Dear Renata,

Do you know pKa value of dexchlorpheniramine maleate?

Regards,
Syx

whether the enalapril maleate tablets test can be done without placebo, the maleic peak how can confirm

We have more than one of API in our formula. I use pH 2.5 and 0.2% TEA on CN-column. The tailing is still between 1.5 - 2.0. We cannot add more TEA to reduce Tf because the peaks of our API will very close.
Any suggestion?

Syx,
What do you have in your formula. Can you specify?

Betamethasone valerate - dexchlorpheniramine maleate

Hi people!

I'm trying to develop a method for Dexchlorpheniramine maleate. The mobile phase chosen is Phosphate Buffer 20 mM pH 6,2 and Acetonitrile.

Well, the problem is that 2 peaks appear....
one of them is ok with SST, but the other seems to be a great and large mountain.

I thought "maybe, this horrible peak is maleate, and the perfect one, dexchorpheniramine. ". But I made a test with Enalapril maleate (just to check the maleate) using the same conditions and NO GREAT AND LARGE MOUNTAIN, and no PERFECT peak.

I ended up understanding nothing... if it's not maleate maybe is dexchlor, but the first peak isn't maleate either... so dexchlor gives me two peaks????? (many exclamation marks in my mind)

Any light to clarify my ideas??

Thanks (again)

Renata

Enalapril can give you broad peaks due to interconversion of conformers during the HPLC run.
There is no reason for this to happen with your chlorpheniramine metabolite. Try to get some pure maleic acid or maleate to see if the other peak is maleic acid.

thanks Uwe.

I'll try to get it...

Renata

Try pH 3.0, add mobile phase modifier, like triethylamine, you will get maleate peak, early in chromatogram.. active peak should be better now.

ok I'll try this one

Thanks a lot.

Renata