Are there any potential incompatibilities in this cream?

What is the recommended approach for preparing a combination of a corticosteroid ester and erythromycin consisting of 36 mg betamethasone valerate and 1.5 g erythromycin base in hydrophilic anionic cream up to 50 g, specifically regarding the choice between buffering to pH 6.6 or 8.6 and whether hydrophilic anionic cream is equivalent to cetyl cream?

How do you prepare the following formula (shake lotion): 2g salicylic acid, 32mg betamethasone dipropionate, 25ml isopropanol, 40mg carbopol 934, 0.4ml NaOH solution, and aqua ad 50cc?

What is the recommended preparation method for a phenytoin cream intended for Sudeck's syndrome, given that the basis was not specified, it is the first time the physician is prescribing it following a specialist's recommendation, and while the APB suggested using a PEG or Natrosol gel basis, the latter is unavailable, there is no existing protocol for this preparation in Belgium, gabapentin cream or ointment was suggested as an alternative, and a formula developed by a Dutch pharmacy in collaboration with a neuropathic pain center is patented?

Why does this formula, consisting of 0.12% betamethasone valerate, 2% salicylic acid, 3% Lanette wax SX, 3% almond oil, and water up to 100% (300g total for a scalp emulsion), fail to emulsify even before the addition of salicylic acid and the corticosteroid, and is the addition of Tween missing from this formulation?

How can a 5 mg/mL oral suspension of riluzole be prepared magistrally starting from Rilutek tablets for an ALS patient with swallowing difficulties, considering that the pure substance is unavailable and a similar commercial product, Teglutik, exists abroad?

Regarding the preparation of 5 mg pilocarpine nitrate to be taken three times daily for dry mouth, as prescribed by an ENT specialist, is it permissible to use pilocarpine HCl if the nitrate form is unavailable, and how should the molecular weight conversion be calculated?