Jain Anekant, Gupta Yashwant, Jain Sanjay K
Pharmaceutics Research Projects Laboratory, Department of Pharmaceutical Sciences, Dr. Hari Singh Gour University, Sagar-470 003 (MP), India.
J Pharm Pharm Sci. 2007;10(1):86-128.
The ability to deliver drugs to the human colon in a specific manner has become feasible over the years. Targeting pharmaceutical drugs to the colon makes it possible to achieve local or systemic drug delivery to this site. To deliver the compounds in a non-degraded form to the lower part of the gastrointestinal tract, they must first of all pass through the stomach, the upper part of the intestine and must use the characteristics of the colon to specifically release the drugs in this part of the digestive tract. Among the different approaches available to achieve targeted drug release to the colon, the use of especially biodegradable polymers holds great promise. This family of natural polymers has great appeal to drug delivery as it is comprised of polymers with a large number of derivatizable groups, a wide range of molecular weights, varying chemical compositions, and, for the most part, low toxicity and biodegradability yet high stability. The most favorable property of these materials is their approval as pharmaceutical excipients. Polysaccharidases are bacterial enzymes that are available in sufficient quantity to be exploited in colon targeting. Bacterial sources of polysaccharidases as well as a detailed treatise of the enzymatic flora of the colonic region is reviewed, followed by a wide range of the polysaccharides which can be used solely for the purpose of colon-specific drug delivery. Present article also discusses few of the mechanisms by which members of the intestinal microbiota degrade complex polysaccharides. A final overview of the various approaches to target drugs to the colon utilizing natural polysaccharides, the limits and the future developments in this field with these natural polymers is discussed which leads to the conclusion that polysaccharides show high potential in achieving colon-specific drug delivery.
多年来，以特定方式将药物递送至人体结肠已成为可行之事。将药物靶向递送至结肠使得在此部位实现局部或全身药物递送成为可能。为了将化合物以未降解的形式递送至胃肠道下部，它们首先必须穿过胃、小肠上部，并且必须利用结肠的特性在消化道的这一部分特异性释放药物。在可用于实现药物靶向释放至结肠的不同方法中，使用特别是可生物降解的聚合物具有很大的前景。这类天然聚合物对药物递送具有很大吸引力，因为它由具有大量可衍生化基团、广泛分子量范围、不同化学组成且在大多数情况下低毒性、可生物降解但稳定性高的聚合物组成。这些材料最有利的特性是它们被批准作为药物辅料。多糖酶是细菌酶，其数量充足，可用于结肠靶向。本文综述了多糖酶的细菌来源以及结肠区域酶菌群的详细论述，随后介绍了一系列可仅用于结肠特异性药物递送目的的多糖。本文还讨论了肠道微生物群成员降解复杂多糖的一些机制。最后概述了利用天然多糖将药物靶向递送至结肠的各种方法、该领域的局限性以及这些天然聚合物的未来发展，得出的结论是多糖在实现结肠特异性药物递送方面具有很高的潜力。
