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# Drug concentration

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### #1 Peniel

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Posted 04 March 2013 - 07:18 AM

This question might seems stupid but please bear with me I'm quite new at this. I want to use a cytotoxic drug on some cancer cell line. The drug is available in 10mg and 50mg. I need to dose this cell lines with 75mg, 150mg, 300mg, 600mg, 1000mg and 1200mg each day. the molecular mass of the drug is 236.29. How do I work it out. Will I have to buy many of this compound?

Thanks for your help

### #2 jerryshelly1

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Posted 04 March 2013 - 07:28 AM

There is no shame in this. Everyone needs a refresher once in a while. Review the below material. It is difficult to answer your question because you are not indicating the final volume you would be working with. Good luck.

http://dl.clackamas....04/calculat.htm

### #3 Peniel

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Posted 04 March 2013 - 08:37 AM

Hi jerryshelly1, thanks for those links. I need to dispense 100ul in each well but I'll make up a stock solution of 10ml. I hope I make sense.

### #4 almost a doctor

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Posted 04 March 2013 - 09:41 AM

The drug is available in 10mg and 50mg. I need to dose this cell lines with 75mg, 150mg, 300mg, 600mg, 1000mg and 1200mg each day. the molecular mass of the drug is 236.29.

Are you sure those amounts are right? I mean... 1200mg = 1.2grams sounds like a lot for invitro assays!! Furthermore, if you are talking in mg the molecular mass of the drug is irrelevant, as is the volume you might use.

If your amounts are the correct ones, and the drug comes in 10mg and 50mg, yes you are going to have to buy loads.... 75+150+300+600+1000+1200=3325mg... and that will be just for one day for one well! (if I've understood your post correctly that is).

### #5 Peniel

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Posted 04 March 2013 - 01:45 PM

Wow that will be too expensive. The drug is quite weak and it is admistered at 600mg given 4 times daily. The supplier says the IC50 is 2.6uM. Do I just use the supplier's infomation and work from 2.6uM to about 10mM? What do you suggest?

### #6 jerryshelly1

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Posted 04 March 2013 - 02:21 PM

Peniel. I think you are confusing your nomenclature. Are you referring to 75, 150, etc... mg/L, mg/mL, etc.? No drug manufacturer is going to provide recommended concentrations of just mg.

### #7 Peniel

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Posted 05 March 2013 - 09:25 AM

The manufacture indicates that the IC50 of the drug is 2.6microMolar. The drug comes in either a 10mg or 50mg pot. It does not say if it is ml or L but I'm assuming it is mg/ml. This is my first time working with drugs so I'm not very sure about the details.

### #8 mdfenko

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Posted 05 March 2013 - 11:52 AM

The manufacture indicates that the IC50 of the drug is 2.6microMolar. The drug comes in either a 10mg or 50mg pot. It does not say if it is ml or L but I'm assuming it is mg/ml. This is my first time working with drugs so I'm not very sure about the details.

the drug is probably just 10 or 50mg dry. you have to solubilize to a convenient concentration.

2.6uM is 614.354 ug/L. i think that your desire to use 75-1200mg/day is mistaken in units.

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### #9 Peniel

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Posted 06 March 2013 - 12:15 AM

The manufacture indicates that the IC50 of the drug is 2.6microMolar. The drug comes in either a 10mg or 50mg pot. It does not say if it is ml or L but I'm assuming it is mg/ml. This is my first time working with drugs so I'm not very sure about the details.

the drug is probably just 10 or 50mg dry. you have to solubilize to a convenient concentration.

2.6uM is 614.354 ug/L. i think that your desire to use 75-1200mg/day is mistaken in units.

Yeah it is dry 10 or 50mg and I desire to use 72 - 1200mg/day. You got it. I'm going to solubilize in 0.01% DMSO. How can I achieve dosing them at 75mg per day? The cells and drug need to be 100ul per well. I am sorry for being a nuisance. I appreciate the help.

### #10 mdfenko

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Posted 06 March 2013 - 05:11 AM

to dose at 75mg you will have to resuspend two 50mg vials. that will give you 100mg in the volume of solvent you used to suspend the compound.

take 3/4 of the volume and adjust to 100ul.

every 4th day you will be able to use the remainders from the other 3 days for that day's dose.

for 150mg you will need 3 vials of 50mg/day; 300mg will require 6 vials/day;...

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### #11 Peniel

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Posted 06 March 2013 - 06:23 AM

to dose at 75mg you will have to resuspend two 50mg vials. that will give you 100mg in the volume of solvent you used to suspend the compound.

take 3/4 of the volume and adjust to 100ul.

every 4th day you will be able to use the remainders from the other 3 days for that day's dose.

for 150mg you will need 3 vials of 50mg/day; 300mg will require 6 vials/day;...

Thanks mdfenko. That will be too expensive and my supervisor will not be willing to purchase that quantity. I'll work with lower molar concentration and see what happens. Thanks for your help.

### #12 Peniel

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Posted 07 March 2013 - 02:22 AM

to dose at 75mg you will have to resuspend two 50mg vials. that will give you 100mg in the volume of solvent you used to suspend the compound.

take 3/4 of the volume and adjust to 100ul.

every 4th day you will be able to use the remainders from the other 3 days for that day's dose.

for 150mg you will need 3 vials of 50mg/day; 300mg will require 6 vials/day;...

Is there a way or formula to calculate drug concentration in the plasma from the dose adminstered or what is the best way to get this information.

For example The concentration of Celecoxib calulated based on the steady state plasma concentration of 1ug/ml at the dose of 400mg per day was 2.6uM.

I checked the reference but could not work out how the research came about this information.

Thanks.

### #13 mdfenko

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Posted 07 March 2013 - 05:59 AM

i would imagine that they actually checked the level of the drug in the subjects' plasma.

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