[em88]

Ignore my last question. I did a research and found out that the lactic buffer isn’t very suitable, while the citric buffer has better ranges. 

[em88]

Yes, I’ve red that and was going to try (it’s a great idea), but currently I don’t have LA to make the buffer and it will take some time till I receive it, can I use an other buffer? For example phosphate?

[em88]

Hello,
I have to at last to increase the pH to at last 4.5…
I found an other cream in the local market. They use urea 15%, lactic acid (not specified the % and salicylic acid as preservative (most likely 0.5%). None of the ingredient mentioned on the box should increase the pH, still the pH is 7.4
Petrolatum, aqua, urea (15%), glycerin, plant extract, cetyl alcohol, plant etract, lanolin, glyceryl stearate, plant extract, paraffinum liquidum, lactic acid, salicylic acid. The ingredient are written from the highest % to the lowest. 
Any thought?

[em88]

Is it reasonable to think that starting from a formulation with 1% SA and 1.25% TEA, the pH increased from 5.5 to 7.9-8 and remained at this level, that by making the following change, 1.5% SA and 1% TEA the pH should be around 6-7? Or can I go straight to 2% SA and 1% TEA and still have a pH over 5? 

[em88]

The only issue with alcohol would be that it dries the skin, other than that it should be ok…

[em88]

@johnb, I know, I have just mentioned where is the cosmetic going to be pointed. Obvious it will be described as a cosmetic. Thank you!
@chemicalmatt, I can add SalAcid up to 2% and reduce TEA to try to atchive pH 5 (I guess), can you please be more specific regarding the lactate buffer?
I have added glycerin to lower the water, do you think propylene glycol would do better than glycerin?
Unfortunately I’m not sure I can lower the urea to 5%. Thank you!
 @DRBOB@VERDIENT.BIZ, did your product have urea? Thank you!

[em88]

Hyperkeratosis dermatitis, follicular hyperkeratosis, ichthyosis, psoriasis, acne etc I’ll need both the keratolytic and emollient effect. I know that the gel you prepared is for warts removal, I asked because I may have to make a gel formulation with 10% salicylic acid too and was curious how did you manage to dissolve the salicylic acid since 1g needs around 500g water to dissolve also you did not have alcohol in the formulation which would dissolve the acid much easier. I noticed now from my tests that the increase of pH was due to TEA acting very slow. I will try to find the ration of TEA and acid to maintain the pH within 4.5-8 were urea is stable.

[em88]

Unfortunately I can’t remove urea and it has to be at 10% level. This ingredient is well known as “good” active ingredient for skin conditioning by patients that’s why is highly requested. While salicylic acid should be at higher level (as you suggested at 10%), but for concentrations of over 2% the cream can only be registered as drug and not as cosmetic cream. 
Was your salicylic acid gel transparent at the end or it got a whitish color? How did you manage to dissolve salicylic acid? 
I’m sorry am asking you so many questions, but I’m kind of new in semisolid formulation, I’ve worked only with solid drugs.

[em88]

The formulation you have worked was based more on the keratolytic effect, urea at 3% doesn’t do anything extraordinary to the skin.
I haven’t considered a formulation for gel containing these two active ingredients, I would assume, if I get the same results of stability, the gel would be bubbly. In any case, I will try a formulation and see where it goes.  Thanks for the kind and help!

Have a look at this patent. https://www.google.com/patents/WO2006102004A2?cl=en They do provide some formulations using NaOH. Also I have seen some other creams (last one was on amazon) containing TEA.
Urea is such a pain to work with. I’ve noticed after unsealing the cream (from one of my earlier formulations) stored in tubes, the cream will get outside by itself proving an increase of pressure inside the tube which is caused most likely by CO2. 

[em88]

One more question, what was the pH of the gel?

[em88]

Your formulations seems to be far more better than mine, would you mind giving a few more details? Also what was the percentage of lactic acid and salicylic acid?

I’ve read several articles claiming that urea decomposes with releasing CO2, especially in presence of water, acid pH (less than 4) and at higher temperatures. So I tried to avid all these incompatibilities. I agree with you regarding the concept of the formulation, that is why I am asking for help.
Here is the current formulation

Cetearyl Alcohol

Petrolatum

Paraffinum Liquidum

Polysorbate 80

Sorbitan oleate

Cetyl palmitate

Isopropyl myristate

Triethanolamine

Ethilic alcool

Glycerin - 20%

Salicylic acid

Urea

Purified water - 25%

Thank you

[em88]

Indeed its purpose is to be keratolytic. 
First formulations were without TEA, but after a few hours the cream had a “cheese” appearance due to CO2 release. 
Did the cream you prepared remain at the same consistency? Also why did you add propylene glycol?
Thank you

[em88]

Hello,
Thank you for your replies. The other ingredient is salicylic acid.
So with the current formulation, I adjusted the pH from around 3.5 to 5.5-6 with triethanolamine (2%). What I’ve noticed recently is that the pH after a few days will increase to 8-8.2. This worries me about the urea’s stability.