At minimum, conduct accelerated stability testing at 40°C/75% RH for 3 months alongside real-time ambient and freeze-thaw cycling. Key parameters to monitor include pH drift, viscosity change, color shift, and azelaic acid assay (HPLC). A preservative efficacy challenge test is also mandatory for leave-on products sold in regulated markets. Ask your AJ Cosmo Labs cosmetic chemist to include a stability protocol in their project quote.
Read the full guide on Azelaic acid formulations →