Isomer Sepration in Liquid Chromatography

[HITESHPATEL]

I am devloping a Method of Related compound in Softgeletin capsules which is made from Medium chain triglyceride oil,

My problem is, I devloped related compound method in normal phse chromatography and there are three isomers (Impurities ) which are eluting on same RT, I change in mobile phase and I also used chiral column which is IA 4.6mm x 250mm, 5µ but still not able to seprat two isomers which are eluting on same RT.

If you have any idea about the sepration isomer (any chiral column) or (mobiloe phase) please let me know.

Thanks
Hitesh P



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[Gerhard Kratz]

Hello Hitesh, please try also silica gel with phase-bonded cyanoethyl and mobile phase hexane-isopropanol-formic acid by HPLC with RI detection. And I found on the Supelco website an application note on TG's: Triglyceride Isomers
Single-step separation may not be possible for certain compositionally
distinct triglycerides or certain positional isomers. Compositionally
distinct triglycerides such as O3 (54:3) and OLS (54:3)
have the same total acyl carbon number and degree of
unsaturation. Isomers such as OOP, OPO, and POO differ only in
positional or chiral considerations. A means, such as that described
by Brockerhoff (2), is necessary for identification of these
coeluting compounds. Recent work indicates that the SUPELCOSIL
LC-18 column, used with a nonaqueous mobile phase, can
separate cis-trans isomers such as triolein and trielaidin (Figure C).
The one-step separation by both carbon number and degree of
unsaturation is a significant improvement in analytical capabilities
and should prove to be a valuable tool for triglyceride analyses.

And if you use this link: http://www.usp.org/USPNF/columnsDB.html you can find all other columns similar to the above mentioned column.
I hope that will help. BR Gerhard

[krickos]

Hi Hitesh P

This forum can be very helpful, provided one submits enough with information, unfourtunately I find your question lacking in more detailed information just like the other ongoing soft gelatin thread, also it is confusing.

Apart from more analytical details one wounder:

What are you really trying to do? You mention a related substances method for a drug product, but you only mention the excipient (Medium chain triglyceride oil) without info on the drug substance we are fumbling in the dark.

So is the isomers/impurities which you seem to know, orginating from the drug substance or the oil?
When I used to work on something similar (drug dissolved in oil) we extracted the drug substance and all its impurites before LC analysis.

If you work with medium chained triglycrides that should comply with the Ph Eur monograph, then the saturated fatty acids should mainly be C8 and C10 (something like fractionated coconut oil).

[HITESHPATEL]

Hi Hitesh P

This forum can be very helpful, provided one submits enough with information, unfourtunately I find your question lacking in more detailed information just like the other ongoing soft gelatin thread, also it is confusing. Sorry About the lacking of information [/b][/color]

Apart from more analytical details one wounder:

What are you really trying to do? You mention a related substances method for a drug product, but you only mention the excipient (Medium chain triglyceride oil) without info on the drug substance we are fumbling in the dark.
[b]I am working on Vitamin D Drug substance which is dissolved in MCT oil (Soft gel Capsules ) and I am trying to seprate three Isomers which are eluting on same RT (Process Impurities) of Vitamin D. [/b]

So is the isomers/impurities which you seem to know, orginating from the drug substance or the oil? Orginating From The Drug Substance of Vitamin DWhen I used to work on something similar (drug dissolved in oil) we extracted the drug substance and all its impurites before LC analysis.

If you work with medium chained triglycrides that should comply with the Ph Eur monograph, then the saturated fatty acids should mainly be C8 and C10 (something like fractionated coconut oil).