Submicron Emulsion Vehicle for Enhanced Transdermal Delivery of Steroidal and Nonsteroidal Antiinflammatory Drugs

Abstract

Significant improvement is demonstrated for transdermal delivery of steroidal and nonsteroidal antiinflammatory drugs (NSAID), including betamethasone valerate and dipropionate, indomethacin, diclofenac, piroxicam, and naproxen, when formulated in a submicron Emulsion (SME) vehicle rather than in standard creams. SMEs comprise oil droplets, with mean size of ∼100nm (0.1 µm), dispersed in a continuous water phase. Hydrophobic drugs are incorporated into the oil phase of the SME, resulting in improved penetration and increased efficacy of the incorporated antiinflammatory drug. The performance of medicated topical SME was compared with that of regular topical cream formulations, as measured by the carrageenan‐induced paw edema rat model. Indomethacin in SME topical vehicle was 50% more active than in regular cream base, Diclofenac in SME proved to be 40% more active than Voltaren Emulgel. Improvement of steroidal antiinflammatory drugs action in topical SME cream was even more pronounced; that is, up to 3–4‐fold. Antiinflammatory drugs in SME also demonstrate noticeable systemic activity, but for regional edema treatment, local delivery is advantageous. The new SME delivery system was tested for primary irritation in humans in a 48‐h trial. Low irritancy and excellent human acceptance for SME placebo or diclofenac‐loaded SME cream make this novel transdermal/topical DDS attractive for further development.