What is the use of nystatin drops for the treatment of the external auditory canal?

Do you know if metronidazole is incompatible with sunscreens such as octocrylene, given that metronidazole must be incorporated into SVR Rubialine 50+?

Is it possible to prepare capsules containing potassium and magnesium aspartate, given that a hygroscopic mixture is formed causing the powder to clump, and even when processing the two active ingredients separately into capsules, the magnesium aspartate capsules still showed clumping over time?

What is a suitable formula for a dental gel containing doxycycline as the active ingredient, as requested by a periodontist, given that such a preparation is available abroad in countries like Canada and the Netherlands?

What is the reason for a hemorrhoid ointment containing 4 mg hydrocortisone acetate, 4 mg lidocaine, and 8 mg diphenhydramine HCl in a PEG base (40% PEG 4000 and 60% PEG 400) becoming too hard to squeeze out of the tube after four weeks, and what is the solution, such as adjusting the PEG ratio, given that the commercially available PEG ointment from Purna is no longer available?

What is the best way to have Nerisona ointment prepared as a magistral formulation?

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