[Studies on toxicity of hydrocortisone 17-butyrate 21-propionate -2. Subacute toxicity in rats by subcutaneous administration (author's transl)].

Subacute toxicity of hydrocortisone 17-butyrate 21-propionate (HBP), a new synthetic corticosteroid, was studied in rats, using betamethasone 17-valerate (BV) and hydrocortisone 17-butyrate (HB) as the reference drugs. HBP was subcutaneously injected to rats at the daily doses of 0.08, 0.4, 2.0, 10 and 50 mg/kg for 30 days. BV and HB were also administered at the daily doses of 0.08, 0.4 and 2.0 mg/kg. The recovery test was performed for 4 weeks after administration of HBP, BV and HB. The suppression of body weight gain by HBP was observed at the doses more than 0.08 mg/kg in male and more than 2.0 mg/kg in female rats. In addition, at the doses more than 0.4 mg/kg of HBP induced the dose-dependent symptoms such as decrease in the number of circulating white blood cells, lymphocyte counts and S-ALP level, increase in total cholesterol, GOT and GPT level of serum, and regressive changes in adrenals, lymphatic and hematopoietic tissues. There were fatal cases in rats given 50 mg/kg of HBP. These changes are considered to be common phenomena to other corticosteroids, and less toxic in female than male rats. Changes of symptoms caused by the administration of HBP 2.0 mg/kg were almost recovered after withdrawal. The toxicities of three corticosteroids were in the order of BV greater than HB greater than or equal to HBP in strength. As the result, maximum non-toxic dose of HBP was estimated to be 0.08 mg/kg in female and lower than that in male rats.