Abstract : Difluprednate (DFBA 6alpha9-difluoro-11beta1721-trihydroxy-14-pregnadiene-320-dione 21-acetate 17-b
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Abstract : Difluprednate (DFBA 6alpha9-difluoro-11beta1721-trihydroxy-14-pregnadiene-320-dione 21-acetate 17-butyrate) is an effective anti-inflammatory agent derived from prednisolone. The present study aimed to evaluate the metabolite profile of DFBA in rabbit ocular tissues after instillation of DFBA ophthalmic emulsion. The high-performance liquid chromatography with radiochemical detection was employed to analyze radioactivity in rabbit ocular tissues that had been instilled with a (3)H-DFBA 0.05 ophthalmic emulsion. At 0.5 and 2 h after instillation DFBA was not detected in the cornea aqueous humor or iris/ciliary body. Instead 21-deacetylated DFBA (DFB) 17-debutylated DFB (DF) and an unknown metabolite were found. The unknown metabolite was identified as de-17-side chain-glucocorticoid metabolite (DF21C) which is a novel glucocorticoid metabolite formed by the scission of the 17-side chain via an unknown metabolic reaction pathway. The K(i) value of DF21C was 5.6 x 10(-7) mol/L indicating very weak glucocorticoid receptor binding of DF21C (approximately 1000-fold less than that of DFBA and DFB).
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