Comments on: How To Stability Test a Cosmetic Formula

By: Nina Caisido

Nina Caisido — Mon, 16 Apr 2012 02:18:18 +0000

Glad that I was able to share.. because I can see that some are missing the fact that we belong to different regions and the definition of room temperature varies. As for us in the Philippines, RT is rarely 25°C. And I can say that it is safe to use RT at 30°C, therefore conducting accelerated stability for 3 months at 45°C, can only give an estimated shelf life of 9 months at RT. In order to have at least 24 months shelf life, stability studies should at least be conducted at 4.5months @ 45°C. Thank you for all your help, Perry! More power!!

By: Perry

Perry — Fri, 13 Apr 2012 19:29:10 +0000

Nina,

Congratulations! That’s a big accomplishment to get into their stores.

Yes, you can use the procedure outlined in this stability testing post. Those numbers/letters indicate temperatures. Those are the storage conditions you are supposed to keep your samples at for various periods of time.

RT = Room Temperature
40C = 40 degrees Centigrade

By: nina

nina — Fri, 13 Apr 2012 19:21:50 +0000

Perry,
I was contacted by whole foods regarding my body scrubs they are interested in carrying in their stores. They have asked me to provide them with stability tests of my scrubs. Would I be able to use the one that you discuss above? Any other suggestions? Also, what does RT, 40C, etc…stand for??

Thanks for your help,

Nina

By: Maria

Maria — Fri, 13 Apr 2012 15:10:23 +0000

Thanks, Perry. I know that test need to be done at the start of studies but I was not sure how far or how often to do it. Now I know. Thanks again.

By: Perry

Perry — Fri, 13 Apr 2012 14:05:05 +0000

Thanks Nina! Very helpful.

By: Perry

Perry — Fri, 13 Apr 2012 14:04:37 +0000

Micro challenge testing should be done right at the start, then again on a sample that has been stored for 8 weeks at 45C. If it holds up to those conditions you can feel pretty confident in stability.

By: Maria

Maria — Fri, 13 Apr 2012 04:10:33 +0000

Hi Perry,
How often do we do microbiological testing and for how long do we need to do it when conducting stability studies of cosmetics, lotions in particular?

Thanks a lot. You’ve been very helpful.

By: Governmental Guidelines for Cosmetic Stability Testing

Governmental Guidelines for Cosmetic Stability Testing — Wed, 11 Apr 2012 11:20:40 +0000

[...] organization COLIPA issued some Guidelines on Stability Testing. We have previously written about cosmetic stability testing which was strictly based on experience. Let’s see how our stability advice stacks [...]

By: Nina Caisido

Nina Caisido — Tue, 10 Apr 2012 09:57:35 +0000

I would like to share the Q-rule, on my understanding, it can be applied to cosmetics as well. A sample computation will be: when product is stored at 45°C at 3 months, T = 27 months @ 25°C, so if you want to change the storage condition or temperature, just use the formula T = t x (Q10)n .. you may want to check the link http://www.clinchem.org/content/37/3/398.full.pdf for a detailed explanation..

By: Fleury Mathias

Fleury Mathias — Tue, 10 Apr 2012 08:08:56 +0000

It is also noticeable that commercially available instruments enable the determination of cosmetics stability in a shorter time period, thanks to optical measurement (Multiple Light Scattering for instance), such as the Turbiscan (Formulaction).