I'm going through the same question right now. I start on ox next week and I need to figure this out. It's hard to get an accurate dosage if you use caps. First of all you need a scale that will read down to at least 10mg. That will cost you upwards of 100 bucks. The only other way to cap it is to add a known quantity of filler and try to shake it all together, but that doesn't ensure an accurate dose.
Oxandrolone is soluble in water, propylene glycol, and ethanol. I've read that it breaks down when suspended in water, so that's not really a good idea because it will begin losing potency. Propylene glycol tastes like absolute shit. They use it in the "safe" antifreeze to stop kids and pets from drinking it. Ethanol sounds pretty easy, but I don't know if it breaks down in that or not. If it doesn't break down in ethanol, then that's the route I'm taking. Just go to the liquor store and get some everclear.