Novel Materials for Stabilizing Pickering Emulsions and Their Potential Applications in Drug Delivery
Creators: name: Huang, Zhiwei
Publisher: name: University of Surrey
Year: 2023

description: Pickering emulsions for drug delivery applications have gained increasing attention over recent
description: years because of their low toxicity, high stability, and large stabilizer selectivity. However, diverse
description: drug delivery routes in the human body pose challenges, such as the harsh environment of oral
description: enzymes or stomach acid for oral therapeutics, unstable controlled drug release in parenteral
description: drug administration and low bioavailability in topical drug use due to low drug permeability
description: and retention. This thesis aims to develop and evaluate novel Pickering emulsion systems for
description: applications in drug delivery. Three novel Pickering emulsion systems have been introduced
description: using DI-water as the continuous phase and sunflower oil as the dispersed phase.<br>
description: <br>
description: Pickering emulsions with a narrow size distribution were prepared using biocompatible
description: carboxylated nanodiamond (ND) nanoparticles for the first time. Membrane emulsification
description: and probe sonication were utilized to produce oil droplets with various sizes. The resulting
description: ND-stabilized Pickering emulsions exhibited remarkable stability against mechanical vibrations
description: and long-term storage for up to one year, and across a broad pH range. These characteristics
description: make them promising for use in oral drug delivery applications.<br>
description: <br>
description: Synthetic two-dimensional (2D) peptide assemblies, composed of triblock oligoglycine
description: (2T), were utilized to stabilize Pickering emulsions. The lamellar structure and thermodynamic
description: behavior of the assemblies at the oil/water interface and in the liquid phase were investigated.
description: Because of the protonation and deprotonation of the terminal amino groups of the oligoglycine,
description: the emulsion remained stable at pH 7 but became destabilized at slightly lower pH levels. The
description: synthetic peptide amphiphile is a novel stabilizer to stabilize Pickering emulsions, which holds
description: significant potential for biomedical applications, particularly for the parenteral route.<br>
description: <br>
description: 2T-modified ND particles were fabricated by covalently bonding the carboxyl group on
description: ND with the terminal amino group of 2T, and were utilized to stabilize Pickering oil-in-water
description: emulsions. These emulsions exhibit a better stability over three months of storage compared
description: to ND or 2T emulsions. As a model system, Pickering emulsions were evaluated for the
description: encapsulation of organic components for ocular drug delivery for the first time. According
description: to an ex vivo Bovine Corneal Permeability and Opacity test, there is no significant toxicity
description: difference between the ND-2T Pickering emulsions and PBS buffer. The retention of ND-2T
description: Pickering emulsions on corneal tissue is significantly strengthened because of the positively charged terminal amino group of 2T. The superior stability and retention of ND-2T Pickering emulsions on corneal tissue demonstrated in this research suggest their potential application in ocular drug delivery, which could improve patient outcomes.<br>