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Re: Appropriate pH buffer
To all my amazing fellow formulators, especially those familiar with low pH formulation, I’ve got a bit of an issue:
I’ve created a serum that, among other ingredients,contain lactic acid and glycoic acid; by the end of formulation my pH averages around 2. I want to boost the pH to about 3.2 at room temperature.
I used NaOH 1:1 ratio with DI-water and it adjusts fine, but, there is an unappealing ammonia undertone by the end of it. Now, there is probably a way to use a fragance to mitigate that but current policy for this formulation is do not include any scenting ingredients.
We tried 1M solution of Sodium Citrate because we thought it might work, but, of course… DON’T ADD salt to lotions or leave ons… it was draggy, we needed more of it than we were comfortable adding into the formulation, it was a mess, and most importantly, it messed with the salt curve. This Sodium Citrate thing might have been a little desperate tbh.
So, basically I wanted your advice on a solid buffering chemical that does not have an ammonia type smell and doesn’t affect the salt curve of our lotion, preferably doesn’t use salt at all. We were thinking of using TEA 99% but that has a bit of an ammonia odor, so before we do anything and waste anymore resources, I wanted to ask you guys for your opinion of it all.
Thanks a lot for your help guys.
~ Mike
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3 Replies
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the easiest way to achieve the result you want is to reduce the level of acid, and/or use weaker acids
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@Bill_Toge, thanks a lot for your advice.
We’re using 4% lactic and 3% glycolic so I didn’t think it was that much, but, maybe it is. We wanted it for exfoliation purposes, of course, so I’m worried if we go much lower we won’t see much action there.
I know you’re being realistic, but, I was hoping I wouldn’t have to be, haha.
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I’m not sure what you mean by not adding salt, as any form of neutralization creates salt.
Sodium Lactate buffer may be of use. L-Arginine solution to neutralize - added benefit of skin moisturisation. Seems like an awfully high concentration of lactic/glycolic. Any idea what in your formula is creating the ammonia smell?
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