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18 Cards in this Set
- Front
- Back
- 3rd side (hint)
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the approximate pH of the jejunum is:
a. 4-5.5 b. 7.0-7.5 c. 1-2 d. 5.5-7.0 e. 3-4 |
d. 5.5-7.0
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the stomach has the lowest pH of the GI tract, the ileum, colon and rectum have the highest pH of the GI tract.
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the approximate surface area of the stomach is:
a. 100 cm^2 b. 200 cm^2 c. 5 m^2 d. 200 m^2 e.3.5 m^2 |
e. 3.5 m^2
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the oral cavity has the smallest surface area in the GI tract. the ileum has the biggest surface area in the GI tract.
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approximate residence time of the duodenum is:
a. 0.5-0.75 hours b. 5-7 hours c. 1-60 hours d. seconds to minutes e. 1.5 hours |
a. 0.5-0.75 hours
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the esophagus has the shortest residence time, while the
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Although the large surface area of the intestine helps with drug absorption, the fact that the intestinal epithelium contains ___, ___, and ____ can decrease drug absorption
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proteins, enzymes and electrolytes (such as glycoprotein, lymphoid cells, Peyer's patches)
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if you have a drug that is primarily absorbed in the small intestine, what effect would you expect delayed gastric emptying to have on drug absorption?
a. increase absorption b. decrease absorption c. not have an effect on absorption |
b. decrease absorption
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certain foods should be avoided while taking tetracycline, such as milk and spinach. why should these foods be avoided?
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complexation can occur between the drug and Fe, Ca and Mg salts. this will decrease the absorption of the drug.
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true/false: pH affects a drugs lipid solubility (i.e. drug passage across lipid membrane).
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true.
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What three things affect drug passage across a lipid membrane?
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molecular weight, surface area of membrane, and lipid solubility
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in what way does pH influence drug absorption?
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pH influences the ionization of the drug. ionized form of drug does not cross lipid membrane very well, while the unionized form is more readily absorbed.
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P, known as the partition coefficient, is an estimate of what characteristic of a drug?
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it is an estimate of the drug's lipophilicity.
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What happens to drug activity if P (partition coefficient) is increased?
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as P increases, lipid solubility increases.
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According to the rule of fives, if you have more than ___ H bond donors (expressed as the sum of OHs and NHs), you will have poor absorption or permeation.
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5
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According to the rule of fives, if you have more than 10 _____ acceptors (expressed as the sum of Ns and Os), you will have poor absorption or permeation.
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H-bond
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According to the rule of five, if the molecular weight of the drug is over ____, you will have ppor absorption or permeation.
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500
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What is the value for optimal log P? What value of log P is expected to lead to poor absorption or permeation (according to rule of fives)?
a. 5, 3 b. 3, 5 c. 1, 3 d. 5, 10 e. 2, 4 |
b. 3, 5
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What three factors (specifically covered in the notes) influence drug concentration in the blood once drug is absorbed from the GI tract?
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blood flow, binding to plasma proteins, hepatic metabolism
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keep in mind that during a passive diffusion process that what is driving diffusion is a concentration gradient.
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Which route of passive diffusion is considered the most significant pathway?
a. passive transcellular b. passive paracellular c. carrier-mediated uptake d. carrier-mediated efflux |
a. passive transcellular
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true/false: passive transcellular diffusion is a saturable pathway
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false. you do not utilize any binding sites that can be saturated in the process of passive transcellular diffusion.
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