Chiral Methods for Assay and Impurities

[adam]

We have a chiral pharmaceutical and so we will, of course, have to develop a chiral method to separate the enantiomers.

My questions is this: does anyone know if it's possible to do this and, simultaneously, separate the impurities. In other words, is there a chiral column that can also provide some "reversed phase" type mechanism to separate the non-chiral molecules. The idea is to do both the enantiomer analysis and the related substances with one method. Is it possible?

Thanks very much.

[Bruce Hamilton]

It probably depends on how lucky you are. The chiral column that separates your enantiomers may also separate all of the related substances.

More likely, it will, at best, separate only some, depending on the number present and their structure. If you only have a couple, you might be lucky.

Your first step would be to discuss the issue, and provide structures, with chiral column suppliers such as Astec, Regis, Daicel, etc.

Good luck, and please keep having fun,

Bruce Hamilton

[adam]

Of the various chiral phases available, is any one preferred for what we are trying to accomplish?

[Bruce Hamilton]

Of the various chiral phases available, is any one preferred for what we are trying to accomplish?

You really need to show the structures of the compound and likely impurities to chiral column manufacturers, and find out which columns will separate your enantiomers first, and they may then suggest which can also separate the impurities.

Another possibility is to derivatise your compound so the derivatives will resolve on conventional columns, and those columns may also resolve your impurities.

As noted above, the best people to talk to are technical support people from chiral column manufacturers, such as Astec, Regis, Daicel etc..

Bruce Hamilton

[Kelly Johnson]

ZirChrom also offers a line of Pirkel type Chiral phases. I would be happy to help you directly if you would like - e-mail is support@zirchrom.com.

Good Luck!

Kelly

[mardexis]

Hi Adam,

I agree that depends entirely on how lucky you are. As a course of action it would be wise to focus on the chiral separation... they are usually the most difficult. If you find something that gives good resolution of just your enantiomers then you are already a little lucky. Worry about the rest of it later.

When doing the chiral analysis you should feel free to add gradients to your separation. This might give you more of your impurities than simple isocratic. Just so long as you are within the range of solvents allowed for the column.