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Author: Subject: Lidocaine HCl synthesis

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[*] posted on 21-4-2017 at 05:18
Lidocaine HCl synthesis

I recently got a hold of some lab grade Lidocaine powder, and was going to try to make Lidocaine HCl. So I simply have to perform this reaction, I will also add I am using lab grade HCl.

C14H22N2O + HCl -> C14H23ClN2O

There will likely be some leftover acid, so I will wash with distilled water and neutralize with sodium bicarbonate solution, which will leave me with water, lidocaine HCl, and a small amount of contaminant NaCl.

I am very new to organic chemistry so I have a few questions about this reaction.

1. What type of reaction is this? is it exothermic/endothermic? Would I need to perform it under any specific temperature conditions?

2. Is there a reason I would not want to add the lidocaine directly to the HCl in a 1:1 ratio? Would the lidocaine need to be in some sort of solution?

My goal is to make medical grade lidocaine HCl that could be safely injected as a local anesthetic. Thank you for your assistance.
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International Hazard

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[*] posted on 21-4-2017 at 06:40

1. Exothermic. Thermal controls will only be necessary of you're making a whole lot with very concentrated solutions. Don't worry about it.

2. You need to combine them in a 1:1 molar ratio. Make sure you know what that means. Pure lidocaine freebase has low solubility in water and the reaction will be a big mess if you try to directly combine the two.

I recommend making a solution of the lidocaine in a low-boiling nonpolar solvent like dichloromethane, chloroform, or petroleum ether. Gas this solution with HCl and the lidocaine HCl will fall out of the solution as filterable crystals, which will dry quickly after filtration as the solvent evaporates. Recrystallize from water.

If you aren't experienced enough to make dry HCl gas, you can add your aqueous HCl to the lidocaine/solvent solution with lots of stirring, and then collect the aqueous layer which will contain the dissolved lidocaine HCl. Dry and recrystallize from water.

3. If you're looking to make it "safely injectable" I recommend starting with better than lab-grade HCl, which may contain traces of heavy metals. Make sure you understand exactly what impurities your reagents contain, and make absolutely certain you understand how to isolate the lidocaine HCl from the reactants and solvents used in this procedure. After you have prepared the product, I highly recommend a GC/MS run to verify there isn't anything other than lidocaine in any significant amount.

Make absolutely certain you are confident in preparing a sterile, isotonic solution of NaCl and lidocaine for the injection. IIRC it's usually something like 5-20mg/mL lidocaine plus a balance of sodium chloride to keep the osmotic pressure of the solution equal to that of blood. You'll probably also need to include a pH buffer and a preservative if the solution is to be stored.

Please be aware that botching any of this could have serious, if not deadly health consequences. Be aware that lidocaine is also an intravenous antiarrhythmic in addition to a local anesthetic.

[Edited on 21-4-2017 by Praxichys]

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International Hazard

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[*] posted on 21-4-2017 at 15:45

this is one of those if you have to ask a public forum you shouldn't be messing with it situations IMO
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[*] posted on 22-4-2017 at 01:31

Quote: Originally posted by tox662  
My goal is to make medical grade lidocaine HCl that could be safely injected as a local anesthetic. Thank you for your assistance.

You do know that it is illegal to prepare medicines for internal use by a process not approved by a regulatory agency? There are laws about this in just about any country. Even if you followed an approved process, it is obvious from your post that you do not have access to the required validated analytical methods. Not that we care about you breaking the law, but this laws are there for a rational reason of public safety that I agree with when it is about preparing sterile injectables (not to mention that injecting local anesthetics can cause serious complications if they get dispersed into the vascular system).

Anyway, since you are completely clueless about what you are doing, and even ask for advices on a forum for something that may result in a suicide, I'm detritusing this thread, so that nobody can be held responsible for your irresponsible acts.

…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)

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