Drug dilution in DMSO - (Mar/09/2015 )

Hi,

I am trying to dilute my drug to 4 different concentrations and keep DMSO constant throughout. Please please help me. The final volume/well is 2000ul. My stock is 10mM. My first concentration of interest is 25uM, and I would like to dilute these by 1/5. How can I do this while keeping DMSO the same throughout? (0.2%)

THANKS!

Prepare a separate stock solution in DMSO for each dilution level. For example, use 10 mM stock for a 25 uM final concentration and 2 mM stock for a 5 uM final concentration.

Or! If you make sure that your stock solution and your diluent are the same liquids (in this case, both contain 0.2% DMSO), you'll only dilute the drug and not the DMSO when making a dilution.

For example; if your stock is 10 mM and your end concentration needs to be 25 uM = 10.000 uM / 25 uM = 25x dilution. So dilute your drug stock in 0.2% DMSO 25x in the same solvent and your DMSO concentration won't change, only your drug concentration will. Preferrably, use the same stock solution for each dilution you want to make, to avoid variation between the stocks.

Unless I'm misinterpreting your question.