Rosuvastatin photolytic degradation

[CHRISCHAR]

Hallo to everyone,
We have notice that during forced degradation experiment on Rosuvastatin Ca tablets, two major degradation products were produced. They are not lactone or 5-ketoacid and apparently are less polar than them as their RT is bigger. Has anyone study these two products, or just have an idea about their formula?
Thanks in advance

[HPLC chemist]

They could be particular to your own process, dosage form, or packaging! The related substance in the finished dosage form (in addition to the raw material) can come from;

1. Reaction product between the API and the your unique formulation
2. Reaction product between the API and the component packaging system

The only way you can confirm the structure of the related substance is by MS. Then you will have to postulate a degradation pathway and specification (after mass balance).

[CHRISCHAR]

Thanks for your answer,
the problem is that we do not have an HPLC-MS in our lab. Also, these impurities are not come form the interaction with the excipients as apparently arrears also during forced degradation of the raw material (our provider also shown them in his forced degradation (in DMF file). But he did not say anything more on that).
Anyway, that's why I post it, in case that someone has done any investigation on that subject.
have a nice day

[HPLC chemist]

Understood. We had to contract out the MS investigation to Magellan Labs because we did not have an MS either. However, we sent them samples with RS identified by RRT that were accelerated. Forced degradation is very extreme and peaks found are not necessarily found in commercial stability samples (accelerated or long term).

For FD investigation I would only identify the source (ative API or placebo excipients) based on the relative retention time (RRT).