Comparative assessment of the effectiveness of new cream test samples with refined naftalan oil on an experimental model of psoriasis

Psoriasis remains a significant challenge in modern dermatology, necessitating the development of new effective treatments. For over a century, Naftalan-based medicinal products have been utilized in the treatment of inflammatory skin diseases. Considering the known limitations and the therapeutic potential of refined Naftalan oil (RNO), new topical pharmaceutical forms – dermatological creams – were developed and investigated. The aim of the work – to evaluate the efficacy of new test samples (TS) of creams containing refined Naftalan oil in mono-formulation and in combination with drotaverine compared to a topical corticosteroid, hydrocortisone, on an experimental model of psoriatic skin lesions in mice. This study presents the pharmacological evaluation of new TS creams on a model of imiquimod-induced psoriasiform skin lesions in BALB/c mice, induced through a 9-day topical application of IMQ. The creams under investigation included: 10% RNO; 10% RNO combined with 2% drotaverine; and 10% vaseline oil combined with 2% drotaverine. Their efficacy was compared to a reference preparation – a cream containing 1% hydrocortisone butyrate. Therapeutic efficacy was assessed using the modified PASI index on days 7, 14, and 21 of treatment. The pharmacological study results demonstrated that the TS containing 10% RNO combined with 2% drotaverine showed the highest therapeutic efficacy among the tested creams. On day 21 of treatment, the modified PASI index was Me (25%–75%) = 2.0 (1.0–3.0), whereas the TS with vaseline oil combined with drotaverine exhibited moderate efficacy, outperforming the monocomponent cream with 10% RNO. The TS with 10% RNO combined with 2% drotaverine showed efficacy comparable to the reference preparation – a cream with hydrocortisone butyrate. The obtained data highlight the potential for further in-depth pharmacological studies of TS with 10% RNO combined with the phosphodiesterase type IV inhibitor, drotaverine, to investigate its pharmacodynamics. The combination of these active pharmaceutical ingredients in this cream may provide a synergistic effect, leading to more effective reduction of inflammation and skin restoration in experimental psoriasis.