Considering KF controlling is important for next step (step 5), if KF higher than 0.2%, the reaction cannot completion during step5. And BI can reach to 0.4% after drying, also Asymchem lab use test and Demo batch can also reach to NMT 0.5 %( 0.3-0.5%). So Asymchem controlled water tightly to 0.5% during establish specifications for step3 intermediate.
BI sited the LOD and KF both NMT 3% in there TP, in our understanding, LOD should be the summation of KF and solvent. During previous meeting with BI, we need to site solvent and KF instead of LOD. Due to 3 solvents may bring into this intermediate, so we tightened the KF.
But after later study on step 5, it shows water can be removed by concertation along with toluene, so we added an IPC after concentration. If KF not qualified, we can charge some toluene and concentration again. And use test shows the mixture is stable during concentration.
Besides, we did a use test for batch CPo124194-01-03-01 and a contrast experiment to increase water to 5% retaliated to Asym-124355 and a contrast experiment to increase water and ethanol both to 5% retaliated to Asym-124355. Details refer to