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16 Cards in this Set
- Front
- Back
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when a drug is bound to a protein |
it is unable to produce a effect it will not be digested |
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once a drug molecule is delivered to the plasma, most drugs will |
reversibly bind to plasm proteins found there serum is the most abundant w/ net negative charge acidic and hydrophobic drugs bind w/ high affinity |
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the protein bound form of the drug |
lowers the plasma concentration of free drug and therefore affects the drug absorption profile the bound form is unavailable for tissue distribution the bound form needs to dissociate from the protein in order to be metabolized or excreted |
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protein binding therefore affects |
pro-drug activation and drug duration |
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human serum albumin properties |
585 amino acid polypeptide multiple binding site plasma con of 40mg/ml (600 mM) binding affected by intra and inter(variability) |
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causes changes in drug binding |
diseases genetic make up |
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the number of binding sites |
exceeds the number of drug molecules |
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the association constant Ka can be determined by measuring the |
fraction of the protein bound to the drug and the amount of free drug in the plasma |
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equilibrium dialysis |
determines how much of he drug is free bound or bound t protein |
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Scatchard Analysis- one drug |
v/Df vs protein fraction bound(v) the slope is the association constant and the y intercept |
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the slope gives x-intercept and y intercept divided by the slop gives |
the binding constant the number of sites |
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equations must be modified to account for |
multiple types of binding sites multiple binding sites leads to a complex scatchard plot |
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an important application of drug- protein binding is |
determining the fraction of free drug, since this is the fraction that has biological effects |
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drugs that are highly bound has a
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create significant drug interactions |
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when sites do not greatly exceed drug molecules |
the total drug concentration effects the free drug concentration |
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when the initial concentration of free drug is low the addition of competing drugs |
can have large effects the free drug concentration and thus the pharmacological effects |
