Forced degradation

[himadam@hotmail.com]

I stressed sugary sample at (50C, 75% RH), the assay value using assay method 60% and impurities using related compounds method accounted for 19% impurities (RRF used), the mass balance is 60+19 =79%. Ran KF and found 10% moisture in the stressed sample. How to calculate mass balance based on 10% moisture? Is the moisture apply to assay or both (assay & impurity)? Any additional advice will be appreciated

Thanks

[Consumer Products Guy]

Don't you just need to show that your compound of interest is the same, and that any degradation products don't interfere with its chromatography?

[himadam@hotmail.com]

I want to see if I can simulate stability in commercial product, when I ran the stability sample got 30% degradation and mass balance 100.3% but my mass balance in stressed sample did not add up.

[gtma]

There is an excellent book by Steven Baertschi on forced degradation, I strongly recommend obtaining a copy. I think it will answer your Qs.

[himadam@hotmail.com]

I checked this book at Amazon and saw table of contents, it looks like a great book, I will order it.Thanks for recommendation.

[aceto_81]

I stressed sugary sample at (50C, 75% RH), the assay value using assay method 60% and impurities using related compounds method accounted for 19% impurities (RRF used), the mass balance is 60+19 =79%. Ran KF and found 10% moisture in the stressed sample. How to calculate mass balance based on 10% moisture? Is the moisture apply to assay or both (assay & impurity)? Any additional advice will be appreciated

Thanks

To answer your original post: you found 10% moisture in your sample, so assuming that you need 100mg sample, you weighted 90mg sample and 10 mg water.

So your need to do a correction for all your values, so 79% * 100/(100-10%) = 87.8% instead of 79%

Ace