New materials for drug delivery

• Main Author: Nor Huda Mohd.
• Other Authors: Andrew Clive Grimsdale
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Materials::Biomaterials
• Online Access: http://hdl.handle.net/10356/36173
• Institution: Nanyang Technological University

Dendrimers have been explored for use in drug delivery due to their attractive properties. By varying the branching units and the surface functional groups of dendrimers, it is possible to precisely control the molecule size, shape, polarity, and solubility. Although dendrimers offer many advantages, most dendrimers have certain cytotoxicity from the in vivo studies done by a number of researchers. Phenylene dendrimers however are biologically inert, hence they are nontoxic. Hydroxyapatite (HA), on the other hand, is well known for its excellent biocompatibility which makes it suitable to be used for drug delivery applications. With these ideas in mind, binding HA with phenylene dendrimer was developed as new materials for drug delivery. The aims of this project are to synthesise alkyne with polyethylene glycol (PEG) attached, and subsequently binding it to the surface modified HA. However, alkyne with diethylene glycol attached (alkyne) was synthesised instead to serve as a controlled model study for future investigation of dendrimer functionalised with PEG. The synthesis of the alkyne was achieved through alkylation by SN2 reaction, and Sonogashira coupling. Pyrophosphoric acid (PPA) was used to modify the surface of the HA so as to obtain the hydroxyl groups on the surface. These hydroxyl groups will then be used to react with the carboxyl group of the alkyne. Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared (FTIR) were used to characterise the products obtained. The objectives of the project were partly achieved with the success of the alkyne synthesis. The attachment of the hydroxyl groups to the carboxyl group of the alkyne was not successful due factors such as the use of incorrect reaction method and the presence of moisture on the surface of the HA. Nevertheless, this has provided an insight for further future works. Some recommendations for future works include modifying the surface of the HA with poly(vinyl alcohol) and studying the moisture effect on the surface attachment.