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Remedies For stability problems of emulsions
Posted by myalcin on August 22, 2017 at 1:40 pmI have some questions about
Stability problems of emulsions.We have an intensive cream formulation. We have produced this formulation for many years. Some times we met some problems like that after packaging the water occurred in the package after a few days. But we couldn t see this problem first step . We do centrifuge test 5000 rpm 50 C 30 min. Although there is no problem when we do this test. We squeeze this product from the tube nearly after 2 months. We see water drops… we use protegin wx as you know this raw material is a mix oil phase that includes emollients, waxes and emulgators. So hlb balance must be correct. Why does the water drops occurre? How can we solve this problem? Could the cause of the problem the new generation preservatives?
Regards,
M.Yalcin
em88 replied 6 years, 10 months ago 7 Members · 26 Replies 
26 Replies

you describe syneresis or perhaps an unstable emulsion:if the latter is true you may need polymeric emulsifier.What is Ph and viscosity of cream?

Hi, thank you for your interest. We use the cream base from evonik; protegin wx which include petrolatum, ozokerite, hydrogenated castor oil, glyceryl ısostearate, polyglyceryl3 oleate. Our cream spekts; pH is 5,56,5 and viscosity is 80.000120.000.

You can add 0.1% Ultrez 10 to water phase and neutralize with 0.1% TEA after forming emulsion.it will add to viscosity but you are already at about 100K should not be too viscous and add to spreadability. test at 50C weekly for 4 weeks for stability.

Protegin WX is highly process dependent to get a stable product. Read the product literature as Evonik provides great documentation. As I recall, you do need to homogenize it several time (23) for several minutes as the bulk cools or you will have this problem.

Thanks for your interest. We use homegenizer 2 or 3 times for several minutes during cooling. We read the Evonik’s document. Although our formula and process is same with the documentation, we have this problem. Can we save this finished product or is it a waste? 
Hi Dr.bob,
Could you see above photo. We met this problem sometimes. Can we save this finished product by applying something or is it waste? If we can save how can we do? And Your suggestion adding ultrez 1, can it be solved our problem? Sometimes our viskosity value arrives 130.000150.000. I thing our problem is not viskosity problem for stabilitiy. 
Now after seeing photo, you have phase separation and if batch is already madetake sample 400 grams to lab and heat up to emulsification temperature—split in two after reaching temp—to 1/2 add 0.2% ULTREZ 10 and cool to about 50 add 0.2% Triethanolamineto second half at emulsification temperature add 0.5% Simugel INS 100 cool down no neutralization needed homogenize both and save a control untreated and test at 50C for 12 weeks. https://www.ulprospector.com/documents/1174263.pdf?bs=1432&b=65720&st=1&r=na&ind=personalcare

It looks like you are asking if your filled finished products can be reemulsified (“saved”) after phase separation in the tube. The answer to that is a definite “No”.

The suggestion above applies to bulk unfinished/unfilled product! If all is packaged its waste!

@myalcin in which case, there’s a high chance it’s destabilising as it cools; the solubility of the emulsifier(s) in water reduces as the product cools, which in drastic cases can lead to the water phase becoming physically detached from the interface
my first suggestion would be to find the drop point of the oil phase, and form the emulsion 510°C above that instead of at 80°C

Hi Dr.Bob,
There is also interesting thing. We tested this product as a bulk. We measured its viscosity value, pH, etc. And did centrifuge test at 3000 rpm, 50 C 30 min. the product passed all if these tests. And we filled it but after 56 months it would be like that How can we understand this problem before filling. 
myalcin Hi—it is time/temp dependent so you have to put at 50C for at least 4 weeks and monitor weekly;you should see it within two weeks at 50C,Centrifuge is only a short term indication and we would never market a product without doing the 50C for four weeks:you can also do 38C for three months and monitor monthly.It has never failed me with these types of products.

Freeze thaw should be conducted automatically as an early indication of stability before continuing the development process

But freeze thraw test is too long. If we apply this test as three cycle at our control system we should have wait six days before transportation. We do this test at first time for controlling formulary stability. And the formulary passed it. We have problems at continuous production

OK so the formula is freeze/thaw stable and if it were time/temp stable initially you shouldn’t have this problem with the formula unless you changed the process in scale up so as i said above the formula is basically time/temp unstable.

Hi Dr.Bob,
Yes the formula is stable we know that. Because it passed from all of the stability tests(long time like 3 monts etc.) and yes I think we have problem at the process some times. Ok I wonder which fast quality control test method we must do after every batch in the production for finding this problem? Freeze/thraw test is too long. (six days) wait 10C 24 hours and wait normal room temp 2025C 24 hours. This cycle must be 3 times for correct result. Can we do this test like that for one period wait 10C 12 hours and then 2025°C 12 hours? or how can we find if there is the stability problem on my batch or not? Which another method is more quickly then this test? Thank you for your interesting. 
@DRBOB@VERDIENT.BIZ if the temp is 50 Celsius for 4 weeks, what about RH%?

Unless there is a special condition we use ambient RH

@drbob@verdient.biz Hi Dr.Bob,
Yes the formula is stable we know that. Because it passed from all of the stability tests(long time like 3 monts etc.) and yes I think we have problem at the process some times. Ok I wonder which fast quality control test method we must do after every batch in the production for finding this problem? Freeze/thraw test is too long. (six days) wait 10C 24 hours and wait normal room temp 2025C 24 hours. This cycle must be 3 times for correct result. Can we do this test like that for one period wait 10C 12 hours and then 2025°C 12 hours? or how can we find if there is the stability problem on my batch or not? Which another method is more quickly then this test? Thank you for your interesting. 
I think you should develop your own test but freeze/ is not the way.You know that centrifuging at 5000 rpm for 30 minutes gives you a shelf life of about six months.What happens after 60 minutes? Actually what is time/temperature relationship between separation in ambient temperature/time and time required centrifuging required to get a two year shelf life?

This is a scaleup issue. The best thing to do is to find out what is different between plant production and lab production, then change how the product is made in the plant.
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