[Nanocarrier in veterinary medicine - a pilot study for the treatment of feline hyperthyroidism with a nano-carrier based thiamazole ointment].

The oral treatment of feline hyperthyroidism with antithyroid drugs often results in gastrointestinal side effects (10-20%). To date only oral formulations are approved although the oral application is not tolerated by all cats. Transdermal therapy can be an alternative. Nanocarriers could be used to ensure adequate transport of active agents through the skin. The present pilot study investigated the efficacy and safety of a novel dermal formulation of thiamazole for the treatment of feline hyperthyroidism. For the first time, amphiphilic dendritic core-multishell-nanocarriers were used. Cats with T4 values ≥ 4.0 µg/dl or a T4 value from 3.0-4.0 µg/dl and defined clinical findings were recruited. The euthyroid range for the T4 value was defined from ≥ 0.8 and ≤ 4.0 µg/dl. A total of 24 hyperthyroid cats were included and treated with thiamazole ointment for three weeks (24 cats) up to eight weeks (12 cats). The treatment success was 50% after three weeks and 41,7% after eight weeks. Cats that were within the euthyroid range required after three weeks a mean total dose of 1,09 mg/kg/d (0,68-1,7 mg/kg/d, 12/24) and after eight weeks 1,65 mg/kg/d (1,49-2,04 mg/kg/d, 5/12). No side effects were observed during the three resp. eight-week study period. Variations of the T4 value in companion cats in the same household were comparable to those of an independent control group. Thiamazole ointment based on nanocarriers is suitable for the treatment of feline hyperthyroidism.