Absorption Flashcards
What does a wider therapeutic range mean as far as drug safety goes?
Safer drug
What does a narrow therapeutic range mean as far as drug safety goes?
Less safe drug
Absorption is how
Drug enters blood or lymphatic system
If the drug conc. and action increase, then the absorption and distribution…
Increases
If the drug conc. and action decreases, then the metabolism and excretion will…
Decrease
Factors that influence absorption rate
- transportation type
- route of admin.
- physiochemical properties of drug
- drug conc.
- protein binding
- dosage forms
- circulation at site of absorption
Passive diffusion depends on
Concentration gradient, molecule size, lipophilic nature, temp., membrane thickness
Smaller molecule size, higher lipid solubility, and thinner membranes cause the diffusion rate to
Increase
Time for absorption PO
Mins to hours
(Is primary ROA)
Sublingual/buccal absorption time
3-5 mins
Rectal absorption time
5-30 mins
Enteral routes of administration
- PO
- Sublingual/buccal
- Rectal
Parenteral routes of administration
- IV
- SQ
- IM
Time of absorption for IV
- 30-60 sec
- 100% bioavailability
Time of absorption IM
10-20 mins
Time of absorption SQ
15-30 mins
Major factors that determine ROA in different species
- small intestine
- epithelial surface
- motility
- surface area
- efflux proteins (p-glycoprotein)
Rank solutions, capsules, suspensions, emulsions, slow release products, and tablets ROA in order from fastest to slowest
- solutions
- emulsions
- suspensions
- capsules
- tablets
- sustained release products
Lipid soluble and unionized drugs are absorbed faster or slower?
Faster
How do higher water partition coefficients affect absorption
Increases absorption
How do drugs that are ionized and larger than 50 daltons move across cell membrane?
Active transport
Drugs between 50-600 daltons move thru the cell membrane via
Passive diffusion
When the pKa and pH are equal, that means
50% of the drug is ionized
Unionized drugs pass through the membrane more difficult or easily?
Easily
