Neriproct: Its anti-inflammatory effect on an experimentally induced hemorrhoid model in the rat

Several glucocorticoids as a cream formulation were applied to the recto-anus of the crotonoil-induced hemorrhoid rat. Among the steroids tested, i.e. diflucortolone valerate (DFV), prednisolone (PS), hydrocortisone caproate (HC), and hydrocortisone (H), DFV was found to suppress inflammation most effectively. The effect of DFV was not affected by combination with lidocaine. In this model, the analgesic effect of lidocaine was apparently prolonged by an increase of the threshold for pain by the anti-inflammatory effect of DFV. This additive effect is regarded as a merit of the combination in Neriproct®. Therapeutic effects of Neriproct® and several anti-hemorrhoid drugs were also examined by using a hemorrhoid model with abrasive irritation compared to those obtained by the croton-oil model. In both models, efficacy of Neriproct® was superior to that of the other drugs such as Scheriproct®, Proctosedyl®, Posterisan forte®, Borraginol N®, Posterisan® and Borraza G®. Microscopic observation showed that destruction of the mucus epithelium, necrosis of the mucus layer, infiltration of inflammatory cells and vasodilatation in the croton-oil model were also suppressed markedly by Neriproct® application. No difference was observed in the efficacy between the cream and suppository formulation of Neriproct®. Suppression of wound healing was found with a dosage of DFV lower than those of PS, HC and H. However, the efficacy ratio of the wound-healing suppression and anti-inflammation of DFV was the largest among the steroids tested.