We are trying to set up an experiment in our lab to study IMQ induced Psoriasis. We have a query regarding the solvent that can be used to check IMQ solubility.
The reference suggests using micellar solution method to improve the solubility. Table 2 in the document summarizes solubility data for this method with compositions, and pH. In other literature the solubility is just so low, but to get something significant enough you will have to go micellular method.