the dug must dissolve in. an aqueous environment in order to be absorbed
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what. does the degree of ionisation depend on
pKa of the drug and local pH
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what is pKa
pH at which 50% of drug is ionised and 50% unionised
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What is absorption of weak acids facilitated by
by the pH of the stomach lumen
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when are bases absorbed
when they reach the small intestine
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where does the majority of absorption occur?
in the small intestine
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what kind of acids and bases are well absorbed
weak
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what factors affect gastro intestinal absorption
blood flow, pH, gastrointestinal motility ,the way a tablet is manufactured , physicochemical interactions, the. presence of transporters
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what. is oral and systemic availability
oral availability- the fraction of the drug that reaches the systemic circulation after oral injection - amount in systemic circulation/ amount administered . systemic availability is the fraction that reaches the systemic circulation after absorptio
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continued
amount in systemic circulation/ amount absorbed
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drugs administered orally, once absorbed can be inactivated bt what?
enzymes in the gut wall and liver before reaching the. systemic circulation and body tissues
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