Comparison of Low-, Mid-, and High-Frequency Raman Spectroscopy for an In Situ Kinetic Analysis of Lipid Polymorphic Transformations
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
The performance of selected spectral ranges in the low-frequency (10-150 cm-1), mid-frequency (1350-1500 cm-1), and high-frequency (i.e., C-H stretching; 2800-2950 cm-1) domains of Raman spectroscopy was evaluated for the kinetic in situ analysis of lipid polymorphic transformations. Tristearin was used as the primary model lipid and its spray-congealed formulations containing 5% w/w isopropyl myristate (IM), oleic acid (OA), and ethyl oleate (EO) were used due to their ability to differentially modulate the tristearin phase transformation from metastable α-form to the stable β-form. The behavior of bulk samples was interrogated under different isothermal conditions (35, 40, 45 and 50 °C) with Raman microscopy providing complementary particulate-level information for specific conditions, including dispersed state within an aqueous environment. Overall, a clear rank order was observed between the lipid additives (IM > EO > OA) for accelerating the conversion to β-form, best exemplified by the low-frequency Raman (LFR) domain. This spectral range also showed superior characteristics over the more commonly utilized mid-frequency and C-H stretching domains to detect faster onset times for the polymorphic transformations that were attributed to its intrinsic structural sensitivity.
Originalsprog | Engelsk |
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Tidsskrift | Crystal Growth and Design |
Vol/bind | 23 |
Udgave nummer | 11 |
Sider (fra-til) | 7947–7957 |
ISSN | 1528-7483 |
DOI | |
Status | Udgivet - 2023 |
Bibliografisk note
Funding Information:
The authors acknowledge the Novo Nordisk Foundation for supporting this work. B.J.B. and K.B. are supported by a Novo Nordisk Laureate Research Fellowship awarded to Ben Boyd.
Publisher Copyright:
© 2023 American Chemical Society.
ID: 374524777