Gastrointestinal mucus constitutes a critical physiological barrier in the gastrointestinal tract. Its highly glycosylated mucin network effectively hinders the transport of particles and drug molecules toward the intestinal epithelium. In oral drug delivery, effectively overcoming this gastrointestinal mucus barrier is essential for achieving efficient drug absorption. On one hand, the continuously secreted mucus layer rapidly clears ineffectively penetrating particles due to its shear-thinning rheological property. On the other hand, macromolecular drugs face significant challenges in cross-mucus diffusion when their molecular size exceeds the mucus mesh pore size. Furthermore, certain small-molecule drugs can also be retained within the mucus layer through physicochemical interactions with its components, or rapidly eliminated by the dynamic turnover of the continuously secreted mucus, consequently leading to reduced drug delivery efficiency. Therefore, enhancing the mucus-penetrating capability of drug molecules is crucial for improving their oral bioavailability. This article systematically reviews the composition, structure, physicochemical properties, and barrier characteristics of gastrointestinal mucus, along with its barrier mechanisms affecting oral drug absorption. Additionally, it discusses nanotechnology-based drug delivery strategies designed to overcome the mucus barrier. The review aims to provide a theoretical basis and design principles for enhancing mucus permeability, improving oral bioavailability, and developing highly efficient mucus-penetrating nano-formulations.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |