Macropored microparticles with a core–shell architecture for oral delivery of biopharmaceuticals
Microparticles (MPs) have been extensively researched as a potential drug delivery vehicle. Here, we investigated the fabrication of MPs with pH-responsive macropores and evaluated their potential applicability in developing solid oral drug formulations. Our previous study showed that macropored MPs, made of Eudragit® L100-55, could encapsulate 100 nm, 1 µm, and 4 µm sized fluorescent beads—model drugs that are mimicking vaccines, bacteria, and cells. In the present study, closed-pored MPs after freeze-drying were coated with a gastric soluble Eudragit® EPO layer to protect MPs in the simulated pregastric environment. Subsequently, drug encapsulated MPs maintained their intact closed-pored structure in the simulated gastric environment and exhibited a rapid release in the simulated intestine environment. Our MP system was found to provide a significantly higher level of protection to the encapsulated lactase enzyme compared to the control sample (i.e. without using MPs). Real-time fluorescence microscopy analysis showed that macropored MPs released encapsulated drugs in a burst-release pattern and in a size-independent manner. This work shows that our proposed EPO-coated MPs with pH-responsive macropores can meet the challenges posed by the multiple physiological environments of the digestive tract and be used in developing highly effective solid oral drug/vaccine formulations.
KeywordsOral delivery Microparticles Macropore Digestive tract pH
This work was supported by the Bill & Melinda Gates Foundation (OPP1061366), Alberta Innovates Technology Futures (AIF200900279), and University of Alberta.
Compliance with ethical standards
Conflict of interest
All the authors declare that they have no conflict of interest.
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