Evaluation of two and three fluid nozzle spray drying to prepare co-crystals of salicylic acid and caffeine with improved physicochemical propertiess

Hibbard, T., Shankland, K. ORCID: https://orcid.org/0000-0001-6566-0155 and Al-Obaidi, H. ORCID: https://orcid.org/0000-0001-9735-0303 (2023) Evaluation of two and three fluid nozzle spray drying to prepare co-crystals of salicylic acid and caffeine with improved physicochemical propertiess. Journal of Drug Delivery Science and Technology, 89. 105073. ISSN 1773-2247 doi: 10.1016/j.jddst.2023.105073

Abstract/Summary

Formation of co-crystals using spray drying remains a challenging task due to the rapid nature of the process and the possible impact of solvents on the formation of the co-crystals. The purpose of this work was to generate co- crystals via two-fluid and three-fluid nozzle spray drying using the model system of salicylic acid and caffeine (SAL-CAF). The prepared co-crystal showed a strong tendency to form through spray drying, from a variety of feedstock compositions and through both two-fluid and three-fluid drying methods. Powder X-ray diffraction, Fourier - Transform infrared spectroscopy and differential scanning calorimetry were used to characterise the spray dried powders through comparison to the reported crystal structure and SAL-CAF formed through milling. All spray dried powders showed good agreement to the reported crystal structure but with an additional phase present, determined as the β-polymorph of caffeine. This additional phase was present at different proportions corresponding to the solvent, feedstock concentration and method used. For the three-fluid nozzle method, the feedstock composition was shown to have a large influence on the proportion of co-crystal in the final sample and all three-fluid nozzle samples showed reduced crystallinity compared to the two-fluid nozzle method. The spray dried co-crystals showed resistance to stress conditions over a period of four months and remained detectable following a tableting process. Spray drying is a suitable technique for the preparation of the SAL-CAF co-crystal and with further optimisation of process parameters may be equivalent or superior to milling.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/113737
Identification Number/DOI	10.1016/j.jddst.2023.105073
Refereed	No
Divisions	Interdisciplinary centres and themes > Chemical Analysis Facility (CAF) > Thermal Analysis (CAF) Interdisciplinary centres and themes > Chemical Analysis Facility (CAF) > Xray (CAF)
Publisher	Elsevier
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