What is ADME?
ADME is widely used as an acronym for absorption, distribution, metabolism and excretion in pharmacology and pharmacokinetics. It is used to describe a pharmaceutical compound’s disposition within an organism. The four terms that come together form the abbreviation ADME. It stands for the influence of the levels of drug and kinetics of the exposure of the drug to the tissues in the body. This, in turn, influences the pharmacological activity and performance of the drug compound. Sometimes toxicity or/and liberation is taken into consideration producing ADMET, LADMET, and LADME.
What is studied under the ADME process?
ADME studies are conducted to determine whether a drug candidate is viable by answering the following questions:
· Absorption – How quickly a drug is absorbed and in what quantity?
· Distribution – Where within the body is the drug distributed?
· Metabolism – How quickly does the drug get metabolized? What kind of metabolite it forms and whether it is toxic or active?
· Elimination – How quickly and in what process is the drug eliminated or excreted from the body?
ADME assays often involve research on toxicity which studies whether the drug’s effect on the body is toxic for the system or any organ of the body.
What has been the contribution of ADME studies on drug development and discovery?
When it comes to studying the ADME pharmacokinetics and pharmacology is totally indebted to the technology of the process because of how crucial it is in determining the safety and efficacy of a drug. As per estimates, about 50% of drug compounds fail for not being qualified as efficient. And, 40% of them fail due to toxicity. Often drugs can cause toxicity in combination with other drugs, and the ADME assays have been instrumental in identifying these cases. Drugs like soruvidine, phenylpropanolamine hydrochloride, and mibefradil have been withdrawn from the market because of drug-drug interactions or toxicity. The ADME process has been able to establish the importance of ADME/Tox studies apart from the general pharmacological properties in ensuring the success of a drug. Hence, the ADME studies are now conducted in the early stages of the drug discovery process itself.
In which stage is the ADME process conducted?
After selecting a drug as a potential candidate for clinical use, in vivo and in vitro studies are carried out to help the drug developer make the go-no-go call. It is then moved into programs like preclinical and clinical studies. Studying the ADME properties allows developers to understand the probability of a drug getting selected for clinical use in the very initial stages of medical research. Drug discovery and development is an expensive process, and long-term investment on research the effects of a drug compound can be a costly affair. ADME analysis has made the process more cost-effective by providing drug developers with initial data at the earliest stages of medical research. This makes them better informed to take decisions whether or not to further invest on the research of a drug candidate. However, throughout the process, one needs to adhere to the strict guideline of regulatory authorities like FDA.