Neutral drug: Why dilution is recommended for fasted state biorelevant media

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Sample dilution helps to prevent drug precipitation, minimize drug degradation, improving drug stability and change in chromatographic properties.  


Diluent for neutral drug in fasted state biorelevant media

For neutral drug molecules, methanol and water mixture (ratio 75:25) is generally recommended as the diluent to prepare the standard and dilute the sample. Acetonitrile should be avoided, as it may cause phase separation of biorelevant media.  


No dilution risks precipitation

If samples are injected without dilution, there is a significant risk of precipitation prior to drug analysis on the column.



Drug precipitation can result in retention shift, pressure build up and shortened life of HPLC column.