Problem with LC analysis of Vilazodone

[santoshgandhi]

Presently we are working on a drug vilazodone (Antidepressant) and we are having a difficulty with LC analytical method. The peak shape obtained for drug is very broad (peak width around 2 minute) as well as tailing & fronting effect. We had numerous trials using different mobile phases like methanol: phosphate buffer pH 3 adjusted by orthophosphoric acid (80:20), Acetonitrile : methanol (90:10). Also we worked at different pH (Acidic as well as Alkaline), yet could not get sharp peak. Kindly suggest solution.

[alemaggot]

what is your analyte concentration?
How many ul you inject?
What column you use?

[Gerhard Kratz]

Fronting is a problem in general issued by extra column effects, bad connections, dead volume etc.!
What is the pK of your drug?
Can you use also some volatile buffers, instead of phosphate buffer?
What column material you use, particle size etc.?
Dimension of your column can also play a role. Maybe another separation mode can do the job, like HILIC!

[emeulman]

Look at this article:

http://www.ijbpr.com/admin/fckeditor/_s ... 89-795.pdf