[Studies on the Pharmacology of 6alpha,9-difluoro-11beta-hydroxy-16alpha-methyl-21-valeryloxy-1,4-pregnadiene-3,20-dione (diflucortolon valerate) (author's transl)].

The topical and systemic anti-inflammatory action of 6alpha,9-difluoro-11beta-hydroxy-16alpha-methyl-21-valeryloxy-1,4-pregnadiene-3,20-dione (diflucortolone valerate, Nerisona) was studied in the rat in comparison with fluocortolone, diflucortolone and some other corticoids. In addition the effect of the compounds studied on the following parameters of corticoid activity was examined in the rat: body weight and weights of thymus, spleen and adrenals; blood sugar concentration and liver glycogen content; diuresis and Na+ and K+ elimination with the urine; the binding of diflucortolone and some diflucortolone-21-esters to the cytoplasmic corticoid receptor of the rat's thymus was also determined. In all tests diflucortolone was shown to be a corticoid with very potent topical and systemic action. Diflucortolone valerate showed the same potent anti-inflammatory action on topical application as the unesterified compound. After subcutaneous administration, however, the systemic corticoid action of the valerate was considerably inferior to that of diflucortolone on account of the kinetics of the more lipid soluble ester.