Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/78381
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Type: Journal article
Title: Tuning drug loading and release properties of diatom silica microparticles by surface modifications
Author: Bariana, M.
Aw, M.
Kurkuri, M.
Losic, D.
Citation: International Journal of Pharmaceutics, 2013; 443(1-2):230-241
Publisher: Elsevier Science BV
Issue Date: 2013
ISSN: 0378-5173
1873-3476
Statement of
Responsibility: 
Manpreet Bariana, Moom Sinn Aw, Mahaveer Kurkuri, Dusan Losic
Abstract: Diatomaceous earth (DE), or diatomite silica microparticles originated from fossilized diatoms are a potential substitute for its silica-based synthetic counterparts to address limitations in conventional drug delivery. This study presents the impact of engineered surface chemistry of DE microparticles on their drug loading and release properties. Surface modifications with four silanes, including 3-aminopropyltriethoxy silane (APTES), methoxy-poly-(ethylene-glycol)-silane (mPEG-silane), 7-octadecyltrichlorosilane (OTS), 3-(glycidyloxypropyl)trimethoxysilane (GPTMS) and two phosphonic acids, namely 2-carboxyethyl-phosphonic acid (2 CEPA) and 16-phosphono-hexadecanoic acid (16 PHA) were explored in order to tune drug loading and release characteristics of water insoluble (indomethacin) and water soluble drugs (gentamicin). Successful grafting of these functional groups with different interfacial properties was confirmed using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Thermogravimetric analysis (TGA) was applied to determine the amount of loaded drugs and UV-spectrophotometry to analyse in vitro drug release from modified DE microparticles. Differences in drug release time (13–26 days) and loading capacity (14–24%) were observed depending on functional groups on the surface of DE microparticles. It was found that hydrophilic surfaces, due to the presence of polar carboxyl, amine or hydrolyzed epoxy group, favor extended release of indomethacin, while the hydrophobic DE surface modified by organic hydrocarbons gives a better sustained release profile for gentamicin. This work demonstrates that by changing surface functionalities on DE microparticles, it is possible to tune their drug loading and release characteristics for both hydrophobic and hydrophilic drugs and therefore achieve optimal drug delivery performance.
Keywords: Diatomite; Diatomaceous earth; Porous materials; Surface modifications; Drug delivery; Indomethacin; Gentamicin
Rights: Crown Copyright © 2012 Published by Elsevier B.V. All rights reserved.
RMID: 0020124846
DOI: 10.1016/j.ijpharm.2012.12.012
Grant ID: http://purl.org/au-research/grants/arc/LP0989229
http://purl.org/au-research/grants/arc/FT110100711
Appears in Collections:Chemical Engineering publications

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