & Flower, R. J. (2012). Rang & Dale's pharmacology (7th ed.). Edinburgh: Churchill Livingstone.