New and established topical corticosteroids in dermatology: clinical pharmacology and therapeutic use

Currently, topical glucocorticosteroids are the most frequently used drugs in dermatologic practice. Over the years, research has focused on strategies to optimize potency and, in particular, the anti-inflammatory and immunosuppressive capacity of these drugs, while minimizing adverse effects. However, 'ideal' topical corticosteroids have not yet been synthesized. They should be able to permeate the stratum corneum and reach adequate concentrations in the skin without reaching high serum concentrations. Such characteristics can be obtained by increasing the natural lipophilicity of corticosteroids, e.g. by esterification. In the past, many structural modifications have been made to improve the efficacy of topical corticosteroids to produce drugs with greater potency, although this has often been associated with a higher likelihood of adverse effects. Betamethasone dipropionate and clobetasol propionate, known as fifth-generation corticosteroids, are a typical example of potent molecules that can control specific dermatoses very rapidly, but which are associated with a high risk of topical and systemic adverse effects. Recently, steroid components have been synthesized that aim to have adequate anti-inflammatory effects and minimal adverse effects. The newest topical corticosteroids used for the treatment of different dermatoses and allergic reactions of the respiratory tract (in particular asthma) are budesonide, mometasone furoate, prednicarbate, the di-esters 17,21-hydrocortisone aceponate and hydrocortisone-17-butyrate-21-propionate, methylprednisolone aceponate, alclometasone dipropionate, and carbothioates such as fluticasone propionate. These new topical corticosteroids are evaluated in the current review, which compares the risk/benefit ratio of each molecule with established agents. The new molecules, compared with the well known and established corticosteroids, generally have a higher anti-inflammatory effect, good compliance among patients (only a once-daily application is needed), rarely induce cross-sensitivity reactions and have weak atrophogenicity.