[Abdullah]

@Paprik it is already in solution of 30% Amodimethicone. Should i solubilize it in what? 

[Abdullah]

@Pharma what about lactic acid? 

Whith which acid instead of citric acid most of salicylic acid would be in acid form? 

[Abdullah]

you can try konjac with xanthan gum. They have good synergy for viscosity. 

[Abdullah]

@Pharma i have done it and it is stable. Increase the pH with sodium hydroxide did solubilize salicylic acid in water. The ph was high about 7 so i reduced the pH with citric acid back to 3. Now i am not sure if it is in acid form or salt form in pH 3. Any idea?

[Abdullah]

Pharma said:

Theoretically, you’re correct (I didn’t do the maths but I sounds about right).

The ‘problem’ with larger quantities is:

Add ‘active acid’ -> increase pH with strong base = part ‘active acid’ & part ‘active salt’

Add ‘active salt’ -> lower pH with strong acid = part ‘active acid’ & part ‘active salt’ & part salt

Add ‘active salt’ -> lower pH with weak acid = part ‘active acid’ & part ‘active salt’ & part acid & part salt

is this part acid, citric acid in example of reducing pH of sodium lactate with citric acid?

Thanks ????
 What about salicylic acid?
If we add 0.29% sodium hydroxide to 1% salicylic acid in water,it solubilizes it but the pH is about 7. If we then reduce the pH with citric acid or lactic acid to 2.9 or 3, would there be about 50% of salicylic acid in acid form? Forgot about inactive acid or salt. 

[Abdullah]

@Pharma yes but my point is about percentage in any quantity.

For example
If we take two formulas that are the same, add 0.3% sodium benzoate in one formula and 0.3% benzoic acid in another formula, if we adjust the pH to 6, only 1.6% of preservative would be in acid form in both, and if we adjust the pH to 4, 61.3% of preservative would be in acid form. 
Am i correct in this?

If yes, it means the availability of benzoic acid or sodium benzoate in acid form depends on final pH, not the form you have added it. 

So why availability of lactic acid or salicylic acid in acid form is depended on the form you have added it and not the final pH? 

[Abdullah]

Pharma said:

Yes, 1 unit below pKb means 90% protonation, 2 units 99%, 3 units 99.9% and so on.

Thanks

[Abdullah]

@Pharma what is pkb?
And does 1 pH lower than pkb mean 90% protonation in everything? 

[Abdullah]

Reduce betaine and DEA to half. 

Although i don’t think you shampoo makes the hair dry

[Abdullah]

@Pharma i am using lactic acid. I just wanted to know if i reduce the pH of salt, does it function as acid or not.

Now if it is so, how does preservatives like sodium benzoate and potassium sorbate at low pH function as there acid? 

[Abdullah]

Thanks

[Abdullah]

@Pharma thanks ????

The pH would be about 4. Is 1 and 2 weak even at pH 4?

[Abdullah]

@Pharma on what ?????

For example if i use Stearamidopropyl Dimethylamine and Polyglyceryl 6 distearate as emulsifier in a lotion, which polymer would make it more stable?
1. Guar gum (non-ionic)

2. Guar Hydroxypropyltrimonium Chloride (cationic)

[Abdullah]

@Pharma in cationic surfactants, which one is weak and which one is strong?
1. Stearamidopropyl Dimethylamine
2. Behenamidopropyl dimethyltryptamine
3. Behentrimoniom cloride

4. BTMS

5. Distearyldimonium Chloride

And how do we know what is weak and what is strong ionic? 

[Abdullah]

@Pharma Just to check that i have understood correctly, of i use ionic+fatty alcohol+ non-ionic surfactants at 5% total, should i use 5-10% of this 5% which is 0.25-0.5% ionic, 0.25-0.5% non-ionic and 4-4.5% fatty alcohol? 

[Abdullah]

@Pharma i am using sodium stearoyl lactylate 0.8%+ glyceryl stearate 3.2% in another emulsion. That is a good product and economic that i really want it to be. The only drow back is that at pH below 5 SSL become grainy. 

I want to have one product at pH 4 and as i am using petrolatum and +10% glycerin, i want to have some cationic surfactant or whatever ingredient that can reduce the tackiness.
Also i am using Ethyl lauroyl arginate in that product which is cationic.

Do you have any suggestions for non-ionic polymer other than guar gum and cellulose? 

[Abdullah]

Also by large hydrophilic head groups, do you mean lower HLB? 

[Abdullah]

@Pharma thanks for explanation.

In one emulsion i use 1% Polyglyceryl 6 distearate+ 3% setearyl alcohol. Does setearyl alcohol count as co emulsifier? I mean should i add 0.1% or 0.4% ionic emulsifier to this to be like 10% total emulsifier?

I want to add cationic emulsifier to get that powdery feeling with stabilization. As they are expensive, the least expensive one i found is Stearamidopropyl Dimethylamine. Is this a good option to add in skin lotion for a boost of stability and that powdery feel of cationic surfactants? 

[Abdullah]

brettdrouin said:

Has anyone tried any of the Euxyl brand preservatives? Im using Euxyl k903 which has a combination of 

• Benzyl Alcohol            78.0 - 84.0%
• Benzoic Acid              11.0 - 13.0%
• Dehydroacetic Acid     6.5 -   7.5%

Trying to keep my products on the more natural side, but want to have a good broad-spectrum preservatice system. Ill be making a line of products from shampoo and conditioners to hair products like clays, pomades, grooming creams and hairsprays

I would use phenoxyethanol instead of benzyl alcohol.

[Abdullah]

@emma1985 that sounds good.
What is your product? 

[Abdullah]

Paprik said:

Abdullah said:

Paprik said:

I would say no, it is not ok. This would be no good GMP.

I guess you always open new barrel or packaging of a raw material and that’s where the issue could appear. 
It something goes wrong, it would be really hard to know what batch went wrong or so. Contamination, bad raw material etc … 

For surfactants kind of often but for preservatives and conditioners not so often as the quantity i purchase last longer.

Is the change and use of new package of raw materials the only concern or there could happen a problem for the small amount of product that stays in the wall of tank for one or two days?

I wish I had an answer for this. From common sense, the leftover material should be well preserved, so it should not be a problem.

A part of me wants to say it would be ok and I believe some companies would probably do it, but from good GMP, this shouldn’t be happening. 

Perhaps someone else will have something to say about this  

Thanks

[Abdullah]

@Perry hello 
I have a suggestion

I have learned a lot of things from this forum. I have asked every question i had about formulation here because i trust it more than any other source on internet and have good very good answers. Usually i review the discussion i have posted one a month. This way i learn more things, things that i didn’t understand enough when i had posted it. As the number of my discussions are a bit high, if i want to review for example all my discussions about one subject like preservative or shampoo or emulsion, i have to search all the discussion that are going to increase day by day.

my suggestion is if there be a feature to categorize the discussions we have posted or tag them for certain names or make folder for different categories like preservative or surfactant etc,  that would be very helpful for some one who want to review his questions evey now and then.

Thanks

[Abdullah]

ozgirl said:

I would agree that you you need to clean it after every batch.

I would look into buying a bigger tank because as you said you are wasting time and resources making small batches.

You could probably just make 1 x 1000kg batch a week. It would take a similar amount of time to make a 200kg batch as it would to make a 1000kg batch (maybe slightly longer if you need to heat the batch).

Yes that i a good option. But i wanted to know if there is anyway to eliminate this washing process at all.

[Abdullah]

Paprik said:

I would say no, it is not ok. This would be no good GMP.

I guess you always open new barrel or packaging of a raw material and that’s where the issue could appear. 
It something goes wrong, it would be really hard to know what batch went wrong or so. Contamination, bad raw material etc … 

For surfactants kind of often but for preservatives and conditioners not so often as the quantity i purchase last longer.

Is the change and use of new package of raw materials the only concern or there could happen a problem for the small amount of product that stays in the wall of tank for one or two days?

[Abdullah]

Thanks