Compound A is a poorly soluble weakly basic drug. You attempt to apply different strategies to overcome this issue.

a) Please explain how particle size reduction increases the solubility of compound A. (3 marks)

b) You apply amorphous technology to improve the solubility of Compound A.

i) Does amorphous form have a melting point? Why? (3 marks)

ii) Please explain how amorphous drug can increase solubility (3 marks)

iii) Upon storage under a humidity of 60%, the amorphous compound A fails to develop an increase in solubility. Please explain this phenomenon. (2 marks)

c) You add a Compound A (the free form) injection (clear solution) into a normal saline IV bag.

i) Precipitation is observed. Please explain this phenomenon. (2 marks)

ii) To increase the solubility of Compound A, a HCl salt is prepared. However the HCl salt still cannot be dissolved in normal saline. Please explain this phenomenon. (2 marks)