Preservative query for pH 7 cream
I’m using Carbopol 940 and I hope to use it at around pH 7 to really make the most of its viscosity potential instead of using more of it at a lower pH. I’ve found that Spectrastat OEL (caprylhydroxamic acid, ethylhexylglycerin, propanediol, caprylyl glycol) seems to fit in nicely with my desired product pH. I saw a comment from Perry indicating that a mixture of caprylhydroxamic acid, glycerin and caprylyl glycol (I think?) is quite a weak preservative system, so I thought, I could add phenoxyethanol to Spectratstat OEL and see where that gets me. Alternatively, I could just use Phenoxyethanol+Ethylhexylglycerin and a chelating agent like Disodium EDTA. My formula so far is as follows:
Glyceryl Stearate + PEG-100 Stearate: 3%
Peach kernel oil: 3%
Gosulin IL (Isoamyl Laurate+Isoamyl Cocoate):5%
Disodium EDTA: 0.2%
Shea butter: 1%
Alternatively I could use the Spectrastat blended with phenoxyethanol, or the phenoxy.+EHG alone. If using Carbopol 940 at higher than 0.3% will not give me an oily/sticky feel like Sepimax ZEN does between 0.3-0.5%, then I do not mind using more Carbopol 940.
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