Detection of methylene blue residue and its application in the preparation of anti-SARS-CoV-2 virus-inactivated plasma

Objective: To establish a detection method for the methylene blue residues in inactivated plasma against SARS-CoV-2, and to apply the method to inactivated plasma of different dosages Methods: Methylene blue in plasma was absorbed using solid phase extraction cartridge, and the absorbance at 654 nm was measured by UV-2550 spectrophotometer The absorbance of the eluate extract from standard control plasma and virus inactivated plasma by solid phase was measured, and the methylene blue residue in the test plasma was calculated based on the ratio of the absorbance Then, linearity-range, precision, accuracy and quantitative limit of the method are validated based on 11 batches of inactivated plasma in specifications of 50, 75 and 100 mL Results: The detection method of methylene blue residue, was established within the linear range of 0 01~0 05 μmol•L-1 The verification standards are as follows: R value is 0 994 4;precision is 7% and accuracy is between 102%~110%;and the quantitative limit is 0 013 μmol•L-1;the quantitative detection CV is less than 5%, all of which are in conformity with requirements of Pharmacopoeia of PRC (Edition 2015) The levels of methylene blue residue in inactivated plasma of each specification were within the detection range of the developed method, and the residue levels were much lower than that in standard(≤0 30 μmol•L-1) Conclusion: The method can be successfully applied for the detection of methylene blue residues in the inactivated plasma against SARS-COV-2 of different specifications