I found one source that gave the DMSO solubility as 100 mg/ml. If you are limited to using 0.2% DMSO, then you would have to dilute this stock solution 500-fold, to 0.2 mg/ml. To dose 40 mg/kg to a 20 gram mouse, you would have to give 0.8 mg, which would require 4 ml. This is too much volume to give a mouse all at once. You will probably have to find a more concentrated formulation.

Thanks so much :)

As far as my knowledge instead of going for DMSO (which is highly toxic) as vehicle for invivo studies you can go with 0.1 % to 0.5% CMC as vehiche.