Assessment of the Mucoadhesion and Mucopermeation of Emulsifying Systems Containing Copaiba Oil on the Intestinal Mucosa

Mucopenetrating systems are drug delivery platforms designed to overcome the intestinal mucus barrier, facilitating access to epithelium and enhancing the bioavailability of lipophilic compounds. Copaiba oil (CO) is a compound displaying broad therapeutic potential but low aqueous solubility, which limits its bioavailability. This study aimed to assess how two CO-loaded delivery systems, an emulsion (EM) and a self-emulsifying system (SE), interact with the intestinal mucus layer and how effectively they permeate it. Thus, interactions with mucin and porcine intestinal mucosa were evaluated via oscillatory rheometry, by determining rheological synergism, and the in vitro and ex vivo mucoadhesion assays. The retention of the emulsion systems on the intestinal mucosa was also assessed, along with mucopermeation, using Transwell inserts coated with porcine intestinal mucus and mucin solution. Rheological analysis demonstrated a significant interaction between SE and mucin, evidenced by positive rheological synergism, whereas EM showed limited interaction. In mucoadhesion studies, EM behavior was primarily associated with its higher consistency, while SE exhibited more specific interactions with mucin. Ex vivo retention studies demonstrated greater retention of EM on the intestinal mucosa. In contrast, SE showed superior permeation through the mucus layer in mucopermeation assays, a behavior attributed to the presence of PEG 400. Overall, SE exhibited a more favorable balance between mucoadhesion and mucus penetration than EM. The SE demonstrated enhanced mucopermeation while maintaining adequate interaction with intestinal mucus, suggesting its potential as a promising oral delivery platform for improving the intestinal transport and bioavailability of copaiba oil.