But until now most hydrophilic and macromolecular drugs like peptides, proteins and polysaccharides need to be injected due to low absorption at mucosal sites.

• 但是直到现在为止,大部分亲水性的大分子药物比如多肽、蛋白质以及多糖等,由于吸收太差,仍然只能采用注射的方式给药。