Pharmaceutical Factors Flashcards
What happens to the risk of bioavailability problems as you slow the rate of absorption of a drug?
Risk of bioavailability problems increases
Order the following drug preparations in order of rate of absorption: aqueous solutions, suspensions, coated tablets
Aqueous solutions absorbed fastest (lowest risk of bioavailability problems), then suspensions, then coated tablets absorbed slowest
Why do some drugs have an enteric coating (EC capsules e.g. Omeprazole)
To prevent them being digested in the stomach before they can take effect
What is the difference between ibuprofen and ibuprofen lysine?
Ibuprofen lysine absorbed more rapidly, but also has more rapid elimination due to shorter half life
Why are EC/enteric drugs useful? Give an example!
Prevent drug being dissolved immediately and prevent irritation of stomach e.g. oral steroids should have EC to avoid local effects on stomach
When are sustained release preparations (SR preparations) used? How to they work?
. When a drug has a short half-life but you need the drug to be released slowly over time
. Drug dissolved layer by later (like an onion) so drug can be released and absorbed by body more slowly over time
Morphine can come as a Morphogesic or as Oramorph. What is the difference between these forms?
. Morphogesis is SR drug to give continuous 12 hour pain relief
. Oramorph- suspension to provide breakthrough pain relief
What type of drug is Omeprazole?
Proton pump inhibitor
Why is Omeprazole given as an EC capsule?
Omeprazole is acid labile so would dissolve in stomach acid
What is Omeprazole used to treat? How does it work?
. Heartburn
. Capsule polymer breaks down in duodenum
. Drug absorbed in blood, inhibits PPs in parietal cells to inhibit secretion of HCl
