So I'm a hobbiest, no pro. I've got a formulation for a topical anesthetic I'm trying to mimic. It calls for lidocaine, ethoxydiglycol (aka. diethylene glycol monethyl ether) and a couple of oils. I've got Lidcaine HCL, and I've read that Lidocaine HCL is soluble in water, but not soluble in ether. Based on that, I'm concerned I won't be able to mix my Lidocaine HCL with the ethoxydiglycol. Similarly, I've read that Lidocaine base is soluble in ether, but not water. Since the formulation calls for ethoxydiglycol (aka. diethylene glycol monethyl ether), I assume what I need is Lidocaine base instead of the Lidocaine HCL I've got on hand.

To get around this. I'm planning to dissolve the Lidocaine HCL in distilled water, then add baking soda to it until the PH drops low enough for Lidocaine base to precipitate. After that, I plan to filter the whole thing through a coffee filter, rinse with more distilled water, then evaporate the water off. I'm hoping this will yield pure Lidocaine base that I can work with.

So, here are my questions:

  1. Will it work?
  2. Are their any caveats I should know about?

Thanks for your help!


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