Chromatography Forum

Hello, I am currently working on a acne gel which contains Benzoyl Peroxide and Clindamycin Phosphate as active ingredients. I am looking for one procedure to identify the compositions of both of these compounds together. Thank you in advance.

Oooh, good luck with that one. Separating them using HPLC will likely not be a problem. It's the detecting that will be your issue. The peroxide has a benzene ring so you'll have a prayer with HPLC and a uv-light detector. That clindamycin doesn't have a good chromophore so a light detector might not work very well. You might have LCMS as your only option to get both in one shot.

Do you have the option to consider another technique? I just saw an article in one of my google alerts for getting benzoyl peroxide by NIR. Perhaps a technique like that would be a good approach for your problem?

Hello rb6banjo and thank you for your reply, the thing is we do not have fancy equipment. We only have a standard spectrophotometer and HPLC. Ive looked all over the internet for methods with titration and I could not find any of that sort. If you have a method for only Benzoyl Peroxide by itself, do not hesitate to include it here.

Have you checked "Google Scholar" for leads on how you might do this? It's a great - free-of-charge - way to find a lot of scientific information. At least it will point you to abstracts of papers that can get you on the right track.

I found a review in Analytical Chemistry:

Anal. Chem. 2007, 79, 4275-4294

that has the title "Pharmaceuticals and Related Drugs". In that paper, this paper is referenced as a chemiluminescence method for clindamycin.

(G44) Shao, X.; Xie, X.; Liu, Y.; Song, Z. J. Pharm. Biomed. Anal., 2006, 41 (2), 667-670.

I'm fairly confident you can find good mobile phase conditions to determine the benzoyl peroxide. The benzene ring is a fairly good chromophore in the uv.