What could be the cause of "petrification" in an ointment for hemorrhoids composed of 10 g zinc peroxide 50%, 10 g zinc oxide, 10 g corn starch, 30 g Orabase, and paraffin oil up to 85 g, which is packaged in an aluminum tube and has recently been prepared using the same raw materials?

Given that a patient is allergic to cocamidopropyl betaine, cocamidodiethanolamide, phenoxyethanol, methyldibromoglutaronitrile, perfumes, formaldehyde, and formaldehyde releasers (imidazolidinyl urea and diazolidinyl urea), and the Dermato KUL program recommends only Widmer Remederm shampoo, is this shampoo safe despite containing PEG-7 glyceryl cocoate (Cetiol HE) with a coconut fatty acid chain, or is the allergy specifically limited to coco-amido compounds?

When preparing a solution containing 1% estradiol valerate, 1.5% sodium lauryl sulfate, and antiseptic alcohol up to 100%, a flake-like white precipitate forms after dissolution through light heating; would using methanol instead of antiseptic alcohol, considering the solubility data in Martindale, help resolve this issue?

Does anyone know a formula for a mouth gel with bacitracine and neomycine that can be processed in the Fagron mouth gel base?

Diltiazem gel was always prepared with hydroxyethylcellulose, but since this raw material is no longer available, which alternative do you recommend?

What is the best way to prepare acetylcysteine 5% eye drops, given that I cannot find an E-value for acetylcysteine?

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