Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Assessment 1.2
Drug Biotransformation
| Question | Answer |
|---|---|
| ADME | Absorption Distribution Metabolism-what we are covering in these notes Excretion |
| Biotransformation | Metabolism |
| xenobiotics | compounds foreign to the body such as drugs |
| xeno-foreign | |
| Enzymes are what carry out biotransformation | |
| Two ways drugs are eliminated from the body | through liver and intestine |
| excreted in urine and feces, which they don't change their chemical structure | |
| metabolized or biotransformed and then excreted, which the chemical structure is changed | |
| The major objective of drug biotransformation reactions in the body is to make nonpolar drugs more polar so that they may be more readily excreted! | |
| Biotransformation results in not only making a drug more soluble for excretion but also often produces a metabolite that is no longer capable of producing a therapeutic response. | metabolite-derivative of structure |
| Biotransformation occurs primarily in the liver,secondary is the gastrointestinal tract, and the last is in the skin and lungs. | goal of the liver is make it more polar and excrete, the liver doesn't know how to make it more less active |
| 1st Pass | biotransformation in the GI tract adds to that percentage even more such that the amount of an orally ingested drug actually reaching the systemic circulation is significantly reduced. |
| occurs in the intestine prior to absorption, the bulk of 1st pass metabolism happens in the liver after absorption | |
| Anything in the GI tract is considered to "outside of body", it has to be absorbed to be considered "inside the body" | |
| Portal Vein takes the material to the liver. | |
| Look at page 4 of notes | |
| Cytochrome P450 | Enzyme, it catalyzes (changes in the structure of the drug) |
| cyto-cell chrome-color | |
| isozymes-enzymes with different structures | |
| Cytochrome P450 & Drug Interactions | two types: induction and inhibition |
| Inhibition | competitive binding at an enzymes binding site(s), high affinity for an enzymes will slow the metabolism of any low affinity drug at that particular enzyme |
| Ex: 2 enzymes going to the liver competing for a CYP3A4, one enzyme will occupy the CYP3A4, other enzyme will want it (competitive inhibition) but won't get it, less enzymes and metabolism result will give more drug to body | |
| Induction | substance(a drug) stimulates the synthesis of the enzyme or reduce its degradation and the metabolic capacity of that isozyme is increased |
| more enzyme and metabolism result in less drug body | |
| ****** Always the number of enzymes is important, more or less drug********* | |
| Metabolism- absorption of drugm then excretes, not leaving it in the plasma | |
| Inducers-increase amount of enzymes and metabolism, less drug in plasma | |
| Inhibitors- drcrease amount of enzymes and metabolism, more drug in plasma | |
| Prodrugs | an inactive compound that is administered and then transformed into an active substance by either chemical or metabolic means |
| activated in various places- stomach, intestines, liver, blood, and inside cells activated in various ways- cleavage of groups, biotransformation, addition of phosphates. | |
| Examples- Sulindac inactive form taken then becomes active (Sulfide) in the liver. Want to have inactive form until liver because the active form (sulfide) irritates the GI tract. | |
| Biotransformation Reactions | Phase I and Phase II- Does NOT have to occur in this order |
| Phase I- look at page 13 of notes to distinguish reactions | functionalization reaction (adding OH, oxidizing a C, hoping to make more polar) loss of activity |
| make a compound more hydrophilic by introducing or exposing a polar functional group | |
| Phase II- look at page 15 of notes to distinguish reactions | biosynthesis reaction (stick something on it) covalent linkage between a functional group and a highly polar conjugate |
| make a compound more hydrophilic by covalently linking them to a polar compound | |
| Enterohepatic recirculation entero-intestine hepatic-liver | higher molecular weight conjugates formed w/ glucuronic acid are excreted in the bile& as a result, are subject to enzymatic cleavage by intestinal microflorea (bugs). This enzymatic cleavage leadas to the release&reabsorption of the parent compound |
| blood streatm to liver(inside) to intestine(outside of body) via bile duct- to excretion but bugs remove glucoronic and parent structure goes back into the intestine, then circulation | |
| Gluthathione(GSH) | tripeptide, found in most tissues (kidney and liver), unusual side chain of gamma |
| detoxificationof xenobiotics- conjugates on the way of the thiol group to make something that is active, less active | |
| APAP Metabolism- look at page 18 of notes | at high levels tylenol is toxic to the liver |
| higher levels of NAPQI (reacts with free electrons which is very dangerous in the body), this can deplete cellular stores of gluthathione |
Created by:
lisagoette
Popular Chemistry sets