Dear Sir. Concerning your issue about the compatibility between polysorbate 80 and sodium sulfate. Polysorbate 80, commercially known as Tween® 80, is a nonionic surfactant and

emulsifier used in food and pharmaceuticals. Formation of peroxide in neat polysorbate 80

in the presence of air during incubation at elevated temperatures has been reported. This

can affect the stability of oxidation-sensitive drugs. Ibuprofen showed an incompatibility with polysorbate 80 in tablets stored for three weeks at 70°C/75% RH. I think the following below link may help you in your analysis:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3757851/

Thanks

Thanks

Dear Anindita, Can you share the details of the analytical method used to quantify the polysorbate 80?

Regards LG

Column – waters symmetry C18 (150x4.6)mm, 5μ

 Flow rate – 1ml/min

 Detection – By UV at 220nm

 Column oven Temperature – 25°C

 Sample cooler Temperature – 25°C

 Gradient programme

Dear Anindita, HPLC, hummm.... Yes they might affect the detection/quantification, but given the type of column and detector I can't figure out why (might be an analytical issue or due to chemical degradation as suggested by Isam).

I would try to quantify a solution containing just polysorbate and another containing polysorbate plus sodium sulfate and/or sodium bisulfite (immediately after preparation and after stress testing - temperature for instance). The results would most probably allow to conclude on the root cause for any observed change (analytical or polysorbate degradation). Hope it helps. Regards, LG

Sir,\

Thanks.

We already performed similar analysis with and without sodium bisulfite and with sodium bisulfite we haven't got any peak, though we need to estimate in complex formulation where both sodium bisulfite and PS 80 are present.

I acknowledge the information that the actual matrix is more complex than just PS80 and the 2 salts. However if you are not able to solve the "mystery" in the simplest scenario I doubt that you will succeed in the "more complex formulation".

May I ask why you need to quantify PS80? Is it a regulatory requirement (finished pharmaceutical product specifications - not common!) or part of the product pharmaceutical development phase? If it is the former one you need to find the root cause of the "peak disappearance" (analytical or chemical) and develop/modify your analytical method/setup accordingly. If it's the later case, aren't you able to indirectly asses the amount of PS80? Does your lab owns an HPLC diode array detector or a stand-alone DAD spectrophotometer? Regards, LG

Yes, the actual matrix is more complex than just PS80 and NaHSO3. It is a regulatory requirement. We are not having HPLC with DAD Detector.

Are you allowed to clarify/explain why you need to quantify PS80 as it is not a common requirement (batch release or stability)?

we need to find exact quantification.