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Development of Drug Delivery Systems Incorporating Cellulose Nanocrystals

Omita, Antony Apollo Hawii; (2023) Development of Drug Delivery Systems Incorporating Cellulose Nanocrystals. Doctoral thesis (Ph.D), UCL (University College London). Green open access

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Abstract

Cellulose nanocrystals (CNCs) are a nanomaterial derived from cellulosic materials by acid hydrolysis under specific conditions. The starting material used and the specific conditions employed during the hydrolysis, will influence the properties of the CNCs produced. Previous studies have shown that CNCs possess numerous intrinsic properties that would be beneficial for application as an excipient. Among these properties are that they are biodegradable, biocompatible, non-toxic, have good thermal stability as well as a low cost of production. Further, CNCs have been shown to possess superior mechanical properties with a modulus range of 110 – 180 GPa. In this study we have demonstrated that when used as a tabletting excipient it is possible to produce tablets that satisfy the standards set in the British Pharmacopoeia in relation to uniformity of the tablets as well as friability. Additionally, the compacts produced had a mean hardness of 67 N which exceeded the requirements outlined in previous studies. Comparison of the drug release profile of CNC-based and MCC-based tablets, and determination of the similarity factor between the two release profiles, showed that the two tablet batches offered a similar release profile – this was based on having a similarity factor of 66%. As part of this work we have also investigated the application of CNCs as a nanocomposite in both nanofibers as well as extruded filaments. Rheological analysis of the electrospinning solutions used to produce the nanofibers demonstrated that CNCs can be used as a viscosity enhancer – higher CNC loadings were founds to produce electrospinning solutions with a higher viscosity. Additionally, through the AFM nanomechanical analysis we were able to show that CNC loading influenced the modulus of the nanofibers produced. The enhancement in nanofiber modulus was dependent on the amount of CNC loading – higher loadings resulted in stronger nanofibers. The good thermal stability of CNCs make them an ideal candidate for use as a nanocomposite in filaments processed by hot-melt extrusion. In this study we demonstrated that CNCs can be processed at temperatures of 200 °C. Further, mechanical assessment of the filaments produced showed that the loading of CNCs into the filaments was able to improve their flexibility and hardness. It was possible to achieve these enhancements in the mechanical properties of the filaments event at low CNC loadings such as 5% (%w/w).

Type: Thesis (Doctoral)
Qualification: Ph.D
Title: Development of Drug Delivery Systems Incorporating Cellulose Nanocrystals
Open access status: An open access version is available from UCL Discovery
Language: English
Additional information: Copyright © The Author 2023. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request.
Keywords: Cellulose nanocrystals, CNCs, Microcrystalline cellulose, MCC, Polyvinyl alcohol, PVA, Electrospinning, tableting, hydrogel, hot-melt extrusion, hme, 3D printing, excipient
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > UCL School of Pharmacy
URI: https://discovery-pp.ucl.ac.uk/id/eprint/10174041
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