RogueRose
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Equipment that can analyze API concentration of medications?
I am curious if there is equipment that has the capability to VERY accurately analyze and detect the exact percentage/amount of active pharmaceutical
ingredients in medications. This question is not meant to be performed by the home/hobby chemist but by a certified professional lab - so I am
looking for what equipment would be needed to provide the most accurate results for testing wider ranges of medications, possibly complex compounded
meds (multiple API's and possibly soluble fillers).
Let's just use a standard hydrocodone tablet of 5/500 for example.
I'm not sure if chromatography can tell quantity in a sample but I think it will tell what the ingredients are, so it would detect spikes at APAP and
hydrocodone and some cellulose filler possibly - BUT - can it show that there is in fact exactly 5mg of hydro in the sample and 500mg of APAP?
I know there is gas and liquid chromatography but am not sure if one is more accurate or is better for certain substances.
On another note, if a pharmaceutical has a single water soluble ingredient, with the rest being something like talc or cellulose, how accurate would
a water extraction followed by .2um filtering (repeat process with a second washing) then vacuum evaporation, ending with weighing the sample be -
possibly testing ~250-400mg of API from multiple pills. Is there any reason to think that this type of testing would yield results CONSIDERABLY lower
(such as only 30% of API in resulting yield) than expected? The API is highly water soluble (200mg/ml) & 10 ml of DH2O was used for 2 separate
washing's followed by a 3ml flushing of the syringe filter. The resulting liquid was 22.7ml with an expected result of 300mg of API, yet only 87mg
being obtained. Other than the fact that the medications being severely under-dosed, is there any possible reasoning for such a major discrepancy of
API yield? Be assured that the extraction procedure was performed correctly (no spillage, lack of mixing, destruction by heat, etc) and that should
not be the focus of question other than possible adding a step(s) which would make this more accurate.
I would think that liquid extraction as described above would be one of the more accurate means of verifying API "dosing" if only one API per
medication. However when more than one API is involved per medication and if fillers like lactose or other water soluble fillers are involved, this
could be a cause for inaccurate results, hence my question about chromatography.
If anyone knows of the industries "best practices" for determining exact content of pharmaceuticals (and examined street drugs actually - that would
be interesting) please inform us as to what these are.
All helpful and constructive responses are greatly appreciated!
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tandpasta
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Afaik any decent HPLC setup can be used for quantitative analysis. I suspect that the most critical component in terms of measurement
precision/sensitivity is the chromatograph you attach to it.
"Almost any compound that can be retained by a column can be separated by
a column. HPLC separations have been achieved based on differences in
polarity, size, shape, charge, specific affinity for a site, stereo, and optical isomerism.
Columns exist to separate mixtures of small organic acid present in
the Krebs cycle to mixtures of macromolecules such as antibody proteins and
DNA restriction fragments. Fatty acids can be separated based on the number
of carbons atoms in the chains or a combination of carbon number and degree
of unsaturation. Electrochemical detectors exist that detect separations at the
picogram range for rat brain catecholamines. Liquid crystal compounds are
routinely purified commercially at 50 g per injection."
source: HPLC: A Practical User’s Guide, Second Edition, by Marvin C. McMaster
But I think you should state your budget.
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Metacelsus
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I second the idea of HPLC. In my analytical chemistry lab class at my university, we analyzed antihistamine pills this way.
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DutchChemistryBox
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I've worked for three pharmaceutical companies. In all companies we used HPLC and/or GC for the assays, purity analysis and for the analysis of most
impurities.
The drugs we analysed were small organic molecules.
[Edited on 6-7-2016 by DutchChemistryBox]
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unionised
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What do you mean by " VERY accurately"?
It's fairly easy to get 1% relative for most materials/
Would knowing that the pill that said it had 5 mg of material in it actually contained 4.95 +/- 0.05 mg be good enough?
Given that pills are taken by people who might easily weigh anywhere from 60Kg to 160Kg the absolute dose isn't actually needed very accurately.
For most compounds HPLC will do the job- it's fairly simple and robust.
Measuring the amount in a person's blood to that precision would be rather more difficult- partly because it has been diluted so much, and also
because there's lost of other stuff to mess up the analysis.
However, if you actually (for some reason) want very accurate measurements- say better than 0.1%- you will have difficulties- though it's still
possible for some cases.
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Fulmen
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It depends on the target chemical. If it's volatile a GC is usually the preferred choice, if not HPLC.
When it comes to extraction techniques it again depends on the target chemical. A good method is to add a known amount of a compound with similar
properties, this can then be analyzed to establish extraction yield.
We're not banging rocks together here. We know how to put a man back together.
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