Detection of Crystalline Ibuprofen Components in Ibuprofen-Loaded SBA-15 Mesoporous Silica Using Time-Domain NMR
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.
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BibTeX
@article{kobayashi2026detection,
title = {{Detection of Crystalline Ibuprofen Components in Ibuprofen-Loaded SBA-15 Mesoporous Silica Using Time-Domain NMR}},
author = {Madoka Kobayashi and Fumitaka Kato and Kotaro Okada},
journal = {Chemical and Pharmaceutical Bulletin},
year = {2026},
month = sep,
doi = {10.1248/cpb.c26-00368},
url = {https://www.jstage.jst.go.jp/article/cpb/74/9/74_c26-00368/_article},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Detection of Crystalline Ibuprofen Components in Ibuprofen-Loaded SBA-15 Mesoporous Silica Using Time-Domain NMR
AU - Madoka Kobayashi
AU - Fumitaka Kato
AU - Kotaro Okada
PY - 2026
DA - 2026/09/10
JO - Chemical and Pharmaceutical Bulletin
DO - 10.1248/cpb.c26-00368
UR - https://www.jstage.jst.go.jp/article/cpb/74/9/74_c26-00368/_article
AB - 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.
SN - 1347-5223
SN - 0009-2363
ER -