[weezer96]

Hey! This is my first post, so thanks for taking the time to help me out. I really appreciate it.

I need to mix two powders accurately to be put into capsules. There will be 24 capsules in each "set" and each needs to contain roughly 2.6mg of powder 1 with around .2mg leeway. Powder 2 is a filler to fill up the capsules.

Powder 1 has a density of 1.389 g/cm3
Powder 2 has a density of 1.3 g/cm3

I understand the mathematics and procedure behind actually weighing, dosing, and filling the capsules. My concern, which is why I'm posting on a chemistry specific forum, is that will the small difference in density create "hot spots" of powder 1 in my solution when I mix them? I can not have one capsule with .2mg of powder 1 and another with 2.5mg.

Each "set" contains 24 capsules, so 62.4mg of powder 1 per batch. Each capsule holds much more than the 2.6mg of powder 1, so I have to fill it with another powder. My question is, when mixing the 62.4mg of powder 1 and the higher amount of powder 2, will they be precisely mixed enough to assume each capsule will contain roughly 2.6mg of powder 1?

I know I can not truly make a homogeneous mixture. I am afraid that after I mix the powder, they will separate as I go to fill the capsules. Will this minuscule difference in density cause this to happen?

Thanks

[Borek]

Powders don't separate automatically like liquids do (unless fluidized), so if you mix them thoroughly the composition of the mixture should be stable.

That being said I doubt dose will be identical in each capsule, I am sure there will be some minute differences.

[Squad]

Sorry for a late reply, just found these forums.

I would utilize something called 'geometric dilution'. Just google it up or look on youtube. It's a decent way for you to get a homogeneous mixture of your powders. When capsuling you should be fine and notice a uniform assay.

This is time consuming, but should definitely get you the results you need.

[Darryl1]

One part of my job is blending powder ingredients on a lab scale, the upping it to a few thousand pounds.  Generally the size of the particles seems matter more with the ingredients I'm using.  That said, sometimes just blending a little bit of oil into the mixture seems to cause the particles to stick more to each other and mix a little more uniformly.  Sometimes even just 1/2% is all that is needed.

-d