liberation absorption distribution metabolism elimination

liberation Liberation is the process in which a pharmaceutical substance is released from the formulation it is delivered in. This must occur before the drug can be absorbed into the body.

Absorption Absorption is the process in which a pharmaceutical substance enters the blood circulation in the body

amount of drug absorbed / drug dose

Distribution Distribution is the process in which a pharmaceutical substance is dispersed through the fluids and tissues in the body

metabolism Metabolism is the process in which a pharmaceutical substance is transformed into other substances, called metabolites, in the body

excretion Excretion is the process in which a pharmaceutical substance is removed from the body. In rare cases, some drugs may never be completely excreted from the body. They then irreversibly accumulate in the tissues.

1. passive diffusion 2. facilitated diffusion 3. active transport 4. endocytosis and exocytosis

the drug moves from an area region of high concentration to one of lower con- centration Passive diffusion does not involve a carrier, is not saturable, and shows low structural specificity.

the diffusion of solutes through transport proteins in the plasma membrane does not require energy, can be saturated, and may be inhibited by compounds that compete for the carrier.

This mode of drug entry also involves specific carrier proteins that span the membrane active trans- port is energy-dependent, driven by the hydrolysis of adenos- ine triphosphate (ATP). It is capable of moving drugs against a concentration gradient, from a region of low drug concentration to one of higher concentration

This type of absorption is used to transport drugs of an exceptionally large size across the cell membrane. Endocytosis involves engulfment of a drug by the cell membrane and transport into the cell by pinching off the drug-filled vesicle. Endocytosis is a cellular process in which substances are brought into the cell. Exocytosis is a form of active transport and bulk transport in which a cell transports molecules out of the cell.

activation inhibition complexation neutralization

By binding to the target site if the drug molecule stimu­lates the process or selectively accelerates the process.

On the target site a drug molecule exhibiting its action by inhibiting the process or selectively deaccelerating the pro­ cess.

On the target site, the drug molecule exhibiting its action by making a complex, thereby making it inactive by sequesterization

The drug molecule binding to the target site and neutralizing the action of the existing molecule directly through a chemical reaction or physical interaction

reduction, oxidation, or hydrolysis reactions. These reactions serve to convert lipophilic drugs into more polar molecules by adding or exposing a polar functional group

This phase consists of conjugation reactions. If the metabolite from phase I is sufficiently polar, it can be excreted by the kidneys.

1. transmembrane ligand-gated ion channels 2. transmembrane G protein- coupled receptors 3. enzyme- linked receptors 4. intracellular receptors

The extracellular portion of ligand-gated ion channels contains the drug-binding site. This site regulates the opening of the pore through which ions can flow across cell membranes. The chan- nel is usually closed until the receptor is activated by an ago- nist, which opens the channel for a few milliseconds. functions: neurotranbsmission and muscle contraction

These cell surface receptors act like an inbox for messages in the form of light energy, peptides, lipids, sugars, and proteins. Such messages inform cells about the presence or absence of life-sustaining light or nutrients in their environment, or they convey information sent by other cells.

This family of receptors undergoes conformational changes when activated by a ligand, resulting in increased intracellular enzyme activity. phosphorylation- substantially modify the structure of the tar- get protein, thereby acting as a molecular switch

it acts as a messanger and pathways. the DGP will replace into GTP. Here comes the glycogenolysis which means breakdown of stored sugar and to be distributed to the liver. it lso has 3 subunits which are the 1. muscarinic the M1- M5 or the acetylcholine (rrelax) 2. nicotinic- the neurotransmitter (contract) 3. adrenergic- beta 1 and beta 2 (relax)

it is the opening of different channels pr ions but it depends on the concentration gradient to have its effect. it also has a corelation witrh influx which means retains and the fflux which means nilalabas.

Its process is the phosphorylation- adiition of phosphate group into an ion or molecule To replcae the structure of the binding site then it will release an effect

describes the actions of a drug on the body.

1. activation - by binding to the target site if the drug molecule stimulates the process or selectively accelerates the process 2. inhibition- drug molecule exhibiting its action by inhibiting the process or selectively deaccelarating the process 3. complexation- on the target site, the drug molecule exhibiting its action by making a complex, thereby making it inactive by sequesterization. 4. neutralization- the drug molecule binding to the target site and neutralizing the action od the existing molecule directly through a chemical reaction or physical interaction

what bosy does to drug. it involevees movement of drug and includes the study of absorption, distribution, metabolism, and excretion of drugs.

1. glomerular filtration - Glomerular filtration is the first step in making urine. It is the process that your kidneys use to filter excess fluid and waste products out of the blood into the urine collecting tubules of the kidney, so they may be eliminated from your body. 2. proximal tubular secretion - Tubular secretion is especially important for drugs that are highly plasma protein bound, because these drugs are not excreted effectively by glomerular filtration. 3. distal tubular reabsorption- a passive process whereby drugs are reabsorbed into the systemic circulation from the lumen of the distal tubules

The chemical nature of a drug strongly influences its ability to cross cell membranes. Lipophilic drugs readily move across most bio- logic membranes. These drugs dissolve in the lipid membranes and penetrate the entire cell surface.

First-pass hepatic metabolism- the drug is rapidly metabolized in the liver or gut wall during this initial passage, the amount of unchanged drug entering the systemic circulation is decreased. Solubility of the drug- For a drug to be readily absorbed, it must be largely lipophilic, yet have some solubility in aque- ous solutions. This is one reason why many drugs are either weak acids or weak bases. Chemical instability- Some drugs, such as penicillin G, are unstable in the pH of gastric contents. Others, such as insulin, are destroyed in the GI tract by degradative enzymes. Nature of the drug formulation- Drug absorption may be altered by factors unrelated to the chemistry of the drug.