pH-dependent ileocolonic drug delivery systems rely on the sharp pH peak reaching 7.2–7.7 usually found in the ileum of healthy individuals and patients with colonic diseases. The pH dependency of novel drug delivery systems should first be evaluated in in vitro dissolution tests mimicking the human gastrointestinal (GI) pH profile and buffer composition. When proven successful in vitro, the clinical applicability of a novel system should be confirmed in humans. Various methods have been published to verify ileocolonic drug delivery in humans. Of those, we recommend the caffeine-sulfasalazine method and the dual stable isotope approach.

中文翻译：

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pH 依赖性回结肠药物递送，第一部分：新型系统的体外和临床评估。

pH 依赖性回结肠药物递送系统依赖于通常在健康个体和结肠疾病患者的回肠中发现的尖锐 pH 峰值，该峰值达到 7.2-7.7。新型药物递送系统的 pH 依赖性应首先在模拟人胃肠 (GI) pH 曲线和缓冲液组成的体外溶出度试验中进行评估。当在体外证明成功时，新系统的临床适用性应在人体中得到证实。已经发表了各种方法来验证人体回结肠药物递送。其中，我们推荐咖啡因-柳氮磺吡啶法和双重稳定同位素法。