Morphine and diamorphine (heroin) are both opioids.

Explain why diamorphine is more potent than morphine using section 37 of the data booklet.

morphine has hydroxyl/OH groups/is more polar AND diamorphine has ester/ethanoate/acetate groups/is less polar/is lipid soluble

crossing blood brain barrier is easier for non-polar/less polar compounds/for lipid soluble compounds

Accept “alcohol/hydroxy” for “hydroxyl” but not “hydroxide”.

Accept "fats" for "lipid".

[2 marks]