em88
Forum Replies Created
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Sls powder is so irritating, why don’t you avoid it? Use an already dissolved Sls instead
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“Polysorbates suppress foam.”
Is it noticeable even for low concentrations like 2%?
Thank you -
I’d suggest 5-10% urea.
As you said, urea will degradate and increase the pH. You will need a buffer to maintain urea stable. -
Isn’t pharmacovigilance to report problems / side effect for a product?
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I have to create an acidic solution with the pH 2-3 to dissolve the API and than to neutralize at the end. The product is a shampoo.
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eucalyptol may separate. You should add tween 60 as well.
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I was thinking to use citric acid instead of HCl, but it needs a lot of NaOH/TEA to neutralize at the end.
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AISI 316L is the best for sure, but it has its weak points.
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We used once HCl solution on 316L stainless steel and it left marks quickly.
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Thank you for your reply.
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ALS and ALES are better in foaming and cause less irritation than SLS and SLES.
The problem with the ammonium surfactants (as far as I know) is stability, they are less stable than sodium in a wider pH range. Also ALS seems to damage the stainless steel. -
I thought BHT was very soluble in ethanol. I should recheck this.
I guess, 60 C heated for a short time should be ok. -
I have worked with BHA, which was used for a shampoo.
We add BHA at 40 C, at the end of the process. We use temperature just to speed up the solubility, after that the process is continued at RT.
What if you dissolve it in ethanol and add it at the end? -
Ammonium LES foams better than sodium LES. I’m waiting to put my hand on magnesium LES as the manufacturer says (they have made tests) it is one of the best and the best compared to ammonium and sodium.
If SLS and SLES are liquids, their concentration is most likely to be around 30%. -
Yes, a degradation should happen, reducing its function.
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Tween will increase the dispersion of ZnO, in emulsion, suspensions, oinments, but if water is present, ZnO should form Zn(OH)2 which is easily dispersible in water. So tween is not so necessary for ZnO
ZnO and talc should reduce rush, but the concentration should be over 5%, enough to form a film over the affected skin. -
According to handbook of pharmaceutical excipients, up to 3% as preservative.
I have seen formulations with 2% several times -
What about polysorbate 80? 0.5-2% should increase the stability of the suspension and facilitate the redispersion.
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You should observe an increase of viscosity when adding citric acid to get the pH 5. Try to keep the pH around 6.5-7
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Do the salt curve up to 2% and check what’s the maximum viscosity you can get. If not enough, you may use proper thickener like gums, cellulose derivatives, polymers etc,
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Ingredients?
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@Bill_Toge, I agree with you. It is very flammable, and needs a lot of caution. But is the best one (from what I know) to for clear alcohol gels.
Boots uses pyroxylin in they Bazuka gel line products. I’ve seen other manufacturers as well.@Belassi, there is a huge list of the same rubbish added in shampoos, what about that?
Calcium acetate should form gel in ethanol as well
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It is flammable but not an explosive like nitroglycerin is.
The exact type of nitrocellulose I’m talking about is pyroxylin. -
You are confusing nitroglycerin with nitrocellulose 🙂
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I’m confused with citric acid used to adjust the pH to 7. Also why pH 7?
You should add glycerin, it should increase the viscosity by little.
Nitrocellulose will create gels with alcohol.
You may try HEC but with that much alcohol, it may precipitate.