Detection of Crystalline Ibuprofen Components in Ibuprofen-Loaded SBA-15 Mesoporous Silica Using Time-Domain NMR
Year: 2026
Type: article
Abstract: The present study evaluated the applicability of time-domain NMR (TD-NMR) for detecting crystalline ibuprofen components in ibuprofen-loaded mesoporous silica.Ibuprofen-loaded mesoporous silica samples with different drug loadings were prepared, and the physical state of ibuprofen was characterized by nitrogen adsorption, powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), 13 C solid-state NMR spectroscopy, and TD-NMR relaxation measurements.PXRD, DSC, and 13 C solid-state NMR spectroscopy did not clearly detect crystalline ibuprofen in samples with ibuprofen loadings of 10-30%.By contrast, crystalline components were observed in samples with loadings of 40% or higher.These crystalline components were considered to originate predominantly from excess ibuprofen that crystallized outside the mesopores.In the T 1 relaxation analysis using TD-NMR, IBU10-30 was mainly described by a monoexponential function, whereas IBU40-70 required a biexponential function, yielding a long T 1 component associated with crystalline ibuprofen.In the T 2 relaxation analysis, IBU40-70 exhibited an initial rapid decay that was described by a Gaussian function, whereas IBU10-30 showed a gradual exponential decay.The signal proportions of these NMR relaxation components increased with increasing ibuprofen loading and showed trends consistent with the apparent crystallinity estimated by DSC.These results suggest that TD-NMR, particularly T 2 relaxation analysis, may serve as a complementary, nondestructive, and rapid method for evaluating the appearance and increase of crystalline ibuprofen components in mesoporous silica formulations and for monitoring changes in crystallinity.
Authors: Madoka Kobayashi, Fumitaka Kato, Kotaro Okada
Institution: University of Toyama
Language: English
Subfield: Spectroscopy
Field: Chemistry
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7212046702