Moreover, the drug's pharmacokinetic profile can be easily and significantly changed by adjusting factors that affect absorption.
[6] Passing through the esophagus to the stomach, the contents of the capsule or tablet are absorbed by the GI tract.
If a drug is supplied in a form that is not readily dissolved, it may be released gradually and act for longer.
The particle size reduction increases the specific surface area and the dissolution rate and does not affect solubility.
Later, esterases in the gastrointestinal tract (GIT) wall and blood hydrolyze these esters to release the parent drug.
Some molecules have special exchange proteins and channels to facilitate movement from the lumen into the circulation.
[vague] Ions cannot passively diffuse through the gastrointestinal tract because the epithelial cell membrane is made up of a phospholipid bilayer, comprising two layers of phospholipids in which the charged hydrophilic heads face outwards and the uncharged hydrophobic fatty acid chains are in the middle of the layer.
However, the reverse is true in the basic environment of the intestines—weak bases (such as caffeine) will diffuse more readily since they will be non-ionic.
Also, the chemists may develop prodrugs of a compound—these chemical variants may be more readily absorbed and then metabolized by the body into the active compound.
The solubility and permeability of a drug candidate are important physicochemical properties the scientist wants to know as early as possible.