A NEW ANTI-INFLAMMATORY ACTIVITY TEST FOR CORTICOSTEROIDS. THE FORMALIN-FILTERPAPER PELLET METHOD

Abstract

The formalin-filterpaper-pellet method has been standardized as a quantitative anti-inflammatory assay. This is based on the inhibition of granuloma produced by the subcutaneous implantation of the formalin-soaked filterpaper pellets into the adrenalectomized rats. The ideal concentration of formalin is 7%, and the optimal duration for the pellet implantation till autopsy is 6 days. Bilateroventral regions are recommendable as the implantation sites of the pellet for good development of granuloma.This method is superior in accuracy and simplicity, to the cotton ball method based on the similar principle. Reproducibility of the tests for hydrocortisone acetate is satisfiable in terms of dose-response regressions.Comparative assays of prednisolone and dexamethasone, using hydrocortisone acetate as a standard, indicate a potency ratio to the standard of 3 (range 1.8 to 5.3) for prednisolone and of 32 (range 24.8 to 41.2) for dexamethasone, suggesting the usefulness of this method as a standard assay procedure.