2.10. In Vivo Antipsoriatic Activity

To evaluate the potency of developed MTX-NPs loaded hydrogel for antipsoriatic activity, an Imiquimod (IMQ) induced psoriatic plaque model was used [50]. After approval from the Bio-Ethical Committee (BEC) Quaid-i-Azam University Islamabad, Pakistan under reference no. (#BEC-FBS-QAU2020–260), antipsoriatic studies were performed. Male BALB/c mice of 6–8 weeks old, with a weight ranging 20–30 g, were utilized to conduct antipsoriatic activity. Mice were kept under standard laboratory environments of temperature and humidity, i.e., 25 ± 2 °C and 55 ± 55% RH with unrestricted availability of food and water. The dorsal backside of mice was shaved using a Sterling–2 hair clipper prior to the study. The mice were divided into five groups. Psoriasis or hyperplasia was induced, except in group 1, by topically applying marketed imiquimod (IMQ) cream (Aldara^TM 5% cream w/w, (MEDA AB, Pharma) on the dorsal side’s shaved skin and right ear of healthy mice with an amount equal to 62.5 mg for successive 7 days [51]. From day 8, the group 3, 4 and 5 were treated with free MTX hydrogel, marketed cream and MTX-NPs loaded hydrogel, respectively. The severity of inflammation was measured by psoriasis area severity index (PASI) [1], to check parameters such as erythema, scaling and ear thickness. The treatment continued for the 10 consecutive days after psoriasis induction. The intensity of psoriatic symptoms such as thickness, redness and scaling were assessed again as none (0), mild (1), moderate (2), severe (3) and very severe (4) and compared with scores before treatment. These results were drawn by taking time on x-axis and PASI score (0–4) along y-axis.