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15 Cards in this Set
- Front
- Back
Name the routes of drug administration
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enteral (oral, sublingual, rectal)
parenteral (intravascular- IV or IA) subcutaneoas(sc) other (inhalation, intranasal,intrathecal /intraventricular,topical,transdermal) |
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effect of pH on drug absorption
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henderson-hasselbach equation:
ph=pKa+log(non-protonated species/(protonated species) |
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bioavailibilty
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is fraction of administered drug that reaches the systemic circulation (70%)
(= AUC oral/AUC injected x100) |
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factors that influence bioaivailibilty
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- first-pass hepatic metabolism (eg propanolol,
lidocain) - solubility of drug (eg hydrophilic & very hydrophobic poorly absorbed) chemical instability (eg penicillin G, Insulin) - nature of drug formation (particle salt, salt form |
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Bioequivalence
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if drugs show comparable bioavaililibity and similar times to achieve peak blood concentration
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therapeutic equivalence
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have comparable efficacy and safety
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drug distribution depends on
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blood flow
capillary permeability (capillary structure & drug structure) binding of drugs to proteins |
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blood brain barrier
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-lipid soluble durgs readily penetrate into the CNS
-ionized or polar drugs fail |
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Volume of Distribution (Vd)
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Vd = D/C (in absence of elimination)
D = total amount of drug in the body C = Plasma concentration of the drug |
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Binding capacity of albumin
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low capacity =(1 drug molecule per albumin
molecule) high capacity =(a number of drug molecules per albumin molecule) |
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Class I drugs
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= if the dose of drug is less than the binding capacity of albumin
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Class II drugs
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= if the dose of drug is greater than the binding capacity of albumin
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drug displacement
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= if class I and class II drugs are given simultaneously
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drug metabolism
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kinetics
- first-order v= Vmax[C]/Km+[C] -Zero-order (aspirin, ethanol, phenytoin) v = Vmax[C]/[C]=Vmax v+ |
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reactions of drug metabolism
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Phase I
- phase I utilizing the p450 system -phase I not involving P450 Phase II - consist of conjugatioin reactions |