How to modify bioavailability of drug?

[myvow]

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i i think acidic medium =stomach, so drug interaction can be applied in this case?using some drug to alter the motility rate of gastric emptying?

ii I think the drug is OK because extraction ratio is not too high,but I have no idea to explain in detail

iii it must change the rote of administration because the drug will be digested by gastric acid.


can anyone give me an advice if my answer is valid?
Thank you very much

 

[myvow]

Are any one here?

 

[Cawolf]

This is an MCAT question?

 

[erythrocyte666]

yeah, this looks more like homework than mcat practice...
I would assume people in the pharmacy or PCAT threads would have some more expertise than us MCATers.
I at least am not familiar with what's a high stomach hydrolysis ratio or a high hepatic extraction ratio...

 

[Hailstorm]

For the first one, you could modify the drug so that it's less susceptible to acid hydrolysis, but what they probably want is using an enteric coating. You could also do things like combine it with an antacid, or possibly taking it with/without food.

I'm not really sure if you're mostly just concerned with the first pass effect or with the halflife of the drug for ii, you could use. Aside from modifying the drug, the most basic solution would be to just take more of the drug - perhaps as part of a time-release capsule if you need a constant dosing and its halflife is problematic. Another option would be doing something like how ritonavir boosting is used in HIV treatment, you'd be looking for something that inhibits P glycoproteins or the cyt-p450 enzymes.

for iii I presume your big concern would be proteases in the digestive system - I don't know whether an enteric coating would do anything - maybe you can take it with food or with some sort of pepsin/trypsin/chymotrypsin inhibitors?

 

[myvow]

For the first one, you could modify the drug so that it's less susceptible to acid hydrolysis, but what they probably want is using an enteric coating. You could also do things like combine it with an antacid, or possibly taking it with/without food.

I'm not really sure if you're mostly just concerned with the first pass effect or with the halflife of the drug for ii, you could use. Aside from modifying the drug, the most basic solution would be to just take more of the drug - perhaps as part of a time-release capsule if you need a constant dosing and its halflife is problematic. Another option would be doing something like how ritonavir boosting is used in HIV treatment, you'd be looking for something that inhibits P glycoproteins or the cyt-p450 enzymes.

for iii I presume your big concern would be proteases in the digestive system - I don't know whether an enteric coating would do anything - maybe you can take it with food or with some sort of pepsin/trypsin/chymotrypsin inhibitors?

Thanks!
Your comment is really help.