Monday, May 10, 2010

Replicating Spectro-Jel for blemish prone skin

I think Spectro-Jel might be a Canadian only product, but it's been a very effective cleanser for my skin for years (until I started making my own - but I still take it on camping trips because it's a great no-water-necessary cleanser!) It's a lot like the Cetaphil cleanser we looked at the other day as it is supposed to be a non-surfactant (detergent) based cleanser for sensitive skin.

If you want to know more about the mechanics of duplicating products, click here or go back to yesterday's post!

Ingredients: Aqua, Butylene Glycol, Glycerin, Hydroxypropyl Methocellulose, Polysorbate 20, Cetyl Alcohol (moisturizer), Hydrated Silica, PEG-12 Dimethicone, Diazolidinyl Urea, Carbomer, Triethanolamine, Sorbitan Oleate.

Aqua (water): The solvent.

Butylene glycol: A humectant.

Glycerin: Again, a humectant.

Hydroxypropyl methocellulose: A thickener. This is a gel like product, so this makes it gel like!

Polysorbate 20: Our emulsifier (needed for the cetyl alcohol). Polysorbate 20 is generally used for small amounts of oils - like fragrance oils - so this gives us a clue to how much cetyl alcohol is in the product.

Cetyl alcohol: An oil free way to moisturizer.

Hydrated silica: It is used as an abrasive and exfoliating ingredient or used as a gelling agent if the particles are small enough. (Interestingly enough, dried silica is a dessicant, an ingredient that draws water out of the atmosphere to it - also known as a humectant. When you find silica in your computer or other electronic with the big "DO NOT EAT" warning, it's there to attract moisture to the package and leave the consumer electronic alone. The "do not eat" thing is weird...have you ever eaten something you found in your shoe?) Because I don't remember feeling any abrasives in this product, I'm thinking it's a gelling agent.

PEG-12 dimethicone: This is a water soluble dimethicone used for moisturizing and skin conditioning.

Diazolidinyl urea: The preservative, generally found in liquid Germall Plus.

Carbomer: This is another gelling ingredient. We've used it in this post as Ultrez 21 or ETD2020.

Triethanolamine: TEA, the ingredient that causes the carbomer to gel. (Read more about TEA here.)

Sorbitan oleate: This can perform many functions - it could be an emulsifier, a humectant, or a sweetener. As we already have a ton of humectants, and I'm not really planning to eat this, I'm concluding this is used as an emulsifier. Because it's a low HLB emulsifier - 4.3 - I'm thinking it's the co-emulsifier for the polysorbate 20 - HLB 16.7.

How to figure this one out? I know if I use 1% Ultrez 21 to make a gel, I need 1.5% TEA. I know this is a nicely gelled product, but not a thick one, so that's a good place to start. But TEA comes after the carbomer, which means either they're using less TEA than carbomer (which won't work) or this is the part of the ingredient list where the 1% can be put in any order. As the preservative is in this same area, I think it's safe to say that the ingredients from the preservative down aren't necessarily in strict amount order.

So I must be using less than 1% Ultrez 21 or a different kind of carbomer. Since all I have is Ultrez 21, I'll start with 0.5% Ultrez 21 and 0.75% TEA.

This doesn't sound like a lot, but the hydroxypropyl methylcellulose (which I'll be calling cellulose for the rest of this post because I can't type that much all the time!) will help make a really amazing gel at 0.3% to 1%. It can be used at up to 3%, but that'll make a really thick gel. So I'm thinking it's probably lower than that - say 1% or 2%. Combined with the Ultrez 21, 1% cellulose and 0.5% Ultrez 21 will make a medium weight gel suitable for cleansing your skin.

I don't have hydrated silica and don't know where to get it, so I'm working with these two gelling agents alone. 

So right now I have some great ideas on how to make this product. Since it's intended for blemish prone skin, we won't see a ton of dimethicone in there. I'm thinking 1% might be a good place to start. And the cetyl alcohol will be low, so I'm thinking 1% about that as well.

So we come to the emulsifiers - polysorbate 20 and sorbitan oleate are a high HLB-low HLB combination. You can use these as low as 2% in your product. Cetyl alcohol has an HLB of 15.5, so we need to figure out how much to use of these two ingredients. Polysorbate 20 is 16.7; sorbitan oleate is 4.3. To get to 15.5 (cetyl alcohol's required HLB), we could use 90% polysorbate 20 (15.03) and 10% sorbitan oleate (0.43) for a total of 15.46, which is pretty darn close to 15.5. So if we use 2% emulsifiers - which is enough for this application - we get 1.8% polysorbate 20 to 0.2% sorbitan oleate. Since the polysorbate 20 comes in at 1.8%, we'll use less cetyl alcohol (lower on the list) at 1.5%.

Since I don't have water soluble dimethicone, I'm using regular dimethicone at 1%. We have enough emulsifier to emulsify this at 2% polysorbate 20-sorbitan oleate. Oh, wait, I don't have sorbitan oleate, so I'll choose another low HLB value emulsifier. I could use glyceryl stearate (3.8), glycol stearate (2.9) or glycol distearate (1). If I go with glycol distearate, I have to use 93% polysorbate 20, and 7% glycol distearate, so 1.86% polysorbate 20 and 0.14% glycol distearate will emulsify our product.

So what about our glycerin and butylene glycol? Since I'm a little tired after all that math...I'll go with 5% each and see if I like it. I don't have butylene glycol - I have propylene glycol and hexylene glycol so I'll choose one of those. (As a note, prop- means 3, buty- means 4, hex- means 6, so they are similar products with different numbers of alcohol groups. They are mostly interchangeable for our purposes.) Propylene glycol is easier for me to get, so I'll go with 5% of that and 5% glycerin. Which means whatever's left over is the water amount.

So this is what I'm thinking about this duplication...
83.25% water
5% glycerin
5% propylene glycol
1.86% polysorbate 20
0.14% glycol distearate
0.5% liquid Germall Plus
0.5% Ultrez 21
0.75% TEA
2% hydroxypropyl methylcellulose
1% dimethicone

Wow, this seems like a lot of work for something I can buy for $12 ($9.99 on sale at times) for a giant bottle. But duplicating is its own reward, right?

Normally, I'd say yes. But this recipe will be a massive pain in the bum to duplicate. We have to make sure we get the gel right, then the addition of the emulsifiers to the gel, which can break it down pretty easily, then add the water and other ingredients. And, in the end, I've stopped using this regularly because I think it's actually contributing to a little atopic dermatitis on my skin thanks to the dimethicone (which my hair loves, but my facial skin hates). If you want to try this, go for it...but I'm a little tired now.

Why am I posting this recipe? One, to show you the process of duplication and how complicated it can get (ask me why I haven't tried to duplicate any facial moisturizers - the ingredient lists are insane). Duplicating is a theoretical exercise first, a formulating exercise second. We never know if we'll get it right, but it's a great way to learn what the different ingredients add to the mix so you can include other things or take out what you don't like. As little as 0.5% of one ingredient makes a huge difference (we see this with cetrimonium chloride at 2% - awesome!) so we can learn to tweak our own products well when we see the small amounts used by large companies.

Two, because we can learn from our mistakes. I think you could make this recipe, but I've learned that I really don't want to make it. It's a lot of work and I have other things I want to make instead. And three, I spent about two hours researching and writing this rather than eating breakfast and taking a shower, and I don't want that hard work to go to waste.

If you try this, please share your results! I'd love to see how it works out!

1 comment:

Jaslyn Begni said...

Very insightful approach on duplicating products. I think after all the HLB calculations you forgot to add the 1.5% Cetyl Alcohol to your formulation... am I wrong? You must have been really tired. I would love to try this but don't have a low HLB emulsifier, maybe next month's budget. Thank you