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27 Cards in this Set
- Front
- Back
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What is Enteral administration?
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Any of form of administration that involves any part of the gastrointestinal tract.
Oral - easy, complicated, variable Sublingual (buccal) Rectal |
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What is Parenteral administration?
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By injection of infusion
IV IM Subcutaneous - localized effect |
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What are 4 other routes of administration?
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Topical - cal control of effect (skin)
Transdermal - sustained delivery Inhalation - Very rapid absorption, avoids systemic side effects Intranasal - rapid absorption, capillary plexus |
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What is Bioavailability?
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A measure of the rate and extent of therapeutically active drug that reaches the systemic circulation and is available at the site of action.
Expressed as the fraction of drug in the systemic circulation to drug administered |
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How is determined?
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By comparing plasma levels of drug after administration compared to IV injection (100% bioavailability)
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What is fraction Dose Absorbed?
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Fraction of oral dose that traverses the intestine intact.
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Put these dosage forms into order of descending bioavailability.
Suspension, Coated Tablet, Capsule, tablet, solution |
Solution
Suspension Capsule Tablet Coated tablet |
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From the plasma, where can a drug go to be excreted?
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1) Breast/Sweat Glands --> Milk/Sweat
2) Kidney --> Urine 3) Liver --> Bile --> Gut --> Feces 4) Gut --> Feces 5) Skin 6) Muscle 7) Brain --> CSF 8) Lung --> Expired air 9) Placenta --> Fetus |
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What 5 physiochemical factors affect bioavailability?
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Solubility
Ionization Dissolution Rate Chemical Stability Diffusion (Intraluminal) |
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What 6 physiological factors affect bioavailability?
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GI Transit
Bile secretion Transport Mechanisms Metabolism Regional effects Transporters/enzyme |
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What are the 2 phases of Drug metabolism?
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Phase 1 = Conversion to lipophilic compounds (Oxidation, Reduction, Hydrolysis)
Phase 2 = Conjugation (Glucuronidation) |
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Why are extremely hydrophilic and hydrophobic drugs both absorbed poorly across membranes?
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Hydrophilic - can't cross lipid rich membrane
Hydrophobic - are insoluble in the aqueous environment of the body Rapid absorption requires a combination of lipophilic and hydrophilic properties |
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What drugs are ideal for movement across membranes
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Hydrophobic, non-polar drugs with uniform electron distribution but are still soluble in an aqueous state.
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What 4 factors can influence Solution bioavailability?
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Chemical stability
Complexation Solubilization Viscosity |
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What 5 factors can influence Suspension bioavailability?
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Particle size/ surface area
Crystal form Complexation Inclusion of a surfactant Viscosity |
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What are the 2 phases of Drug metabolism?
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Phase 1 = Conversion to lipophilic compounds (Oxidation, Reduction, Hydrolysis)
Phase 2 = Conjugation (Glucuronidation) |
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Why are extremely hydrophilic and hydrophobic drugs both absorbed poorly across membranes?
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Hydrophilic - can't cross lipid rich membrane
Hydrophobic - are insoluble in the aqueous environment of the body Rapid absorption requires a combination of lipophilic and hydrophilic properties |
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What drugs are ideal for movement across membranes
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Hydrophobic, non-polar drugs with uniform electron distribution but are still soluble in an aqueous state.
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What 4 factors can influence Solution bioavailability?
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Chemical stability
Complexation Solubilization Viscosity |
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What 5 factors can influence Suspension bioavailability?
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Particle size/ surface area
Crystal form Complexation Inclusion of a surfactant Viscosity |
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What factors can influence the drug bioavailability of a Hard Gelatin Capsule?
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Particle Size/ Surface area
Salt form Crystal form Chemical stability Drug excipients Filling process Packing density Interaction between capsule shell and contents |
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Soft Gelatin Capsule?
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Solubility
Particle Size Nature of vehicle Inclusion of surfactant Inclusion of suspending agent Complexation |
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When pH is less than pKa, which form predominates?
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The protonated form
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What is diarrhea's effect on absorption?
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Decreases absorption
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What is the effect of delayed gastric emptying on absorption?
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It may decrease absorption by prolonging exposure of the drug to acidic environment longer.
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What is the effect of sympathetic/parasympathetic stimulation on absorption?
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Sympathetic - Decreases gastric emptying/intestinal motility and therefore may decrease absorption
Parasympathetic - Increases gastric emptying and intestinal motility |
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What is foods effect?
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It delays gastric emptying and may promote or impair drug absorption
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