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25 Cards in this Set
- Front
- Back
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a. Define drug disposition b. Drug Disposition is an example of Pharmaco___ |
a. The processes a drug is subjected to by the body upon administration b. Pharmacokinetics |
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Name the 4 processes involved in drug disposition |
1. Absorption 2. Distribution 3. Metabolism 4. Excretion ADME |
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Name the 6 forms of administration (+ what each form is associated with) |
1. Rectal/Rectal (Gut) 2. Intramuscular (Muscles) 3. Intravenous (Blood plasma) 4. Percutaneous (Skin) 5. Inhalation (Lungs) 6. Intrathecal (CSF) |
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The mode of administration has an effect on what? |
How much of drug reaches the bood Plasma |
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How much of the drug that reaches the blood plasma depends on what? |
How many membranes the drug has to move through (i.e. the mode of adminstration) |
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a. Define Bioavailibilty b. What is the symbol for bioavailability? |
a. The Fraction (F) of the administered dose which reaches the Systemic Circulation b. (F) |
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a. Which mode of administration has the most efficient bioavailibility? b. What might a poor bioavailability reflect? (to do with drug) |
a. Intravenous (IV) injection = 1 b. High Gastric instability |
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Briefly describe the phenomenon of First Pass Metabolism |
Where the concentration of a drug is significantly reduced (via metabolism by liver + gut wall) before the drug reaches systemic circulation |
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- When a drug is administered orally, it is absorbed by the __(a)__ - It then enters the __(b)__ - Here it is carried through the __(c)__, into the __(d)__ before it reaches the __(e)__ |
a. Digestive system b. Hepatic portal system c. Portal vein d. Liver e. Systemic circuit |
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Name 5 factors which affect drug absobtion |
1. Gastric motility (how quickly drug moves) 2. Nature of drug 3. Area of absorption surface 4. Blood flow at absorption surface 5. Ingestion of food - Plasma protein binding |
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- Most drugs are either __(a)__ or __(b)__ - They therefore exhibit __(c)__ - __(d)__ are not lipid soluble |
a. Weak acids b. Weak bases c. pH dependant ionization d. Ionized species |
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a. Name the 4 different routes of absorption across a lipid membrane b. What is the major route (most common) out of the 4? |
a. 1. Diffusion through lipid 2. Diffusion through aqueous channel 3. Carrier mediated 4. Pinocytosis b. Diffusion through Lipid |
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Diffusion through aqueous pores/ion channels: a. What kind of molecules diffuse via this route? b. Give an example |
a. - Very small - Less than 1000Da - Water soluble b. Lithium (small + monovalent) |
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Carrier-mediated diffusion: a. Via what processes do carriers use to cause diffusion? b. Name 3 examples of important sites of transfer (using this mode of diffusion) c. Name a downside of this mode of diffusion |
a. Facilitated diffusion/Active transport b. - Blood-brain barrier - Renal Tubule - Gastrointestinal tract c. Carriers/transporters may become saturated, hence limiting the rate of drug permeation |
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Pinocytosis: a. What kind of molecules usually diffuse via thi mode? b. Give an example |
a. - Macromolecules - Greater than 1000Da b. - Insulin - Crossing the blood-brain barrier |
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Diffusion through lipid membranes: a. What kind of molecules diffuse via this route? b. Dependent upon what 2 things? c. Degree of permeation is dictated by what? |
a. - Small - Lipid soluble - non-polar b. - SA of barrier - Blood flow at barrier c. Fick's Law |
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a. Briefly describe Fick's Law b. Which factor(s) in Fick's law are inversely proportional? c. What EXACTLY does Fick's law show? |
a. The factors which give an indication of how easily a drug diffuses through a lipid membrane b. (W) thickness of membrane c. The amount of drug which diffuses over time i.e. dQ/dt |
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e. Which form of a drug is lipid soluble? |
a. HA b. A- c. BH+ d. B e. Non-ionized form |
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- A highly lipid soluble drug is subject to a large __(a)__ - It will diffuse __(b)__ than a drug of lower lipid solubility |
a. Transmembrane concentration gradient b. More rapidly |
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a. What is the symbol for the dissociation constant? b. When is the dissociation constant equal to the pH? |
a. pKa b. pKa=pH when 50% of the drug molecules are ionized |
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Write down the Henderson-Hasselbach equations for both weak acids and weak bases |
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Describe the phenomenon of ion trapping |
When an ionized drug becomes trapped on one side of the membrane which divides compartments with different pHs |
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a. What are the 5 different body departments? b. Which body department is the largest c. WHich body department is the smallest? |
a. - Plasma water - Interstitial water - Intracellular water - Transcellular water - Fat b. Intracellular water c. Transcellular water |
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a. Define Volume of Distribution b. What is the formula for volume of distribution? c. What is the Volume of distribution a measure of? |
a. The volume of water required to contain the total amount of drug in the body at the same concentration as that present in the plasma Cp b. Vd = Dose/Cp c. The extent of distribution |
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If a drug has a high Vd, name 3 things this shows |
1. High lipid solubility 2. Low charge (non-polar) 3. Low plasma protein binding |
