I've recently started to cell a certain powder (DMAA) that's fully legal in my country. Right now, I'm selling it in bulk starting at 1 gram, which is quite easy to measure with a cheap calibrated scale.
But I also want to start selling the stuff in cellulose capsules. A commons dose of DMAA is 25mg, so there needs to be close that amount of it in the capsule. I've no problem with filling the capsules one by one, by hand. But the problem is, how am I going to measure out 25mg precisely and consistently? Scales with that accuracy (the on I have has 10mg precision but isn't very precise at the mg range) are not cheap and are not an investment I want to make right now. And even if I would buy a cheap model, those things react when you blow a little wind on them, which I don't think is a good thing.
So, I've been thinking and came up with something. The chemical DMAA (methylhexanamine, CAS no. 105-41-9) has a density of:
0.761g/mL (Yaws' Thermophysical Properties of Chemicals and Hydrocarbons (Electronic Edition));
0.7655g/mL (Yaws' Handbook of Physical Properties for Hydrocarbons and Chemicals));
The average of these four is 0,769g/mL. Let say I take that, and measure out 0.05mL of the powder using a 0.05mL scoop (like this one: ).
Would that yield me 38,4mg (0,769 / 20) of powder? I'm wondering this because I figured that a powder could have multiple densities depending on how it's stored (compression, humidity etc).
I also thought about using filler, but I've no clue of how to get a highly homogenous mixtures of the chemical and the filler.
Can anyone give me any pointers on my musings, or give some suggestions as to how I would go about measuring milligrams of powder?