I have a drug which is only soluble in DMSO and I need to inject postnatal mice via IP for 5 days. The stock concentration of the drug is 5 mg/mL, and the needed injection dose for the mice is 70 mg/kg.
I had calculated that a 1 gram mouse or 0.001 kg mouse would require a 70 uL injection/daily if I diluted the 5 mg drug stock to 1 mg/mL working solution however, the DMSO % is then around 25%.
Instead I thought to make a dilution of the 5 mg stock to 250 ug/mL. Therefore a 1 gram mouse would receive 280 uL/daily and the DMSO % is around 5% which seems to be what others have suggested from what I have seen.
Firstly can anyone advise if my calculations are correct? and if the volume of fluid to be injected is ok for a mouse so small.
Thanks.
i would like to know too, but here how i calculate concetration and i dont know if this is correct or not
mice with 30g weight : dose needed 70mg/kg
1kg=1000gr 70mg
30gr (1 mouce) ? (30*70)/1000= 2.1mg per mouse
and from stock solution 50mg/mL
50mg 1mL
2.1 mg ? (2.1*1)/50=0.042mL = 42 uL
so i think if you take 42uL from the stock solution is like taking the dose 2.1mg of your drug
i hope this may be helpful to you
Thank you for your reply Meriem. I believe this to be correct as using your method I got the same answer for my 1g mouse.
(1*70)/1000 =0.07
0.07/0.25=0.28 or 280 uL
David Hughes Does your Drug come in DMSO or as a powder and you dilute it in DMSO ? Because i recently used a drug that should be diluted in DMSO i made lot of mistakes i would like to give you my experience. if it says that it should be disolved in DMSO you should use only DMSO otherwise it won't dissolve in other solvant, as for DMSO it should be 5% so you can inject it in mouse or rat.
i calculated as follow :
1) 1 ug for 1 mouse and i use 10 mice so it is 10 ug per day for 7 days => 70 ug
2) inj volume i found that it should not exceed 50 ul for mouse i have used 30 ul 1 mouse so 10 mice for 7 days 2100 ul
3) 5% DMSO means that 5% of 2100 ul is DMSO so i needed 105 ul of DMSO and the rest i used distilated water means 1995 ul
5) and then when i prepared the solution i devided it at 7 days (tubes) and each day i use insuline seringue to take 30 ul of the solution to make inject
BUT: *be aware of the stock solution because never diluate DMSO then add the drug because it won't dissolve, add 70 ug (drug)+ 105 ul DMSO let dissolve then add the distilated water to diluate DMSO.
** I recommande you to let your drug in DMSO untill the day you will do the injection then add the distilated water because maybe when you put your solution and let it in the fridge it will have this preciptations and it won't dissolve again.
Good luck