The proximal part of the colon offers opportunities to prolong the absorption window following oral administration of a drug. In this work, we used computer simulations to understand how the hydrodynamics in the proximal colon might affect the release from dosage forms designed to target the colon. For this purpose, we developed and compared three different models: a completely-filled colon, a partially-filled colon and a partially-filled colon with a gaseous phase present (gas-liquid model).

The highest velocities of the liquid were found in the completely-filled model, which also shows the best mixing profile, defined by the distribution of tracking particles over time. No significant differences with regard to the mixing and velocity profiles were found between the partially-filled model and the gas-liquid model. The fastest transit time of an undissolved tablet was found in the completely-filled model. The velocities of the liquid in the gas-liquid model are slightly higher along the colon than in the partially-filled model. The filling level has an impact on the exsisting shear forces and shear rates, which are decisive factors in the development of new drugs and formulations.

口服药物后，结肠的近端部分提供了延长吸收窗口的机会。在这项工作中，我们使用计算机模拟来了解近端结肠中的流体动力学如何影响针对结肠的剂型的释放。为此，我们开发并比较了三种不同的模型：完全填充的结肠，部分填充的结肠和存在气相的部分填充的结肠（气液模型）。

在完全填充的模型中发现了最高的液体速度，该模型还显示出最佳的混合曲线，该曲线由跟踪粒子随时间的分布确定。在部分填充模型和气液模型之间，在混合和速度分布方面没有发现显着差异。在完全填充的模型中发现了未溶解片剂的最快运输时间。气液模型中沿结肠的液体速度比部分填充模型中的液体速度略高。填充水平对现有剪切力和剪切速率有影响，剪切力和剪切速率是开发新药物和制剂的决定性因素。