Regarding the following preparation of hydroquinone 5%, tretinoin 0.035%, and hydrocortisone acetate 1% in cremor non-ionicum aquosus, will it remain stable for 2 months?

Will the following cream remain stable for 2 months: hydroquinone 5%, tretinoin 0.035%, and hydrocortisone acetate 1% in cremor non-ionicum aquosus?

Is it possible to prepare elastic collodion yourself by adding 2% castor oil to standard collodion (e.g., from Fagron) since the wholesaler no longer provides collodion with castor oil, or can standard collodion be used directly for a preparation containing 10% salicylic acid, 10% lactic acid, and 10% acetic acid in 100% elastic collodion?

What causes the light brown discoloration during storage of a pediatric analgesic gel containing 4g lidocaine HCl, 500mg tetracaine HCl, and 181.9mg adrenaline tartrate in HPMC gel (pH 7), and would replacing the salts with bases like lidocaine and benzocaine, potentially using carbomer gel as a base, resolve the stability issues of adrenaline tartrate?

Is it possible to magistrally prepare a flavorless toothpaste for a patient with numerous allergies, including an allergy to all types of aromas, given that existing products labeled as flavor-free still contain aromas or menthol upon inspection of their composition?

Since the preparation of sugar syrup seems not so simple, why is it that no single company manages to produce it with a reasonable expiration date?

What is the explanation for the hard sediment formed in a syrup containing 2 g of crushed sertraline tablets and 200 mg of xanthan gum (moistened with glycerol) in 200 ml of purified water, and can it be assumed that the sertraline has dissolved while the sediment consists only of tablet excipients?