Chapter 19: Carbohydrate-Based Drugs on the Market: Overview and Future Directions

The importance of carbohydrates in cellular physiology has been well known to biologists and biochemists for over two centuries. Nevertheless, these essential molecules have been living in the shadow of proteins and nucleic acids until the last decades, when their pivotal role in cell to cell and cell to pathogen interaction has started to emerge. This renaissance in glycobiology has led to an increasing interest toward the pathophysiological mechanisms in which carbohydrates take part, with the ultimate aim of discovering novel spots for therapeutic intervention. Although current research in structural biology has successfully unraveled many cellular processes in which carbohydrates are directly involved, drug discovery has not moved at the same speed in producing new carbohydrate-based drugs. This is not surprising, considering the complex chemical nature of sugars; indeed carbohydrates are challenging and synthetically demanding substrates, which in many cases require complex multistep synthesis, making it difficult to create libraries of compounds to be tested in a classical pharmaceutical approach. Besides, they are usually endowed with poor pharmacokinetic abilities, being unable to be passively absorbed at an intestinal level, but at the same time possessing a high renal clearance causing low plasmatic half-life if administered parenterally. Despite these drawbacks, several drugs, containing carbohydrate moieties essential for their activity, are present on the market, often representing the first choice for the treatment of a broad range of pathologies including bacterial, viral and micotic infections, tumors, diabetes, blood coagulation disorders and epilepsy.