How can we perform permeability studies of poorly water soluble drugs using intestinal single pass in situ perfusion assay, considering the major obstacle of their solubilization issues in perfusion buffer?

While performing in-situ single pass intestinal perfusion assays for determination of drug permeability, is it suitable to use DMSO or other co-solvents for solubilizing poorly soluble drug in perfusion buffer? 

Most of the time drug is poorly soluble in water and buffer, so in that situation what should be done. Are in situ single pass intestinal perfusion studies are not applicable for determining permeability of poorly soluble drug? In several papers, use of DMSO or methanol to overcome solubility barrier was reported. Is this a right practice? because DMSO or other cosolvents may often effects the membrane integrity...

Or there are some other appropriate alternatives. Apart from intestinal perfusion other cellular and non cellular methods are also available which can be utilized for permeability determination. But among all which method is best suited for poorly water soluble drugs and how. please provide suitable suggestions.