Regarding the composition of a 0.1% tretinoin lotion for acne-prone oily skin, what is the best base—denatured ethyl alcohol, isopropyl alcohol, or a mixture of both—can propylene glycol be added and in what ratio, how long can such a lotion be stored, and is refrigerated storage beneficial?

How can the needle-like precipitation of salicylic acid be avoided in a preparation containing 0.3 g salicylic acid, 10 mg vanillin, 5 ml ethanol (spiritus), 20 ml liquid sorbitol, and water up to 100 ml, given that precipitation occurs after 24 hours?

Why does a dentist request a sodium fluoride (NaF) dental gel with a pH of 4, and how much citric acid should be added to achieve this?

How can the crystallization of a solution containing 2% tetracaine HCl, 0.01% epinephrine, and physiological water up to 100 ml be prevented when stored in the refrigerator, given that acidification has no effect and despite a reference from Am. J Health-Syst Pharm. 53, 659 (1996) suggesting a stability of 26 weeks in a red-brown bottle under refrigeration?

How should a lotion for a baby's scalp be prepared if the prescribed composition consists of 3 g salicylic acid, 1 g hydrocortisone acetate, and spiritus dilutus up to 100 ml, considering a suspension based on hydroxypropyl cellulose (HPC) in 70% isopropanol?

What is the professional opinion regarding the preparation and therapeutic utility of a mouthwash frequently prescribed by stomatology and oncology services containing 300 mg hydrocortisone, 300 mg lidocaine HCl, 2.4 million units nystatin, 2 g NaCMC, peppermint spirit q.s., and water up to 500 ml, specifically addressing the use of NaCMC, preservation methods, and the inclusion of cortisone?

Which carrier (lactose, mannitol, or others) is adequate for diluting electrostatically regulated release granules (e.g., tamsulosin or duloxetine)?