Changes

===Properties of the Drug===

===Properties of the Drug===

* Lipid solubility - the more lipid soluble a drug the easier it is absorbed across the bilayer

* Lipid solubility - the more lipid soluble a drug the more readily it is absorbed across the bilayer

* Chemical nature - ie. Is it basic or acidic? Is it ionised or not?

* Chemical nature - ie. Is it basic or acidic? Is it ionized or not?

* Molecular weight

* Molecular weight- lower molecular weight compounds are more readily absorbed than large M.W. compounds.

* Stability in the gastro-intestinal tract - only applies to orally administered drugs

* Stability in the gastrointestinal tract- this only applies to orally administered drugs

===Physiological Variables===

===Physiological Variables===