Hi, I am doing the HPLC Impurity Method Transfer to the contract lab.

As per method transfer protocol I made six preparations from a single lot of API sample, but Impurity xyz % RSD (six impurity preps) failed 17% (spec 15%).

Interesting thing here is only %RSD of impurity xyz failed but imprity xyz is still within the spec 0.2% (spec. is <0.25%) as per Certificae of Analyis (COA).

Should i initiate the oos investigation ?
or Repeat the whole testing by making six preps and if % RSD passe then just mention in the method trasfer report that %RSD WAS NOT ACHIEVED SO TESTING WAS REPEATED.

i think sample %RSD Failure is not an OOS investigation.

HPLC = High Performance Liquid Chromatography

Anyone have any background that can aid the OP?

Carol,
This is a pharmaceutical good manufacturing practice (GMP) thread, so not sure if it is in the right place. OOS stands for 'out of specification' and would need an investigation into the causes and impacts and subsequent CAPA.

:topic:Carol,
This is a pharmaceutical good manufacturing practice (GMP) thread, so not sure if it is in the right place. OOS stands for 'out of specification' and would need an investigation into the causes and impacts and subsequent CAPA.

Thanks, curryassassin - I will leave it here for now, since we don't have a seperate forum for GMPs - they tend to fall in this catergory.

What is the detection limit on the method? This may be a one-sided specification where RSD is not applicable. Is there a standard method that you can reference?