Fig. 4From: Mucus interaction to improve gastrointestinal retention and pharmacokinetics of orally administered nano-drug delivery systemsIllustration of the mucus-interacting methods employed for successful oral drug delivery: mucoadhesive, mucus-penetrating (densely layered uncharged surface coating and evenly distributed positive/negative surface charges) and mucolytic (conjugated and released mucolytic enzymes)Back to article page