• Neuroscience & Pharmacology Discussion Welcome Guest
    Posting Rules Bluelight Rules
    Recent Journal Articles Chemistry Mega-Thread
    FREE Chemistry Databases! Self-Education Guide

  • N&PD Moderators: Skorpio

Extracting the active compound from slow release tabs

C

CrimpJiggler

Bluelighter
Joined
Aug 28, 2011
Messages
241
I'm trying to come up with a way to isolate a highly water soluble active compound from slow release tablets. To override the slow release mechanism all you have to do is powderise the tablet(s) and let the powder soak in water for a few hours. Powderising will increase the surface area of the active compound like mad so all of the drug will get dissolved and leave behind the insoluble crap they use for the slow release mechanism. Ordinarily to separate a soluble compound from insoluble crap all you'd do is filter but the problem here is one of these excipients is a gelling agent (hydroxyethyl cellulose) and another one is a surfactant/emulsifying agent (cetostearyl alcohol). These are the only 2 uncommon excipients in there so I'm positive that one or both of these excipients is responsible for the slow release mechanism. What I'm wondering though is will these excipients be a problem for extraction attempts cuz they fuck with the solubilities of all the compounds they're mixed with.

To deal with cetostearyl alcohol I'm thinking there must be some tricks for separating surfactants from solutions. Anyone here know any tricks for this?
 
sekio said:
Acid/base extraction, it's not rocket science.
Click to expand...

He mentioned surfactants in his original post. Those really give ANY extraction hell because the whole purpose of a surfactant is to disrupt the interface between polar/nonpolar systems. It turns the extraction into one big emulsion.

I've had problems doing an extraction before because of trace amounts of detergent left on the glassware. I was unable to fix the problem and save that batch of what I was working on, so I don't really have any helpful advice to offer.
 
Cetostearyl alcohol is a wimpy emulsifier, it's a simple fatty alcohol. Not like it's SLS or anything.

Another option: centrifuges. Those would be great at getting pill sediment/gelling agents out.
 
Crush pills in blender
Filter
Add phosphoric acid until pH=1.5 (hopefully your compound is acid stable). Hydroxyethylcellulose will be cleaved in a few hours with stirring and gentle heating
And then, if you have an amine (probably), run through a cation exchange column washing with pH=6 or 7 solutions to get rid of the detergent, then elute with a basic solution. It'd be easier with an ionic detergent, maybe adding something like DMSO or urea to the wash solution would help get rid of the long chain alcohols but it may also destroy the column matrix
 
scureto1 said:
He mentioned surfactants in his original post. Those really give ANY extraction hell because the whole purpose of a surfactant is to disrupt the interface between polar/nonpolar systems. It turns the extraction into one big emulsion.

I've had problems doing an extraction before because of trace amounts of detergent left on the glassware. I was unable to fix the problem and save that batch of what I was working on, so I don't really have any helpful advice to offer.
Click to expand...

Yep. Surfactants really complicate matters. They have unique properties that one might be able to exploit though. For example when they reach a certain concentration (the critical micelle concentration) they aggregate together and form micelles and a solution of micelles has different properties to a solution of free surfactants. Acid would probably hydrolyse the hydroxyethylcellulose but the real surfactant in there is cetyl alcohol. Its a fatty alcohol so you could disable its surfactant properties by acetylating it but in this case, I'd end up acetylating the API.
 
You must log in or register to reply here.
Top