Drug ADME (Absorption, Distribution, Metabolism and Excretion) process

Drug ADME (Absorption, Distribution, Metabolism and Excretion) process
Pharmacokinetics is the study generally done with the drug before it comes to the market. This study is very helpful in knowing the working of the drug in our body through ADME process. ADME process involves absorption, distribution, metabolism and excretion. Normally, it takes 15 years to market the drug. In order to reduce the duration of the drug discovery and prevent the life of animals, the in silico method was discovered. ADME process is carried out for the oral drugs. There are many routes of administration of the drug but when the drug is taken orally, a part of the drug gets absorbed in mouth and then passes to the stomach. The cell membrane of the stomach is lipid bilayer and the outer layer is hydrophilic and sometimes hydrophobic. Therefore, the drug must be hydrophobic in order to get solubilized in the lipid bilayer; if it is hydrophilic it cannot be solubilized in the lipid bilayer; and if it is more hydrophobic, it will enter into the brain and this phenomenon is known as blood brain barrier. From the stomach, the drug passes into the intestine; the pH of the stomach varies in each part of the stomach; hence, while entering into the stomach, the drug tends be in acidic or nonionic form in order to get soluble; further, the drug passes into the small intestine, where it becomes basic to get soluble in the small intestine. From there, the drug passes into the systemic circulation for the distribution of drug to the other tissues of the body. In the blood circulation, there are plasma bound and unbound proteins; the drug must bind with the unbound protein in order to bind with the specific tissue, but in our blood 97% is plasma bound protein. There are six cytochromes that help in metabolism and these cytochromes must function properly in the metabolism, if they fail to function properly, it will result in toxicity. Metabolism happens in two phases, such as phase 1 and phase 2. In phase 1 the drug gets formulated to be more hydrophilic and in phase 2 (in liver) the polar groups get added to the drug to make it more hydrophilic. Cytochrome is required in the process of metabolism to break the parent drug into metabolite. After all this journey, the drug gets excreted through urine or sweat.
How to cite this article:
Veronica Grite. Drug ADME (Absorption, Distribution, Metabolism and Excretion) process. BioLim O-Media. 20 , 6-11. 1(3).
Available from: http://archive.biolim.org/omedia/read/BOMA0036.