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giang nidqc
Junior

Vietnam,
2018-09-10 09:39

Posting: # 19254
Views: 381
 

 Simultaneous analytical method [Bioanalytics]

Dear all,
In my lab, we have validated an analytical method for simultaneous determination of 5 AIs.
Can we use this method for the determination of less than 5 AIs (ex: AI 1 and AI 3).
Is there any other requirements for doing this?
Regard,
Obinoscopy
Junior

Nigeria,
2018-09-11 21:22

@ giang nidqc
Posting: # 19261
Views: 301
 

 Simultaneous analytical method

Dear Giang,

Do you mean API? The only thing that comes to my head when you mention AI is Artificial Intelligence :-)

If you were referring to API, I wonder how you were able to perform an analytical run on all 5 analytes simultaneously. Can you explain how you did it?

Scopy
giang nidqc
Junior

Vietnam,
2018-09-12 03:37

@ Obinoscopy
Posting: # 19266
Views: 294
 

 Simultaneous analytical method

Dear Obinoscopy,

» Do you mean API?

Yes. I meant APIs

» If you were referring to API, I wonder how you were able to perform an analytical run on all 5 analytes simultaneously. Can you explain how you did it?

It's a bioanalytical method for determination of 5 anti-TB drugs by LC-MS/MS. One just raise the question: Can we apply this method for just 2/3 APIs? Is there any infuence or differences? Do we need to revalidate the method, partial or full, and which criteria? Many thanks!
Obinoscopy
Junior

Nigeria,
2018-09-12 09:35

@ giang nidqc
Posting: # 19268
Views: 275
 

 Simultaneous analytical method

Dear Giang

» It's a bioanalytical method for determination of 5 anti-TB drugs by LC-MS/MS. One just raise the question: Can we apply this method for just 2/3 APIs? Is there any infuence or differences? Do we need to revalidate the method, partial or full, and which criteria? Many thanks!

I don't think you need to revalidate as long as the 2/3 APIs were among the 5 APIs that were validated.

But if I may ask, did you include all the CCs and QCs for the entire 5 APIs in the same analytical run?

Scopy
giang nidqc
Junior

Vietnam,
2018-09-13 03:50

@ Obinoscopy
Posting: # 19284
Views: 264
 

 Simultaneous analytical method

Dear Obinoscopy

» I don't think you need to revalidate as long as the 2/3 APIs were among the 5 APIs that were validated.

Could it be a possibility that the absence of one APIs may affect the final concentration of other APIs (regarding sample preparation and peak response)?
Helmut
Hero
avatar
Homepage
Vienna, Austria,
2018-09-13 11:25

@ giang nidqc
Posting: # 19285
Views: 245
 

 Simultaneous analytical method

Hi giang nidqc,

» Could it be a possibility that the absence of one APIs may affect the final concentration of other APIs (regarding sample preparation and peak response)?

Sample preparation

Impossible. Regardless whether you use LLE or SPE each analyte follows the law of mass action (driven by pH, lipophilicity) independent from other analytes. The amount of the “target phase” (organic solvent, RP- or exchange resin) is 6 to 12 orders of magnitude higher than the one of the analyte. Hence, the presence / absence of other analyte(s) in a similar – low – amount is simply irrelevant. It can never change the equilibrium constant.

Chromatography

Unless you have an insufficient separation, no. Only if peaks overlap, in MS ion-suppression/enhancement by one analyte could influence the response of the other.

Ligand-binding assays

Can be problematic if you have a substantial degree of cross-reactivity.


Cheers,
Helmut Schütz
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Ohlbe
Hero

France,
2018-09-13 14:06

@ giang nidqc
Posting: # 19287
Views: 239
 

 Simultaneous analytical method

Dear giang nidqc

» Could it be a possibility that the absence of one APIs may affect the final concentration of other APIs (regarding sample preparation and peak response)?

I agree with Helmut's post above. There is just one thing I'm thinking of: how was the spiking of calibration and QC samples done when you used 5 analytes ? Did you use a single spiking solution containing all analytes (usual practice), or separate working solutions ? If you used a single, combined solution at each level concentration, no problem. If you used separate spiking solutions, you will have a different proportion of solvent added to the plasma if you have less analytes, which may influence your recovery and matrix effects.

Regards
Ohlbe
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