Chromatography Forum

Hey all

I was wondering if anyone can recommend a good method for analysis of Minocycline - separating it from its degs and from the epimer.

I did some quick searching and most of the methods I see use very atypical conditions, e.g. isopropanol in the mobile phase, unusual buffer systems, etc. I am not entirely sure what is the reason for this.

I think even things like HILIC or even classical normal phase may be a good alternative, since hydrolysis and epimerization occur much less readily in those types of mobile phases.

Well any push in the right direction would be appreciated.

Thanks
Mark

might be a good candidate for our SHARC hydrogen-bonding columns:
http://www.sielc.com/Products_Sharc.html
http://www.sielc.com/Applications_By_Publish_Date.html

or mixed-mode.

If you send me samples I can look at this in the lab.

Given all the functional groups present on this molecule I'm surprised relatively simple mobile phases can be used. I found a reference using the below conditions:

Mobile phase: 35 mM KH2PO4, pH7.5:TEA:ACN (74.5:0.5:25)
Column: Phenomenex Luna Phenyl-Hexyl analytical column (150x4.6 mm) with guard column
Detection Mode: UV detection at 280 nm
Flow rate: 1.0 mL/minute
Column temperature: 50 °C

c-18 with a ion pairing agent should work

Thanks for the replies.

But what we were hoping for was a method already available that can separate Minocycline from its epimer. This is the hard part. It's not too difficult to get a method that can quantitate Minocycline, but getting one that can separate it from its epimer - that's the trick.

Sending me a sample is always an option

Hi Vlad,

Would you classify the SHARC column as a type of normal phase column?

it operates in normal phase conditions, but some additives are required to enhance or suppress hydrogen-bonding interaction.

Here's a related reference:

http://www.basinc.com/library/presentat ... ffen02.pdf

The chromatographic conditions detailed along with example chromatograms gave separation of minocylcine from its epimer.