Refarence/working standard qualication

[sri4516]

can anyone have a relevt info on below topic and would greatly appreciate your help

Rational for the qualification of referanced standard qualification by the following tests

1. By Mass balance method
2. Assay by HPLC on dried basis.

Which is the more appropriate test parameters to quantify the reference standard
Is it depends on product specific.
Is there any relevent guidelines or info pertaining the above topic.

urs,
Sri

[e_senmail]

Dear Sri,
If reference standard available, working standard purity determined as %w/w on as is basis only whereas reference standard not available, working standard purity determined as mass balance.

Regards
e_senmail

[sri4516]

Dear e-sanmail,

Thanks for your lucid explination for the subjected topic

besides could you clarify " when we can perform characterisation for working standard" i.e., each time we have to do or any criteria is there

[ramyaraj725]

Whenever you prepare a new working standard (usually, once in a year), it should be characterized.

[e_senmail]

Dear Sri,
I agree ramyaraj statement. But working standard "characterisation" and "qualification "are different.
Qualification is your working standard qualify with pharmacopeial reference standard whereas characterisation is working standard (without pharmacopeial reference standard) characterised by using UV, IR & HPLCMS, NMR instruments to find the mass balance. Normally working standards are qualified once in a year.
I hope you clarify.
Regards
e_senmail.