Pharmaceutical characterization of solid and dispersed carbon nanotubes as nanoexcipients

Marina V Ivanova1, Constanze Lamprecht1, M Jimena Loureiro1, J Torin Huzil1,2, Marianna Foldvari11School of Pharmacy, 2Faculty of Applied Mathematics, University of Waterloo, Waterloo, ON, CanadaBackground: Carbon nanotubes (CNTs) are novel materials with considerable potential in many areas related...

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Autores principales:	Ivanova MV, Lamprecht C, Loureiro MJ, Huzil JT, Foldvari M
Formato:	article
Lenguaje:	EN
Publicado:	Dove Medical Press 2012
Materias:	Medicine (General) R5-920
Acceso en línea:	https://doaj.org/article/9698c18bd602468981510294b5d67545
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spelling	oai:doaj.org-article:9698c18bd602468981510294b5d675452021-12-02T06:38:00ZPharmaceutical characterization of solid and dispersed carbon nanotubes as nanoexcipients1176-91141178-2013https://doaj.org/article/9698c18bd602468981510294b5d675452012-01-01T00:00:00Zhttp://www.dovepress.com/pharmaceutical-characterization-of-solid-and-dispersed-carbon-nanotube-a9147https://doaj.org/toc/1176-9114https://doaj.org/toc/1178-2013Marina V Ivanova1, Constanze Lamprecht1, M Jimena Loureiro1, J Torin Huzil1,2, Marianna Foldvari11School of Pharmacy, 2Faculty of Applied Mathematics, University of Waterloo, Waterloo, ON, CanadaBackground: Carbon nanotubes (CNTs) are novel materials with considerable potential in many areas related to nanomedicine. However, a major limitation in the development of CNT-based therapeutic nanomaterials is a lack of reliable and reproducible data describing their chemical and structural composition. Knowledge of properties including purity, structural quality, dispersion state, and concentration are essential before CNTs see widespread use in in vitro and in vivo experiments. In this work, we describe the characterization of several commercially available and two in-house-produced CNT samples and discuss the physicochemical profiles that will support their use in nanomedicine.Methods: Eighteen single-walled and multi-walled CNT raw materials were characterized using established analytical techniques. Solid CNT powders were analyzed for purity and structural quality using thermogravimetric analysis and Raman spectroscopy. Extinction coefficients for each CNT sample were determined by ultraviolet-visible near infrared absorption spectroscopy. Standard curves for each CNT sample were generated in the 0&ndash;5 &micro;g/mL concentration range for dispersions prepared in 1,2-dichlorobenzene.Results: Raman spectroscopy and thermogravimetric analysis results demonstrated that CNT purity and overall quality differed substantially between samples and manufacturer sources, and were not always in agreement with purity levels claimed by suppliers. Absorbance values for individual dispersions were found to have significant variation between individual single-walled CNTs and multi-walled CNTs and sources supplying the same type of CNT. Significant differences (P &lt; 0.01) in extinction coefficients were observed between and within single-walled CNTs (24.9&ndash;53.1 mL&bull;cm-1&bull;mg-1) and multi-walled CNTs (49.0&ndash;68.3 mL&bull;cm-1&bull;mg-1). The results described here suggest a considerable role for impurities and structural inhomogeneities within individual CNT preparations and the resulting spectroscopic properties of their dispersions.Conclusion: Raw CNT materials require thorough analytical workup before they can be used as nanoexcipients. This applies especially to the determination of CNT purity, structure, and concentration. The results presented here clearly demonstrate that extinction coefficients must be determined for individual CNT preparations prior to their use.Keywords: carbon nanotubes, pharmaceutical characterization, Raman spectroscopy, thermogravimetric analysis, ultraviolet-visible near infrared spectroscopyIvanova MVLamprecht CLoureiro MJHuzil JTFoldvari MDove Medical PressarticleMedicine (General)R5-920ENInternational Journal of Nanomedicine, Vol 2012, Iss default, Pp 403-415 (2012)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine (General) R5-920
spellingShingle	Medicine (General) R5-920 Ivanova MV Lamprecht C Loureiro MJ Huzil JT Foldvari M Pharmaceutical characterization of solid and dispersed carbon nanotubes as nanoexcipients
description	Marina V Ivanova1, Constanze Lamprecht1, M Jimena Loureiro1, J Torin Huzil1,2, Marianna Foldvari11School of Pharmacy, 2Faculty of Applied Mathematics, University of Waterloo, Waterloo, ON, CanadaBackground: Carbon nanotubes (CNTs) are novel materials with considerable potential in many areas related to nanomedicine. However, a major limitation in the development of CNT-based therapeutic nanomaterials is a lack of reliable and reproducible data describing their chemical and structural composition. Knowledge of properties including purity, structural quality, dispersion state, and concentration are essential before CNTs see widespread use in in vitro and in vivo experiments. In this work, we describe the characterization of several commercially available and two in-house-produced CNT samples and discuss the physicochemical profiles that will support their use in nanomedicine.Methods: Eighteen single-walled and multi-walled CNT raw materials were characterized using established analytical techniques. Solid CNT powders were analyzed for purity and structural quality using thermogravimetric analysis and Raman spectroscopy. Extinction coefficients for each CNT sample were determined by ultraviolet-visible near infrared absorption spectroscopy. Standard curves for each CNT sample were generated in the 0&ndash;5 &micro;g/mL concentration range for dispersions prepared in 1,2-dichlorobenzene.Results: Raman spectroscopy and thermogravimetric analysis results demonstrated that CNT purity and overall quality differed substantially between samples and manufacturer sources, and were not always in agreement with purity levels claimed by suppliers. Absorbance values for individual dispersions were found to have significant variation between individual single-walled CNTs and multi-walled CNTs and sources supplying the same type of CNT. Significant differences (P &lt; 0.01) in extinction coefficients were observed between and within single-walled CNTs (24.9&ndash;53.1 mL&bull;cm-1&bull;mg-1) and multi-walled CNTs (49.0&ndash;68.3 mL&bull;cm-1&bull;mg-1). The results described here suggest a considerable role for impurities and structural inhomogeneities within individual CNT preparations and the resulting spectroscopic properties of their dispersions.Conclusion: Raw CNT materials require thorough analytical workup before they can be used as nanoexcipients. This applies especially to the determination of CNT purity, structure, and concentration. The results presented here clearly demonstrate that extinction coefficients must be determined for individual CNT preparations prior to their use.Keywords: carbon nanotubes, pharmaceutical characterization, Raman spectroscopy, thermogravimetric analysis, ultraviolet-visible near infrared spectroscopy
format	article
author	Ivanova MV Lamprecht C Loureiro MJ Huzil JT Foldvari M
author_facet	Ivanova MV Lamprecht C Loureiro MJ Huzil JT Foldvari M
author_sort	Ivanova MV
title	Pharmaceutical characterization of solid and dispersed carbon nanotubes as nanoexcipients
title_short	Pharmaceutical characterization of solid and dispersed carbon nanotubes as nanoexcipients
title_full	Pharmaceutical characterization of solid and dispersed carbon nanotubes as nanoexcipients
title_fullStr	Pharmaceutical characterization of solid and dispersed carbon nanotubes as nanoexcipients
title_full_unstemmed	Pharmaceutical characterization of solid and dispersed carbon nanotubes as nanoexcipients
title_sort	pharmaceutical characterization of solid and dispersed carbon nanotubes as nanoexcipients
publisher	Dove Medical Press
publishDate	2012
url	https://doaj.org/article/9698c18bd602468981510294b5d67545
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_version_	1718399826912083968

Pharmaceutical characterization of solid and dispersed carbon nanotubes as nanoexcipients

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