Multiscale structure analysis of a pH-responsive gelatin/hydroxypropyl methylcellulose phthalate blend using small-angle scattering

Kämäräinen T, Nogami S, Arima-Osonoi H, Iwase H, Uchiyama H, Tozuka Y, Kadota K (2024)

Publication Type: Journal article

Publication year: 2024

Journal

Journal of Colloid and Interface Science Elsevier

Book Volume: 669

Pages Range: 975-983

DOI: 10.1016/j.jcis.2024.05.038

Abstract

Hypothesis

Hydroxypropyl methylcellulose phthalate (HPMCP) is an enteric polymer that has been employed in drug delivery systems to delay the release of the encapsulated active pharmaceutical ingredients through its pH-responsive solubility change. This has been recently demonstrated as an effective means for delaying the drug release from gelatin/HPMCP hydrogels at gastric pH values. However, structural characteristics of HPMCP agglomeration in gelatin/HPMCP hydrogels is not well understood thus limiting further tailoring of their material properties.


Experiments

We investigated the multiscale structure of a gelatin/HPMCP hydrogel (1:1 by weight) between pH 2 and 6 at 37 °C, i.e. above the upper critical solution transition temperature of gelatin, using small-angle X-ray scattering and contrast-variation small-angle neutron scattering to understand the pH-responsive structure of HPMCP and the cross-correlation between gelatin and HPMCP.


Findings

Agglomeration of HPMCP between pH 2 and 4 was evidenced by the formation of mass fractal structures, with a fractal dimension ranging from 1.5 to 2.7, comprising primary particles with a radius of gyration ranging from 70 to 140 Å. Blending with gelatin influenced the fractal structure of HPMCP and the primary particle size. Gelatin and HPMCP exhibited negative cross-correlation in all probed length scales and pH values, which was attributed to volume-exclusion interaction in a double-network-like solution architecture.

Involved external institutions

Comprehensive Research Organization for Science and Society JP Japan (JP) Osaka Medical and Pharmaceutical University JP Japan (JP)

How to cite

APA:

Kämäräinen, T., Nogami, S., Arima-Osonoi, H., Iwase, H., Uchiyama, H., Tozuka, Y., & Kadota, K. (2024). Multiscale structure analysis of a pH-responsive gelatin/hydroxypropyl methylcellulose phthalate blend using small-angle scattering. Journal of Colloid and Interface Science, 669, 975-983. https://doi.org/10.1016/j.jcis.2024.05.038

MLA:

Kämäräinen, Tero, et al. "Multiscale structure analysis of a pH-responsive gelatin/hydroxypropyl methylcellulose phthalate blend using small-angle scattering." Journal of Colloid and Interface Science 669 (2024): 975-983.

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