If you do not know the pharmacokinetic parameters of the agent, I would agree with Luis. Only thing to keep in mind is that the infusion pump will continuously infuse some of the drug over a period of time. If you want to reach a desired concentration immediately, a single epidural injection would work.
Thanks, all. I will have to do some thinking as to how best to approach this based on your suggestions. The osmotic pump may be useful, as I am looking for a mechanistic effect of a treatment that may influence this pathway.