There is provided pharmaceutical compositions suitable for topical application to the nail for the treatment of nail diseases such as onychomycosis, comprising a urea-based component, a diol component, such as propylene glycol, an organic acid component, such as lactic acid, and a triol component, such a glycerol. There is further provided methods of improving the storage stability of a pharmaceutical composition suitable for topical application to the skin and/or nails comprising such urea-based components, diol components, organic acid components, and, optionally, an aqueous base, which method comprises adding a triol component, such a glycerol, to that composition prior to said storage.
