Accelerated Stability Testing Question...

firstlightfirstlight Member
edited March 2019 in Advanced Questions

I've been lurking on this forum for a while and carefully read the posts so thanks for all the who add to the discussion, I've learned a lot.

I'm a hobbyist and have been making my own skin care products for a few years. I recently bought an incubator so I can do some accelerated stability tests so I can gift some of my creations :)

I starting testing the stability of a high BHA oil/water cream and within a few days in the incubator a few droplets of water have separated. Is this a bad sign or is this just condensation because the incubator is at about 38-39C, or 100-102F? Is their an acceptable amount of separation during accelerated stability tests to compensate for the high heat?

Thank you for any help! Very much appreciated...


  • Well I emailed lotioncrafter and they suggested that the cream was failing the stability test due to a phenomenon called "sweating" and that I should stabilize the water phase with more emulsifier, or a polymeric thickener or a solubilizer...
  • 40C isn't overly high and i would use 6mths at 40C to establish a 2year at RT shelf life although there'll be many comments/counterclaims based on the experience of others. Try centrifuging a aliquot of the emulsion, 5-10g or so. Run it for 30-40min at 4000 rpm (you can calc the g-force) if there's no separation -all good and you likely have condensation. 
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