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mass balance in stability study

Posted: Thu Jun 18, 2020 6:10 am
by shahnaz khan1
Hi,
I am doing a stability study of vitamin D3 injection. The Assay method for D3 quantitation is BP based UV method whereas impurities are identified using a validated HPLC method.
The stability profile of the product at different time points looks like this

Assay: 106.2%, 106.5%, 101.5%, 98.2%, 97.2%
% impurities: 0.12% , 0.14% , 0.19% , 0.25%, 1.17%

My query is that active is broken down about 9.0% from initial time point to last time point but I don't see 9.0% increase in impurities (but only 1.17%). Are these results acceptable even if we cannot find the mass balance? Is this significant increase in %impurity enough for presenting stability results?
Note: None of the impurities have RRF of more than 1.5.
Thanks,
Shahnaz.

Re: mass balance in stability study

Posted: Fri Jun 26, 2020 12:28 am
by bash94
Hello,

May I ask what was the initial purity of the Raw Material that has been used to prepare stability batch ?

Re: mass balance in stability study

Posted: Tue Jun 30, 2020 12:44 am
by shahnaz khan1
bash94 wrote:
Hello,

May I ask what was the initial purity of the Raw Material that has been used to prepare stability batch ?


Hi,
The initial purity of Raw material was 101.0%. Stability batches have 5% overage.
regards

Re: mass balance in stability study

Posted: Wed Jul 01, 2020 5:20 am
by Ice9
Detection type, is the missing imppurities invisible to UV(or the wavelength) do toy have PDA/DAD to take 3d info. Can you run it on LC-MS?