Up until recently. it was believed that pharmaceutical drugs and their metabolites enter into the cell to gain access to their targets via simple diffusion across the hydrophobic lipid cellular membrane. at a rate which is based on their lipophilicity. An increasing amount of evidence indicates that the phospholipid bilayer-mediated drug diffusion is in fact negligible. https://www.bekindtopets.com/super-pick-Rx-Quadruple-Topical-Ointment-Quadritrop-for-Dogs-Cats-30-mL-super-grab/