[kbarb]

I have a recipe for a medical ointment calling for five ingredients, one of which is Silica Gel - Type H.
I'm thinking the silica gel is supposed to absorb excess moisture perhaps.

But what is the "Type H" designation ?
Is that different than what you get in the desiccant packets ? I would think so, as how could you mix beads into an ointment recipe.

(Also, anyone know what Type H silica gel is typically used for ?

Thanks,

Kent

[Stepan]

I might be wrong, but I believe type H is SiO2 with Al2O3. This is different than the one in desiccant package.  Silica gel in ointment can be a neutral additive to add volume and texture to the product. Some times it may contain bound ingredients (let say enzymes) , to provide prolonged (controlled) release.

[kbarb]

Ok, that's what I thought too. I only found one link to that so I wasn't sure - especially as to what it might be used for.
http://www.asianproducts.com/product/A11932137843700417_P12351226553267709/silica-alumina-gel-%28type.html

Also I wasn't sure what the molecule was, for the typical silica gel that's in the desiccant packets.

But thanks for your explanation - that helps.

[kbarb]

I figured it out . . . .
The type I was looking for is called micronized Silica (gel), used as a pharmaceutical excipient (non active ingredient.)

Grace  has SYLOID® 244FP silica and SYLOID 244 - about 2-4 micron size
http://www.grace.com/engineeredmaterials/productsandapplications/pharmaceuticalspersonalcare/CosmeticsApplication/FeaturesAndBenefits.aspx

To figure it out I asked a compounding pharmacist. He kind of laughed when I asked if it was the same as the little desicant silica gel packets.   ;-)