I would suggest warming the Lipoderm, to aid in the dissolving of the RK, by placing the bottle in a hot but not scalding bowl of water for a few minutes before adding the powder.
Add a portion of the powder at a time, get a good dissolve before adding more.
If there is still residue left after mixing and shaking, you can add a small marble or ball bearing as a shaker aid into the bottle.
I don't know that RK is a difficult to dissolve powder, these are just general tips for most effective adding of ingredients into transdermal solutions.