What does it mean if a drug is amphiphyllic
and how would this affect its interaction with the plasma membrane and with respect to receptor binding

if it binds to a site distinct from the agonist binding site, could
it potentially bind deep within a 7TM bundle?

The correct spelling is: Amphiphilic

It means to have both hydrophobic and hydrophilic properties.

if it binds to a site distinct from the agonist binding site, could it potentially bind deep within a 7TM bundle?

You would have to establish what the local enviromental conditions were to determine if the drug will have it's equilibrum shifted to a more hydrophilic or hydrophobic properties. If it particulary hydrophibic, it may get sequestered in the plasma membrane and interact with a 7TM receptor at a membrane interface. If it is more hydrophilic it may well find a site in the more protein rich hydrated enviroment of the receptor.

Thanks guys!

So would such a drug only be either hydrophobic or hydrophilic depending on the environment but never both at the same time?

Stix said:

Thanks guys! So would such a drug only be either hydrophobic or hydrophilic depending on the environment but never both at the same time?

A drug could be amphiphilic (hydrophobic and hydrophilic) in the same time. This is the case of biopolymers (block copolymers) which are composed from a hydrophilic as well as a hydrophobic part. Usually, those copolymers rearrange spontaneously in an aqueous solution and form polymeric micelles.

Definition:


http://en.wikipedia.org/wiki/Amphiphilic

Stix said:

What does it mean if a drug is amphiphyllic and how would this affect its interaction with the plasma membrane and with respect to receptor binding if it binds to a site distinct from the agonist binding site, could it potentially bind deep within a 7TM bundle?