Can aqua conservans be used in nasal drops, or is it correct that it may be toxic to the cilia, as suggested by a colleague?

What is the best way to prepare a cleansing milk for acne using 35 g propylene glycol, 40 g PEG 4000, 25 g PEG 1500, 10 g Calendula MT, 10 g Arctium lappa MT, 30 g sweet almond oil, and distilled water up to 250 g, and can PEG 400 be used as a substitute for PEG 1500 to resolve the processing issues with the almond oil caused by the lack of an emulsifier?

How should I prepare the following shampoo based on cade oil: Hydrolan 20 g, lactic acid 20 g, sodium lauryl sulfate 100 g, chloramphenicol 10 g, cade oil 10 g, salicylic acid 10 g, and water up to 500 ml?

Why does Affusine, a cream containing fusidic acid, break after adding metronidazole to a prescription of hydrocortisone, metronidazole, and Affusine cream (containing fusidic acid, cetyl alcohol, glycerol, paraffin, polysorbate, HCl, and water), is there a pH problem between metronidazole and fusidic acid, and can this be easily resolved by adding an extra w/o emulsifier such as Arlacel?

Regarding the proposed formula on the website for processing oxybutynine into syrup, is there any data available concerning the shelf life and stability of this preparation, given that the bottle being produced must remain stable for 2 months?

What is the recommended composition for a mouth gel containing tetracycline to treat a painful aphthous ulcer, given that a prescription exists for a 5% tetracycline HCl mouthwash but a local gel application may be more appropriate?

What are the stability problems of a solution containing 3 grams of Phenobarbital sodium and purified water up to 300 cc?