Dear Dr. Alessia La Rocca

You should add an appropriate volume of DMSO to the retinoic acid powder, ensuring all the powder is fully dissolved. Gently warm the solution to 37°C for 3-5 minutes to aid in dissolution. Then you create aliquots of the retinoic acid solution dividing the solution into smaller, manageable portions. These aliquots are for future use to avoid multiple freeze-thaw cycles. Store the aliquots at -20°C for long-term preservation. Please note that even at -20°C, retinoic acid solution can degrade over time, so it is recommended that you use the aliquots within the recommended timeframe (usually up to 4-6 months).

It is better to dissolve the entire 100mg powder in DMSO once you open the product because retinoic acid is considered as a hygroscopic compound, meaning it can absorb moisture from the surrounding environment, which can negatively impact its stability by altering its properties, including its purity and flowability. Otherwise, you may store retinoic acid powder in a way that protects it from moisture as it is important to maintain its quality.

Regards,

Malcolm Nobre