Specifi optical rotation relation

[ananthjkumar]

Relationship between SOR & GC result.

Is there any correlation

[krickos]

Hi

Yes, in theory there is a relationsship between SOR and for instance a LC/GC chiral analysis.

Pratically as SOR is not that accurate and often not particular sensitive, you will not see the relationship unless on a larger scale. Observing a relationship for a substance with a SOR of for example 10-20° verus +/- 0,1% change in LC/GC results are in my experiance not possible.

Consequently at least for pharmaceutical drugs, it is preferble to use optical rotation (OR not SOR) to verify that racemates are racemates and chiral LC/GC/CE for identity of "pure" enantiomers and limit of the wrong enantiomer.

[achkata]

HI

krickos,
if chiral LC/GC is more accurate, why do you prefer to test drug racemates with OR?

greetings,
Angelo

[ananthjkumar]

but my clarification is whether we can able to get in GC analysis

[krickos]

HI

krickos,
if chiral LC/GC is more accurate, why do you prefer to test drug racemates with OR?

greetings,
Angelo

Hi Angelo.
Lets say there is a racemate drug substance avaible on the market as well as an enantiomer pure form. then it is sufficient for identity purposes to use OR to confirm identity for the racemate ie OR is +/- 0,10°.
Generally it is not value/quality/safety adding to add a chromatographic chiral analysis on top on OR for racemates, "simpler/cheaper" techniques can do a good enough work.

[krickos]

but my clarification is whether we can able to get in GC analysis

Ahh you mean like replacing SOR with chiral GC analysis?

Yes that it is possible regulatory wise, we also convinced USP/Ph Eur in a monograph to remove SOR as standard requirement as there was a chiral chromatographic requirement as well.

[achkata]

Hi, Krickos,
I agreed

thanks