Topical Nanoformulations of Apremilast for Psoriasis Therapy

Psoriasis is considered a chronic, inflammatory autoimmune disorder of the skin affecting 2-5% of the world's population and is characterized by inflamed reddish erythematous plaques. There are several therapeutic drugs available for the treatment of psoriasis. Despite this, none of them is entirely safe and effective in treating the condition without jeopardizing patient compliance. Traditional topical therapies have significant drawbacks, including inadequate drug penetration, higher dose frequency, severe toxicity, and poor patient compliance. Phototherapy and systemic drugs employed in psoriasis therapy have many side effects such as hepatotoxicity, nephrotoxicity, skin cancer and high blood pressure. These complications limit the usage of currently available psoriasis treatments. Thus there is a need to look out for alternative moiety or advanced delivery systems which overcome the limitations of the current therapeutic regimens for psoriasis. Apremilast (APM) is a type 4 phosphodiesterase inhibitor authorized to treat psoriasis and psoriatic arthritis worldwide. It has low solubility and permeability and is hence categorized as a BCS class IV drug. The topical application of apremilast directly to the affected skin will avoid the problems associated with oral administration, and also, dose reduction is possible since the first-pass metabolism can be bypassed. However, due to apremilast's poor aqueous solubility, permeability and modest lipophilicity, it is not easy to deliver it to across the scaly psoriasis lesions through conventional topical formulations. The use of topical nanoformulations, especially lipid nanocarriers, can overcome the limitations mentioned above and permeate psoriatic horny layers and retain the drug in the skin layers.