Interference

[morningstar]

Hi all,

I have a problem with the product i'm handling right now,

Basically the drug i'm dealing with is UV non-active compound, so obviously its has to be derivatised and estimated (i mean one of the methods)

Recently when i've performed the dissolution in purified water, the disso result was on higher side

i thought this might be due to some interference, so i injected the placebo. there was a small peak at thr RT of the analyte, but i don't think it would contribute to such high results. even then i took the placebo interference in to consideration and injected all the indiviual excipients to see which one of them was contributing, but i found nothing

is there any chance of increase in the derivatisation speed or extent due to placebo?

because, i found this strange thing ....when i spiked the API with placebo and derivatised it it gave me one area, but when i added placebo to already treated or derivatised API and injected i got a peak area which was less than the "one spiked and then treated"


what could be the reason?


need your help regarding this



regards

morningstar

[Mark Tracy]

It sounds like there is something in the placebo that reacts with your derivitizing agent, and furthermore coelutes with the API. Since the excipients one by one don't show any signal, perhaps the placebo is contaminated. Try a different batch of placebo. You may find yourself over at the LC/MS to untangle this problem.

[morningstar]

Hi,

I've tried it with a fresh batch of placebo but no use

I've spike the api with individual excipients and ijected on to HPLC strangely the one spiked with MCC shows a higher area than that of the API alone, but in what way is the reagent reacts with MCC(incase it does)