Glycans and glycan-based molecules have been used as drugs themselves. The two main functions of these drugs are to either bind protein or inhibit glycosyl degradation. For example, engineered glycans, such as Zanamivir and Oseltamivir have been designed to bind to viral sialidases, which are enzymes that play key roles in viral replication cycles, such as for influenza. With these sialidases inhibited, viral budding and entry into host cells is inhibited. Other drugs, such as Miglitol and Acarbose, serve as therapeutic drugs to people with Type 2 diabetes, as these engineered glycan derivatives bind to glucosidases and amylases to help control patient's blood sugar level.