Definition A route of administration in pharmacology and toxicology is the path by which a drug, fluid, poison, or other substance is taken into the body.
Routes of administration are generally classified by the location at which the substance is applied. Common examples include oral and intravenous administration.
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Definition First Pass Effect:When a drug is administered orally, the drug is absorbed by the mesenteric veins. These veins drain into the portal vein which flows into the hepatic sinusoids.
Half-life: The amount of time required to eliminate 50% of the drug in the body. The half-life can be determined from a semilogy graph of the plasma concentration versus time or it can be calculated from the elimination constant.
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Pharmacokinetics, sometimes abbreviated as PK that is a branch of pharmacology dedicated to determining the fate of substances administered externally to a living organism via specific route to the drug characteristics.
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PharmacokineticA process which formed from:
Liberation- the process of release of a drug from the pharmaceutical formulation Absorption - the process of a substance entering the blood circulation.
Distribution - the dispersion or dissemination of substances throughout the fluids and tissues of the body.
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PharmacokineticMetabolization (or biotransformation, or
inactivation) – the recognition by the organism that a foreign substance is present and the irreversible transformation of parent compounds into daughter metabolites.
Excretion - the removal of the substances from the body. In rare cases, some drugs irreversibly accumulate in body tissue
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Routes of Administration/Enteral1. Oral route (p.o.):EasyUsually safeEconomical
Routes of Administration/Parenteral1. Intravenous (IV):Permits titration of dosageLowest intra-individual variabilityMost rapid response (emergencies)Most suitable for irritating substances and large volumes