Often we formulate liquids into a gel or ointment formulation for preclinical wound studies.  The alternative is to put the liquid into a porous foam dressing and then apply the dressing with a bordered covering to keep it in place. Depending on the animal model, liquid treatments can be quite challenging and I would switch to a gel formulation to ensure that it is properly applied to the back of the animal.

I agree with Dr. Mitchell,

Formulate it in cream or gel or ointment. I think dont wrap or close wound after application and also no need to remove the eschar. Apply the drug at sides of the borders of eschar and also on the Top. If you dont want to make formulation then you can add your solution drop by drop if want specific quantity. If quantity does not matter then add with completly soake sterile cotton.