What can monostearin be replaced with in calcium hydroxide oil liniment PB V when it is unavailable?

Can a nitrofurantoin suspension (30 mg/5 ml) be prepared using xanthan gum (a prefabricated suspension base), given that the Therapeutic Magistral Formulary (TMF) and other formularies like the USP specify formulas based on a dispersion of microcrystalline cellulose and sodium carmellose (CMC)?

Why do crystals sometimes appear after a certain period in a magistral Actifed-type cough syrup containing 400 mg codeine phosphate, 4 g guaifenesin, 1.2 g pseudoephedrine, 0.8 mg triprolidine HCl, 0.6 g raspberry aroma, 0.45 g bromoform aroma, and syrup up to 100 ml, even when 10 ml of water is used to dissolve the medicinal ingredients?

Why are sodium thiosulfate crystals prescribed in a W/O cream containing 25 g sodium thiosulfate crystals, 5 g zinc oxide, and hydrated petrolatum up to 100 g, is the use of the crystal form or the 5.H2O variant essential, and what are the specific preparation and storage requirements for this formulation?

How can the separation of a cream containing 0.5% salicylic acid, 10% urea, 10% sodium chloride, 10% glycerol, 10% lactic acid, and 10% liquid paraffin in buffered cetomacrogol cream up to 300g be resolved?

Is it necessary to use a racemic mixture of amphetamine sulfate to prepare eye drops, or can dexamphetamine (amphetamine sulfate D) be used instead, given that this is an alternative to the unavailable benzedrine (hydroxyamphetamine HBr) 1% collyrium, and considering that Middelheim Hospital uses a formula consisting of 0.1g racemic amphetamine sulfate, 165mg boric acid, 1mg benzalkonium chloride, and purified water up to 10 ml?

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