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9 Cards in this Set
- Front
- Back
What are the big four elements of concern in pharmacokinetics?
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Absorption, Distribution, Metabolism/biotransformation, Elimination
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What is Fick's Law? What does it relate?
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Fick's law predicts the movement of a substance across a memberane:
Flux (mocecules/time) = (diff. in conc'n.) * Area * Permeability / thickness |
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Do membrane characteristics play a role in absorption?
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You bet. Each has it's on characteristic pH, blood flow, etc.
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Regurgitate the Henderson-Hasselbach equation.
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pKa - pH = log (Protonated / Unprotonated )
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What happens when a solution's pH matches the pKa of a substance?
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Equal parts protonated and unprotonated exist - a 50/50% mix.
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Why is it that weak acid drugs absorb well through the stomach?
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With so many excess protons, weak acids will easily protonate/neutralize in the stomach and cross the lipophilic capillary membrane into circulation.
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How are lipid-soluble compounds typically excreted?
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Lipid soluble compounds are typically metabolized to a charged, more water-soluble species.
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Why do drugs on a protein carrier stay in circulation longer?
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Drug-Carrier interactions avoid kidney filtration, thereby staying circulation
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How can altering the pH of urine affect drug elimination?
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Similarly to the stomach, drugs mass more readily through kidney membranes w/out charges. For weak acids, a more basic urine solution will strip them of their proton, keeping them in urine.
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