Development and evaluation of novel topical formulations containing psoralen for management of psoriasis

Psoriasis is a common genetically determined chronic inflammatory skin disorder affecting 2 – 5% of the population worldwide. Psoralen, an active constituent present in Psoralea corylifolia, has been widely used as traditional medicine for the treatment of various skin disorders. However, the drug delivery system used for administering the herbal medicine to the patient is traditional and out-of-date, resulting in reduced efficacy of the drug. Application of novel drug delivery technology to herbal medicine might increase the efficacy.

In the present study Nano-structured Lipid Carriers (NLCs) containing psoralen were developed and optimized using factorial design. The NLCs were evaluated for mean diameter and surface morphology. The optimized NLCs were incorporated into gel base. In vitro skin irritation and in vivo antipsoriatic activity of prepared formulation were carried out in animal model.

The optimized NLCs were 211 ± 2.11nm in size and were nearly spherical as seen under TEM. Psoralea corylifolia loaded NLC gel showed sustained release of drug with 87% of drug release after 24 hrs of study. In vivo studies indicated that NLCs containing gel formulation significantly improved therapeutic index in controlling orthokeratosis. Moreover no skin irritation was observed with this novel formulation. The findings of this experiment conclusively reveals the promising role of novel herbal gel formulation in the effective treatment of psoriasis.