Chemistry Help Please!! Xx

[suahgtr]

The drug albendazole contains a benzimidazole ring which is amphoteric. It has two pKa values, 9.51 and 4.27. Describe what ionisation state(s) this drug will be in when in blood (pH 7.4), stomach acid (pH 1.8), and bile (pH 8.5). Explain why?

[davebro]

Sorry - not a homework answer site!

[theprof]

I'll not provide you with a comprehensive answer as it strikes me that there are fundamental concepts that you appear not to understand here.

All the same, I'll give you some guidance. An aqueous solution of albendazole at a pH of 1.2 is about 900 micrograms per ml. At pH 5 it's even less. It's evident from this that albendazole cannot be absorbed from any mammalian GI tract unless albendazole is solubilised.

You need to read up on the importance of pKa in drug metabolism to fully understand the concepts involved. Many drugs fall within the category.