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 ORCID: https://orcid.org/0000-0003-1872-9572 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
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:	27 Oct 2023 01:14
URI:	https://ueaeprints.uea.ac.uk/id/eprint/47260
DOI:	10.1007/s11095-013-1279-x

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