Enhanced Delivery of Methotrexate for Scalp Psoriasis Treatment via Nanosuspension Hair Dye: A Box-Behnken Optimization Approach

Background: Scalp psoriasis affects a significant portion of psoriasis patients and can be exacerbated by conventional hair dyes. This study aimed to develop a dual-purpose nanosuspension hair dye formulation containing methotrexate for simultaneous treatment and hair coloring. Methods: Methotrexate nanosuspensions were prepared using the precipitation-ultrasonication method, incorporating beetroot powder as a natural coloring agent. The formulation was characterized using FT-IR, DSC, particle size and zeta potential measurements, SEM, in vitro drug release studies, pH determination, and drug content analysis. The coloring ability and color stability were also evaluated. Results: FT-IR and DSC confirmed drug-excipient compatibility. The nanosuspension had a particle size of 154 nm and a zeta potential of -29 mV. SEM revealed a generally spherical particle morphology. In vitro drug release showed 86% release in 1hour. The formulation pH was 5.89, and the drug content was 96%. The formulation effectively colored grey hair reddish and enhanced the luster of black hair. The color was stable against sunlight but faded after 6-8 washes with gentle shampoo. Conclusion: A methotrexate-loaded nanosuspension hair dye formulation is feasible and shows potential for treating scalp psoriasis while coloring hair.