CASE PRESENTATION: We described a 60-year-old man diagnosed with COVID-19 infection and later presented with a two-week history of myalgia, progressive limb weakness, and dysphagia. He had a Creatinine Kinase (CK) level of more than 10,000 U/L, was strongly positive for anti-signal recognition particle (SRP) and anti-Ro52 antibody, and a muscle biopsy revealed a paucity-inflammation necrotizing myopathy with randomly distributed necrotic fibers, which was consistent with necrotizing autoimmune myositis (NAM). He responded well clinically and biochemically to intravenous immunoglobulin, steroids and immunosuppressant and he was able to resume to his baseline.

SIGNIFICANCE: A strong need exists for the development of transdermal patch having improved bioavailability at the site of action with fewer side effects at off-target organs.

METHODS: The patches were physically characterized by texture analysis (color, flexibility, smoothness, transparency, and homogeneity), in vitro dissolution test and FTIR analysis. Furthermore, functional properties essential for TDDS, in vitro percentage of moisture content, percentage of water uptake, in vitro permeation by following different kinetic models, in vivo drug content estimation and skin irritation were determined using rabbit skin.

RESULTS: The optimized patches were soft, of uniform texture and thickness as well as pliable in nature. Novel transdermal patch showed ideal characteristics in terms of moisture content and water uptake. FTIR analysis confirmed no interaction between TZH and cellulose acetate phthalate (CAP). The patch showed sustained release of the drug which increased the availability of short acting TZH at the site of action. The patch also showed its biocompatibility to the in vivo model of rabbit skin.