please answer all parts and explain

QUESTION TWO (50 MARKS) Answer ALL parts (a) to (d) (a) The role of an excipient in a drug formulation can change depending on It's concentration. Draw the structure of a surfactant with reference to the terms anionic, cationic and non-ionic. Describe three potential functions of a surfactant as an excipient in a drug formulation noting (i) role (ii) method of action (ili) examples (15 marks) (b) Emulsions may be used to disguise the taste of an unpalatable drug. Using Cod liver oil as the drug write out a potential formulation. Explain the role of the chosen excipients and how they contribute to the drug product. List examples. Write a short note on the extemporaneous preparation of this medication. What are the possible advantages compared to cod liver oil capsules. [25 marks) (c) The shelf life/expiry date and packaging of a medication is influenced by a number of different factors. Discuss this statement in relation to eye drops and eye ointments. [10 marks)