Spatial characterization of hot melt extruded dispersion systems using thermal atomic force microscopy methods: The effects of processing parameters on phase separation

Moffat, Jonathan G., Qi, Sheng and Craig, Duncan Q. M. (2014) Spatial characterization of hot melt extruded dispersion systems using thermal atomic force microscopy methods: The effects of processing parameters on phase separation. Pharmaceutical Research, 31 (7). pp. 1744-1752. ISSN 0724-8741

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Abstract

Purpose: In this study we explore the use of nano-scale localized thermal analysis (LTA) and transition temperature microcopy (TTM) as a novel combined approach to studying phase separation in HME dispersions of cyclosporine A in Eudragit EPO. Methods: Modulated temperature differential scanning calorimetry (MTDSC), attenuated total reflectance FTIR spectroscopy, nano-LTA and TTM were performed on raw materials and dispersions prepared by hot melt extrusion (HME) and spin coating. For samples prepared by HME, two mixing temperatures (110°C and 150°C) and residence times (5 and 15 min) were investigated. Results: Spin coated samples showed an intermediate T g for the mixed systems consistent with molecular dispersion formation. The HME samples prepared at 110°C showed evidence of inhomogeneity using MTDSC and FTIR, while those produced at 150°C h showed evidence for the formation of a single phase system using MTDSC. The nanothermal methods, however, indicated the presence of phase separated cyclosporine A at the higher preparation temperature while the TTM was able to map regions of differing penetration temperatures, indicating the presence of compositionally inhomogeneous regions in all but the high processing temperature/high residence time samples. Conclusions: TTM is a potentially important new method for studying phase separation and that such separation may remain undetected or poorly understood using conventional bulk analytical techniques.

Item Type:	Article
Faculty \ School:	Faculty of Science > School of Pharmacy (former - to 2024)
UEA Research Groups:	Faculty of Science > Research Groups > Drug Delivery and Pharmaceutical Materials (former - to 2017) Faculty of Science > Research Groups > Pharmaceutical Materials and Soft Matter
Depositing User:	Pure Connector
Date Deposited:	15 Jan 2014 11:40
Last Modified:	06 Feb 2025 04:50
URI:	https://ueaeprints.uea.ac.uk/id/eprint/47260
DOI:	10.1007/s11095-013-1279-x

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