title: The Role of Polydimethylsiloxane in the Molecular Structure of Silica Xerogels Intended for Drug Carriers.
abstract: The aim of this study was to prepare and examine polymer/oxide xerogels with metronidazole (MT) as delivery systems for the local application of a drug to a bone. The nanoporous SiO2-CaO and PDMS-modified SiO2-CaO xerogel materials with different amounts of the polymer, polydimethylsiloxane (PDMS), were prepared by the sol-gel method. Characterization assays comprised the analysis of the composite materials by using Fourier transform infrared spectroscopy (FTIR), determining the specific surface area of solids (BET), using X-ray powder diffraction (XRD) and scanning electron microscope (SEM) techniques, and further monitoring in the ultraviolet and visible light regions (UV-Vis) of the in vitro release of the drug (metronidazole) over time. According to these results, the bioactive character and chemical stability of PDMS-modified silica xerogels have been proven. The release of MT from xerogels was strongly correlated with the composition of the matrix. In comparison with the pure oxide matrix, PDMS-modified matrices accelerated the release of the drug through its bigger pores, and additionally, on account of weaker interactions with the drug. The obtained results for the xerogel composites suggest that the metronidazole-loaded xerogels could be promising candidates for formulations in local delivery systems particularly to bone.
authors.affiliation: Department of Physical Chemistry, Medical University of Gdańsk, al. gen. J. Hallera 107, 80-416 Gdańsk, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Czarnobaj
keywords: Drug delivery systems; Ormosils; Sol-gel method
references.citation: J Biomed Mater Res. 1990 Jun;24(6):721-34
references.pmid: 2361964
references.citation: J Mater Sci Mater Med. 2002 Nov;13(11):1015-20
references.pmid: 15348170
references.citation: J Biomed Mater Res B Appl Biomater. 2008 Oct;87(1):114-20
references.pmid: 18437709
references.citation: J Mater Sci Mater Med. 2009 Sep;20(9):1795-801
references.pmid: 19404723
references.citation: Biomatter. 2013 Apr-Jun;3(2):null
references.pmid: 23512012
references.citation: Biomaterials. 2006 May;27(15):2907-15
references.pmid: 16448693
references.citation: Biomaterials. 2002 Aug;23(15):3113-22
references.pmid: 12102182
references.citation: Pharm Dev Technol. 2012 Nov-Dec;17(6):697-704
references.pmid: 21480825
references.citation: J Biomed Mater Res B Appl Biomater. 2007 Apr;81(1):274-82
references.pmid: 17106889
references.citation: J Mater Sci Mater Med. 2014 Mar;25(3):657-68
references.pmid: 24338267
references.citation: Pharm Dev Technol. 2013 Mar-Apr;18(2):377-83
references.pmid: 22107265
references.citation: Biomaterials. 2006 Mar;27(7):964-73
references.pmid: 16102812