State in which region of the liposome, $A$, $B$ or $C$, each of the following would be transported. A hydrophilic moisturiser. A fat-soluble vitamin.
For one of the areas, $A$, $B$ or $C$, suggest why it would be unsuitable for carrying either molecule.
Name a functional group in drug molecules that could be decomposed by acid in the stomach.
One of the most common advances in delivering a wide variety of pharmaceutical products has been the use of liposomes. These are artificial spheres made from phospholipids with an ionic phosphate ‘head’ and two hydrocarbon ‘tails’.
When liposomes carry drugs, their chief role is to stop the drug molecules being broken down as they pass through the digestive system.
Name the reaction type that would lead to such a breakdown.
Sirolimus is used to prevent possible rejection by the body after kidney transplants. Circle two bonds, each belonging to a different functional group that could be digested.
Sirolimus is only sparingly soluble in water, which greatly lowers its effectiveness when administered orally or by injection. To improve its effectiveness when taken orally, nano-sized crystals of the drug combined with poly(ethylene glycol) or PEG (shown below) are produced. $\mathrm{HO-(CH_2-CH_2-O)_n-H}$
Suggest the meaning of the term nano-sized.
Suggest which part of the PEG molecule the drug would attach to.
Why would bonding the drug to a PEG molecule improve its water solubility?