Hi,

As you are using saline for control group, to avoid any experimental bias, you should use same saline solution as solvent for drug loaded chitosan nanoparticles as well. However, the best control will be to use blank chitosan nanoparticles in saline (if you chose it as solvent) for control group and drug loaded chitosan nanoparticles in saline for treatment group. In this way, the effect (if any) that you will observe in the treatment group can be attributable to the drug only and will remove any bias due to chitosan nanoparticle or saline as rest everything is same between the two groups, only drug is the additional thing in treatment group.

Hope this might have helped.

Cheers,

Apurva