Abstract

Layered double hydroxides (LDH) comprise a class of materials that can be either found as natural minerals or can be synthetically prepared. Their structure is composed of a mixture of divalent and trivalent metal cations, forming brucite-like layers, that are neutralized with anions in the interlayer gallery. They have unique physical and chemical characteristics such as: high surface area, large charge density, biocompatibility and exchange capacity. These have attracted attention to the LDHs as potential drug delivery vehicles. Graphene (G) has also attracted the attention to exceptional properties, such as huge surface area, charge density concentration, membrane permeability by piercing mechanism and many others, expanding its use to include biomedical applications, such as drug delivery. Moreover, the possibility of large scale production of exfoliated graphene oxide (GO) sheets from G offered a further opportunity for their use. GO has a high exposed oxygenated surface that allows loading of large number of drugs by different bonding interactions and is dispersible in water. Alendronate sodium is a water soluble nitrogen containing bisphosphonate (nBP) drug, that has low bioavailabilty (< 1 %) due to its low epithelial permeability. It also exhibits gastrointestinal adverse effects. The objective of the work is to create a hybrid nanocomposite of Zn-Al LDH in its nitrate form with G/GO, (G/GO-Zn-Al-NO3 LDH), combining the properties of these structures: membrane permeability and large interacting surface of G or GO, the buffering effect and the capability of the LDH in storing and controlling the drug release. The hybrid nanocomposites incorporated 2% w/w of G or GO with two different M2+/M3+ ratios of LDH, 2:1 and 3:1. They were loaded with the drug by co-precipitation and ion exchange. The samples were characterized by XRD, FTIR, Zetasizer analyzer, and the amount of drug loaded and released were determined by UV/Vis spectroscopy, and the results were compared to those of drug-LDH controls. Samples that have show successful intercalation of the drug in bi-layered arrangement are: co-precipitation samples using M2+/M3+ ratio of 3:1 (drug-LDH, G/GO-LDH), and ion-exchange samples, that don’t incorporate G/GO (drug-LDH), prepared using either M2+/M3+ ratios of 2:1or 3:1. Their loading amounts ranged from 25.4 to 51 % w/w, and they exhibited a sustained release over 24 hours with a release percentages, ranging from 2.1% (1.07 mg) up to 4.2 % (1.52 mg). The other samples showed loading by surface adsorption on brucite-like layers of the LDH and the G or GO. They have drug loading amounts ranging, from 12.4 to 57.3 % w/w. This work demonstrated the potential of G/GO-Zn-Al LDH nanocomposites for sustained drug delivery.

Department

Nanotechnology Program

Degree Name

MS in Nanotechnology

Graduation Date

2-1-2015

Submission Date

January 2016

First Advisor

Ramadan, Adham

Committee Member 1

Gazayerly, Omaima

Committee Member 2

Mamdouh, Wael

Extent

138 p.

Document Type

Master's Thesis

Rights

The author retains all rights with regard to copyright. The author certifies that written permission from the owner(s) of third-party copyrighted matter included in the thesis, dissertation, paper, or record of study has been obtained. The author further certifies that IRB approval has been obtained for this thesis, or that IRB approval is not necessary for this thesis. Insofar as this thesis, dissertation, paper, or record of study is an educational record as defined in the Family Educational Rights and Privacy Act (FERPA) (20 USC 1232g), the author has granted consent to disclosure of it to anyone who requests a copy.

Institutional Review Board (IRB) Approval

Not necessary for this item

Comments

A special appreciation and sincere gratitude to my advisor Prof. Adham Ramadan, for being a tremendous mentor and for his continuous support, patience, and immense knowledge. His guidance helped so much throughout the research, and am really grateful to him for accepting me to work under his supervision. My sincere gratitude to the huge technical support, provided by Mr. Mahmoud Abdel Moez, Mr. Victor and Mr. Emad Farag. I am also very grateful to Mr. Ahmed Omaya for being a supportive friend in my research work and for facilitating a lot of technicalities. Without their help, I wouldn’t have conducted this work. Would like to acknowledge the academic, and grant support provided by the American University in Cairo. I would like to acknowledge the support of my graduate professors, their educational material and advices. I would like to thank my big family: parents, grandparents, sister, brother, aunt, and uncles. Each one of them provided me with emotional support, they were patient and standing out there for me all along. Their prayers and encouraging is what sustained me that far. Last but definitely not least, my colleagues who turned to be best friends ever, who made this experience more fun and smooth. Words are not enough to express how supportive they were throughout my research work, career and on a personal level. Thanks for each and every one of them: Zahraa, Raghda, Alshaima, Yomna, Ruaa and Woroud.

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