Absorption Flashcards
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Define
Pharmacokinetics
(2)
Study and characterization of drug: ADME, with the aid of mathematical models which allow data to be interpreted.
What is the difference between
pharmacokinetics and Pharmacodyanmics?
(2)
Pharmacokinetics: Effect of body on drug
Pharmacodynamics: Effect of drug on body
Explain
Clinical pharmacokinetics
(1)
The application of pharmacokientics in the safe and effective therepeutic managment of the patient.
Summarise
Pharmacokinetics, Pharmacodynamics, Pharmacotherapeutics
(3)
- Pharmacokientics: ADME
- Pharmacodynamics: drug/receptor interaction
- Pharmacotherapeutics: Drug effect/response
State how we can use
The pharmacokientic properties of a drug
(3)
Dose and frequency of drug
How to change dose in certain medical conditions
How some drug interactions occur
Define
Abosrption
(1)
Movement of drug from site pf administration, across membranes and into the bloodstream
Note the factors
Which affect the rate of absorption
Red doors like working
(4)
- Route of administration
- Dose (concentration)
- Lipid-solubility of the drug
- Weak organic acid/base drugs
Draw a table
with routes of administration and their site of absorption
(10)
Draw table
Most drugs are weak organic acids/bases, what does this tell us?
- Most drugs are hydrocarbon molecules, sucg as aspirin, vitamins.
- They undergo ionisaiton/dissociation
- The pH of the solution as well as the pKa of the drug will tell us if the drug is in an ionised or non-ionised state.
Henderson - Hasselbach equation
(5)
pH = pKa + log (A- / HA)
- pH = -log(H+)
- pKa - dissociation constant for the acid
- A- -concentration of the conjugate base
- HA - concentration of the acid
Define
Passive diffusion
Movement of molecules from a higher concentration to a lower concentration, down a concentration gradient not requiring energy
Requirements of
passive diffusion
- Water solubility - almost all drugs are sufficiently water soluble
- Lipid solubility - some drugs lack the necessary lipid solubility
- In practice, passive diffusion depends mainly on lipid solubility
Draw a table with
Which molecules are effieicnet/ineffieicent in passive diffusion?
5|3
draw a table
Define
facilitated diffusion
(1)
Selective gateway allows entry of one group of molecules, but excludes all others.
What is
active transport
(3)
- Structurally selective
- Requires energy
- Can operate against the concentration gradient