Formaldehyde is the primary fixing agent in Durasole and it causes proteins to crosslink in a meshwork, stabilizing the protein mass and preserving morphology. Although it is a strong reducing agent, formaldehyde fixes by an oxidative reaction, forming methylene bridges between the side amino groups of lysine and glutamine on different protein chains. In the diagram below the methylene bridge is red.

Equid exfoliating sole and insensitive frog has no enervation or vascularity and is comprised mainly of collagen, which is a major component of the extracellular matrix that supports most tissues and gives cells structure from the outside. The primary function of the exfoliating sole and insensitive frog is to protect their sensitive analogs from concentrated environmental pressure and the aldehyde and tannic acid in Durasole create crosslinks with collagen and other forms of protein in the exfoliating sole and insensitive frog on the solar surface of the equid hoof by forming covalent bonds between adjacent amine containing groups. Crosslinking, the formation of larger molecules from the smaller molecules of the exfoliating sole and insensitive frog, greatly enhances the protective properties of the respective structures by increasing both their mechanical stability and structural integrity.

Durasole is formulated to be an extremely effective sole toughener; additionally, the latest formulation of Durasole contains gentian violet to combat fungus and yeast infections and povidone-iodine solution in sufficient concentration to be effective in the treatment of thrush when aerobic conditions are maintained at the infection site.