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Stable Hydroquinone Cream formulation.
I’m having troubles at making a stable hydroquinone cream. I used sodium meta-bi-sulphite and ascorbic acid and also maintained the pH around 5-5.5. can any one suggest me anything how to make a stable hydroquinon cream.
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19 Replies
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Not likely because it is a banned ingredient in most countries.
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in what way is it unstable?
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Just to add clarification, Hydroquinone is not banned in the US. It is a monograph ingredient however so you have to follow the FDA monograph guidelines.
It’s also not technically banned in the EU. It’s just that it is a drug product that requires a prescription.
As @Bill_Toge said, we’d need to know how your current product is unstable.
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Sorry to assume it was a cosmetic.
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Bill_Toge , it discolors after 2-3 days. I need to preserve the formulation for at least 1 and 1/2 yrs.
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What colour change did you notice?
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@Mamun chances are the ascorbic acid is the culprit here; something like sodium erythorbate will do the same job with less discoloration
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Belassi it changes to reddish brown and ultimately black .
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Bill_Toge can u plz explain why ascorbic is responsible for discoloration? any other ingredient instead of sodium erythorbate?
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Ascorbic acid is not stable and it changes the color to yellow-orange, by transforming in L-Threonic and oxalic acid.
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@em88 i agree as i saw the problem before any posts but waited to be sure the instability was due to color change.
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You are using actual ascorbic acid rather than one of its more complex derivatives? If so, I don’t think you will ever get acceptable stability.
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I think MAP would be the best choice as ascorbyl glucoside/ etc will react with semiquinone radicals formed from hydroquinone.
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Dr. Bob… is it due to the effect of pH of the media on ascorbic acid? as far as I know in the pH range of 1.0–4.4, the decomposition rate of ascorbic acid increases, while at pH 5.4–7.2, it decreases. due to alkaline pH, hydroquinone rapidly oxidized,tht’s why I kept the pH of the emulsion at 5-5.5.
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The ascorbic acid is unstable below 7 and discolors.Rate is likely Ph dependent.I would use MAP at the the current Ph of the system:should not discolor.____https://www.sciencedirect.com/science/article/pii/S0731708596019048
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@Belassi
I can understand why one would prefer ascorbic acid over stabilized forms:
http://thebeautybrains.com/2014/05/which-kind-of-vitamin-c-is-best-for-skin-the-beauty-brains-show-episode-31/
And it is stable in anhydrous systems (the brand CSI has 12% LAA + 98% butylene glycol). -
Try sodium Metabisulphite It makes cream whiter.
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I’m a year late, I see.
I work with HQ a lot. I include sodium sulfite at 0.1% and keep pH between 6.3 - 6.7. Never had a problem.
If you decide to stick to including Vit. C, you’re better off choosing one of it’s more stable forms such as MAP -
teewaya said:I’m a year late, I see.
I work with HQ a lot. I include sodium sulfite at 0.1% and keep pH between 6.3 - 6.7. Never had a problem.
If you decide to stick to including Vit. C, you’re better off choosing one of it’s more stable forms such as MAPCan you please recommend me a stable formula
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