The present study aimed to evaluate the stability of active pharmaceutical ingredients (APIs) from different pharmacological classes in a compounded oral suspending vehicle. Oral suspensions of amoxicillin trihydrate (50 mg/mL), clozapine (25 mg/mL), indomethacin (5.0 mg/mL), levodopa/carbidopa (10.0/2.5 mg/mL), levothyroxine sodium (T4, 25 µg/mL), lomustine (4.0 and 10.0 mg/mL), methyldopa (25 mg/mL) and procarbazine (10.0 mg/mL) were formulated in SyrSpend^® SF PH4 and the stability was monitored for up to 90 days, except for amoxicillin trihydrate, which was evaluated for 30 days only. The APIs’ stability was determined by measuring percent recovery using stability-indicating high-performance liquid chromatography (HPLC or UHPLC) or titration (amoxicillin trihydrate only). The stability of amoxicillin trihydrate, clozapine, indomethacin and levodopa/carbidopa were studied at both refrigerated (2–8 °C) and room temperature (20–25 °C). Lomustine, procarbazine, and methyldopa were studied at refrigerated temperature only. Our data demonstrated promising stability for the compounded suspensions containing various APIs, investigated in SyrSpend^® SF PH4, as all APIs exhibited stability throughout the study duration and met content uniformity criteria. These findings lead to the conclusion that the tested compounded oral suspensions present a viable approach for creating personalized, age-appropriate formulations. The capacity to ensure dose consistency and stability using APIs from diverse pharmacological classes renders them suitable choices for both pediatric and geriatric patients.

An increasing number of pharmacies around the world are producing hair solutions and foams containing minoxidil for alopecia, commonly using ready-to-use vehicles such as TrichoSol^TM or TrichoFoam^TM. However, it is paramount to determine the chemical and microbiological compatibility of these formulations so they can be safely implemented as vehicles of choice. Also, these products usually suffer from a change of color over time, which leads to many patients prematurely discontinuing treatment. As long-term treatment is recommended, this study aimed to assess the physical–chemical and microbiological stability and investigate the color change of compounded minoxidil formulations. For that, HPLC analyses and antimicrobial effectiveness testing were conducted in a bracketed study covering concentrations from 1.0% to 7.0% of minoxidil. HPLC, pH, and metals in 5.0% minoxidil compounded products were determined using ICP-MS to evaluate the mechanisms involved in their color change. The stability of the products varied from 120 to 380 days. The color change was remarkably noticeable, but apart from this parameter, no other quality attribute was affected throughout this period, including minoxidil content, which presented only minor fluctuations. No precipitation was observed, and pH was relatively stable. It is not expected that this yellow color will impact effectiveness. Finally, we created an indicative color chart of the behavior of minoxidil in the studied vehicles.