I'm looking for some input regarding stability issues I'm having..
I have samples at RT, samples at 50C and samples cycling between freezer/RT/50C. The samples at 50C are showing signs of instability but the samples in freeze/thaw cycle have gone through two rounds and show no issues at all... I thought freeze/thaw was more intense than just one temperature consistently... The issues that I'm experiencing at 50C consistently are not acceptable but the results of the current freeze/thaw are... I'm not sure what to really do with that information
Comments
Sussex Research Laboratories Inc.
www.sussex-research.com
The problem with making decisions about samples stored at 50C is that you're getting close to the melting point of some of the ingredients which can have effects on product stability that you would never see in real life. In this way, the 50C samples may not be usefully predictive of the future.
I'm doing a more accelerated F/T, from freezer to RT to 50C 3 times over and its going well after 2 cycles. @Perry would you say those results are more reliable?
Maybe I should have done 45C if that is more the standard, they may hold up at that temperature..
Sussex Research Laboratories Inc.
www.sussex-research.com
Sussex Research Laboratories Inc.
www.sussex-research.com
Sussex Research Laboratories Inc.
www.sussex-research.com
Sussex Research Laboratories Inc.
www.sussex-research.com
I think the problem is your Cetearyl Glucoside (and) Cetearyl Alcohol emulsifier. It tends to yield thin, runny emulsions that are not particularly heat stable, so it is not surprising that you are having difficulty at 50C in an accelerated testing scenario.
What happens to the emulsion if you remove it from the oven after several days at 50C and let it sit overnight? ... Does it revert back to the same or similar viscosity as your RT samples or does it seem to permanently lose viscosity? ... I suspect the latter.
I tried a few formulations with this emulsifier and ended up reformulating all of them with a different emulsifier. FWIW: I no longer use this emulsifier in any formulations.
See website for details www.desertinbloomcosmeticslab.com
Sussex Research Laboratories Inc.
www.sussex-research.com
See website for details www.desertinbloomcosmeticslab.com
Sussex Research Laboratories Inc.
www.sussex-research.com
This really comes down to a business risk decision. If you really think that the product may be subject to 50C for extended periods of time then you need to make sure it's stable at 50C, particularly since you now know that it will separate and not reconstitute when subjected to constant 50C for extended periods of time.
LOL, simply lowering your test criteria to 45C may give you a Pass where 50C gives you a Fail, but what does that really get you? A product that still fails at 50C. If you took that approach, then every product could be deemed stable if you simply continue lowering the test criteria at which you deem something to be stable until your product passes.
See website for details www.desertinbloomcosmeticslab.com
Well ... product stability is a subjective determination after all. Stability at 50C is a much more relevant requirement if you are shipping product in India, for instance, than if you are shipping in the US where air conditioned vehicles and warehouses are much more common.
See website for details www.desertinbloomcosmeticslab.com
If it fails 45C after 8+ weeks then that's another story.
Sussex Research Laboratories Inc.
www.sussex-research.com
I was just teasing with you Jonah. If you are comfortable at 45C and have had other formulations with this emulsifier pass on stability at 45C, then you should be in good shape.
See website for details www.desertinbloomcosmeticslab.com