Hey,

Disclaimer: This is my first post so I hope this is in the right section. 

I'm doing an experiment on different anticoagulants by comparing how they effect different specific clotting factors (measured via a factor activity assay). 

I have 2.5 mg of apixaban (in tablet form) and I wanted to make a stock solution out of it and then use 5 different final concentrations ranging from say 0 - 800 ng/ml i.e. 50ng/ml ... 150 ng/ml etc and use these solutions to spike normal plasma samples. Then I will perform the activity assays.

I have only have a limited supply of the anticoagulants in tablet forms and was wondering how I could make the final concentrations i.e. the stock then the exact concentrations I need. I'm dissolving the drugs in distilled water and not DMSO

Any help is appreciated

Edited January 13, 20187 yr by Shinra123

I would suggest making a stock to 0.5 mg / mL, then dilute from there. It depends on how good your scales are though. Once you have your stock, make up your highest concentration (1 uL stock made up to 625 uL) to at least double the required volume and the rest by performing a number of serial 1:2 dilutions until you get the range you need. 

 

2 hours ago, hypervalent_iodine said:

I would suggest making a stock to 0.5 mg / mL, then dilute from there. It depends on how good your scales are though. Once you have your stock, make up your highest concentration (1 uL stock made up to 625 uL) to at least double the required volume and the rest by performing a number of serial 1:2 dilutions until you get the range you need. 

Thanks for the reply.

I just have a couple of follow up questions. What do you mean by the double required volume (I ul ?) and could you elaborate on how to do the 1:2 dilutions to get the desired range which is 0-800ng/ml so 0, 100, 200 etc?

 

As in, I'd make at least double what you think you need. As for the 1:2 dilutions, this is a very standard technique (serial dilution). You simply take some volume of a stock, your 800 ng / mL for example, and mix it with an equal volume of your solvent. This is now half the concentration of your first stock. Mix, then repeat with your new solution until you get the range you're after. I'm sure I don't need to tell you how to make a 0 ng / mL solution.