Biocoating—A Critical Step Governing the Oral Delivery of Polymeric Nanoparticles

Abstract

Decades of research into the topic of oral nanoparticle (NP) delivery has still not provided a clear consensus regarding which properties produce an effective oral drug delivery system. The surface properties—charge and bioadhesiveness—as well as in vitro and in vivo correlation seem to generate the greatest number of disagreements within the field. Herein, a mechanism underlying the in vivo behavior of NPs is proposed, which bridges the gaps between these disagreements. The mechanism relies on the idea of biocoating—the coating of NPs with mucus—which alters their surface properties, and ultimately their systemic uptake. Utilizing this mechanism, several coated NPs are tested in vitro, ex vivo, and in vivo, and biocoating is found to affect NPs size, zeta‐potential, mucosal diffusion coefficient, the extent of aggregation, and in vivo/in vitro/ex vivo correlation. Based on these results, low molecular weight polylactic acid exhibits a 21‐fold increase in mucosal diffusion coefficient after precoating as compared to uncoated particles, as well as 20% less aggregation, and about 30% uptake to the blood in vivo. These discoveries suggest that biocoating reduces negative NP charge which results in an enhanced mucosal diffusion rate, increased gastrointestinal retention time, and high systemic uptake.

Algae-Based Nanoparticles for Oral Drug Delivery Systems

“…Previously, it was shown that negative surface charge correlates with mucoadhesiveness by forming hydrogen bonds with mucins [ 25 ]. Another study showed mucins can attach to negatively charged molecules via positively charged amino acids in the terminal domains [ 26 ]. Yet, it was also demonstrated that loose mucins in the lumen adhere to and coat charged NPs and may neutralize their effective surface charge [ 27 ].…”

Advances in nanomaterial-based targeted drug delivery systems

“…Nanodrug delivery platforms can transport malabsorbed drugs to the gastrointestinal tract and improve oral bioavailability. Coating nanoparticles with biological mucus modify their surface properties and increases the mucosal diffusion rate, gastrointestinal retention time, and systemic absorption ( Azagury et al, 2022 ). Modifying ligands on the surface of nanoparticles can also specifically target the gastrointestinal tract.…”

Synthesis of Lipid Nanoparticles Incorporated with Ferula assa-foetida L. Extract

“…In addition, to determine the potential stability of the obtained lipid nanoparticles, the zeta potential (ZP) was also measured. ZP is one of the key parameters describing the process of particle behavior in suspension and is used to analyze the electrostatic properties of suspensions [34]. It is assumed that the tested material can be considered stable if the absolute value of the zeta potential is greater than −30 mV [35,36].…”