Hemolysis and Matrix Effect Issues during Method Development of Promethazine in Human Plasma

摘要

Promethazine was not stable in methanol. This instability brought an issue with the linearity, specifically at the low end of the calibration curve. Acetonitrile was found the most suitable to avoid this instability. Hemolysis effect during extraction was observed. Although this did not impact the quantitation since the internal standard was equally affected, its effect on the peak area might bring rejected study samples due to abnormal internal standard response. New cation exchange SPE minimized the problem. During routine study sample analysis, it was important to evaluate the hemolysis % against a "visual chart" and additional care must be taken to inject the analytical run as soon as possible. The method was found reproducible with study samples reassays (ISR).]