Magnesium stearate surface coverage on tablets and drug crystals: Insights from SEM-EDS elemental mapping

Chamara A. Gunawardana; Angela Kong; Daniel O. Blackwood; C. Travis Powell; Joseph F. Krzyzaniak; Myles C. Thomas; Changquan Calvin Sun

doi:10.1016/j.ijpharm.2022.122422

Magnesium stearate surface coverage on tablets and drug crystals: Insights from SEM-EDS elemental mapping

Chamara A. Gunawardana, Angela Kong, Daniel O. Blackwood, C. Travis Powell, Joseph F. Krzyzaniak, Myles C. Thomas, Changquan Calvin Sun

Research output: Contribution to journal › Article › peer-review

11 Scopus citations

Abstract

Scanning electron microscopy-based energy dispersive X-ray spectroscopy (SEM-EDS) is proposed as a versatile tool for quantifying surface area coverage (SAC) by magnesium stearate (MgSt) on pharmaceutical tablets and particles. Our approach involved fast elemental mapping and subsequent SAC quantitation by image analysis. The study was conducted using a multi-component system, but the particle-level mapping was limited to active pharmaceutical ingredient (API) crystals. For both tablets and API particles, the calculated SAC against MgSt loading afforded a positive linear correlation over the range of MgSt levels examined in this work. On the tablet surface, MgSt was found to be preferentially concentrated at or in the close vicinity of grain boundaries, supporting the idea of compression-driven migration and relocation of MgSt within the tablet. On the particle surface, only discrete aggregates of MgSt were observed, as opposed to the widely accepted phenomenon of the formation of a thin lubricant film around host particles. The selection of proper SEM-EDS operating conditions and the challenges confronted in particle surface mapping are discussed in detail.

Original language	English (US)
Article number	122422
Pages (from-to)	122422
Journal	International journal of pharmaceutics
Volume	630
DOIs	https://doi.org/10.1016/j.ijpharm.2022.122422 https://doi.org/10.1016/j.ijpharm.2022.122422
State	Published - Jan 5 2023

Bibliographical note

Funding Information:
This work was supported by a grant from Pfizer Inc. Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from the NSF through the MRSEC (Award Number DMR-2011401) and the NNCI (Award Number ECCS-2025124) programs.

Publisher Copyright:
© 2022 Elsevier B.V.

Keywords

Chemical imaging
Elemental mapping
Magnesium stearate
energy dispersive X-ray spectroscopy (EDS)
scanning electron microscopy (SEM)
surface area coverage (SAC)

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Gunawardana, C. A., Kong, A., Blackwood, D. O., Travis Powell, C., Krzyzaniak, J. F., Thomas, M. C., & Calvin Sun, C. (2023). Magnesium stearate surface coverage on tablets and drug crystals: Insights from SEM-EDS elemental mapping. International journal of pharmaceutics, 630, 122422. Article 122422. https://doi.org/10.1016/j.ijpharm.2022.122422, https://doi.org/10.1016/j.ijpharm.2022.122422

Gunawardana, CA, Kong, A, Blackwood, DO, Travis Powell, C, Krzyzaniak, JF, Thomas, MC & Calvin Sun, C 2023, 'Magnesium stearate surface coverage on tablets and drug crystals: Insights from SEM-EDS elemental mapping', International journal of pharmaceutics, vol. 630, 122422, pp. 122422. https://doi.org/10.1016/j.ijpharm.2022.122422, https://doi.org/10.1016/j.ijpharm.2022.122422

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abstract = "Scanning electron microscopy-based energy dispersive X-ray spectroscopy (SEM-EDS) is proposed as a versatile tool for quantifying surface area coverage (SAC) by magnesium stearate (MgSt) on pharmaceutical tablets and particles. Our approach involved fast elemental mapping and subsequent SAC quantitation by image analysis. The study was conducted using a multi-component system, but the particle-level mapping was limited to active pharmaceutical ingredient (API) crystals. For both tablets and API particles, the calculated SAC against MgSt loading afforded a positive linear correlation over the range of MgSt levels examined in this work. On the tablet surface, MgSt was found to be preferentially concentrated at or in the close vicinity of grain boundaries, supporting the idea of compression-driven migration and relocation of MgSt within the tablet. On the particle surface, only discrete aggregates of MgSt were observed, as opposed to the widely accepted phenomenon of the formation of a thin lubricant film around host particles. The selection of proper SEM-EDS operating conditions and the challenges confronted in particle surface mapping are discussed in detail.",

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note = "Funding Information: This work was supported by a grant from Pfizer Inc. Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from the NSF through the MRSEC (Award Number DMR-2011401) and the NNCI (Award Number ECCS-2025124) programs. Publisher Copyright: {\textcopyright} 2022 Elsevier B.V.",

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N2 - Scanning electron microscopy-based energy dispersive X-ray spectroscopy (SEM-EDS) is proposed as a versatile tool for quantifying surface area coverage (SAC) by magnesium stearate (MgSt) on pharmaceutical tablets and particles. Our approach involved fast elemental mapping and subsequent SAC quantitation by image analysis. The study was conducted using a multi-component system, but the particle-level mapping was limited to active pharmaceutical ingredient (API) crystals. For both tablets and API particles, the calculated SAC against MgSt loading afforded a positive linear correlation over the range of MgSt levels examined in this work. On the tablet surface, MgSt was found to be preferentially concentrated at or in the close vicinity of grain boundaries, supporting the idea of compression-driven migration and relocation of MgSt within the tablet. On the particle surface, only discrete aggregates of MgSt were observed, as opposed to the widely accepted phenomenon of the formation of a thin lubricant film around host particles. The selection of proper SEM-EDS operating conditions and the challenges confronted in particle surface mapping are discussed in detail.

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Magnesium stearate surface coverage on tablets and drug crystals: Insights from SEM-EDS elemental mapping

Abstract

Bibliographical note

Keywords

MRSEC Support

PubMed: MeSH publication types

Publisher link

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University of Minnesota Materials Research Science and Engineering Center (DMR-2011401)

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Magnesium stearate surface coverage on tablets and drug crystals: Insights from SEM-EDS elemental mapping

Abstract

Bibliographical note

Keywords

MRSEC Support

PubMed: MeSH publication types

Publisher link

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Other files and links

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University of Minnesota Materials Research Science and Engineering Center (DMR-2011401)

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