Silica nanoparticles on the oral delivery of insulin

ABSTRACT

Introduction: When intravenous or subcutaneous administration of insulin, various side effects or possible risks have been reported. Oral administration of insulin has significant advantages of convenience, painless and mimetic endogenous insulin pathway, and thus it presents patients compliance, protects pancreatic β cells and lessens adverse effects caused by long-term injection. This challenging oral delivery of insulin can be achieved by promising silica nanoparticles (SNs), especially mesoporous silica nanoparticles (MSNs), with controllable morphology and high loading efficiency. This review presents the synthesis and physiological behaviors of SNs such as in vivo and in vitro degradation, absorption, distribution, and excretion, as well as preparations of oral insulin based on SNs. As well, this review will provide insights for innovative oral delivery of SNs and insulin.

Areas covered: Promising SNs and MSNs have gained interests for application in oral drug delivery of insulin.

Expert opinion: After synthesis under proper conditions and methods, promising SNs with controllable structure and suitable stability can be synthesized. By improving permeability and penetration, achieving controlled release and adjusting physiological processes, functionalization on SNs by active groups, molecules, or polymers is necessary for oral delivery of insulin.

KEYWORDS:

• Insulin
• silica nanoparticles
• oral delivery
• therapeutic protein and peptide

Article highlights

●The review briefly describes oral delivery of insulin based on silica nanoparticles (SNs) and mesoporous silica nanoparticles (MSNs).

●There are various advantages of oral insulin compared with intravenous or subcutaneous injection. As well, compared with other formulations, SNs show special and advantageous characteristics and thus are suitable for oral delivery of insulin.

●For large porous structure and loading space, suitable templates and swelling agents can be applied.

●Proper structural properties or surface chemistry of SNs and loading conditions are important for insulin physical loading.

●Biodegradable SNs with insulin can be absorbed, distributed and excreted in vivo.

●Applied of oral insulin based on nonporous or mesoporous SNs have been well developed, and these SN preparations can collaborate with various bioactive polymers and formulations.

This box summarizes key points contained in the article.

Acknowledgments

We greatly thank Amanda Pearce for language editing

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer declaration of Interest

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China under Grant No. 81503014; and the Doctoral Fund of Liaoning Province under Grant No. 201601215.