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20 Cards in this Set
- Front
- Back
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Absorption |
-passage of intact drug from administration site into systemic circulation |
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Distribution |
-Reversible movement of drug between systemic circulation and the tissues |
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Metabolism |
-Irreversible enzymatic alteration of the drug |
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Excretion |
-Irreversible passage of the drug/metabolite out of the body |
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Absorption Rate Constant (Ka) |
-primary PK parameter -dependent on: blood flow,gastric emptying, GIT motility |
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Oral Bioavailability (F) |
-primary PK parameter -dependent on: gastric emptying, acid secretion,enzyme activity, GIT motility |
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Hepatic Clearance (Cl H) |
-primary PK parameter -dependent on: hepatic blood flow, binding in blood, intrinsic clearance |
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Renal Clearance (Cl R) |
-primary PK paramter -dependent on: renal blood blow, fraction unbound drug, active secretion/reabsorption |
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Volume of distribution (Vd) |
-primary PK parameter -dependent on: fraction unbound, tissue binding, body composition size |
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Elimination of half-life |
-secondary PK parameter -dependent on primary PK paramters --> Vd and Cl S |
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Elimination rate constant |
-secondary PK parameter -dependent on Vd and Cls |
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Fraction excreted unchanged |
-secondary PK parameter -dependent on Cl R and Cl S` |
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Oral Dosing |
Advantages: convenience of administration cheap avoidance of high toxic concentrations Disadvantages: inefficient (erratic bioavailability) first pass effect |
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Buccal/Sublingual |
Advantages: by-pass the liver --> first-pass effect rapid absorption drug stability Disadvantages: small concentrations inconvenient/discomfort |
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Rectal |
Advantages: by-pass the liver avoid GIT side effects Disadvantages: erratic absorption patient compliance |
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Parenteral Route - Intravenous |
Advantages: rapid onset total dose Disadvantages: hard to find vein trained personnel high Cp --> toxicity possibility |
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Parenteral Route - subcutaneous |
Advantages: self-administered slow but complete absorption Disadvantages: can be painful smaller doses |
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Parenteral Route - intramuscular |
Advantages: rapid absorption a depot effect possible Disadvantages: erratic absorption trained personnel |
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Noyes-Whitney Equation |
dC/dt = (D/h) (S) (Cs -C) dC/dt - rate of dissolution D - diffusion coefficient, affected by temp h - width of diffusion layer, affected by agitation s - surface area of the drug, affected by particle size (smaller size --> incr. SA) Cs - drug conc in diffusion layer C - conc in bulk solution |
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What are factors that affect the pH of the drug environment? |
-dosage form ingredients -salt form of drug -region of GIT -disease -co-administered drugs |
