Insulin crystals grown in short peptide supramolecular hydrogels show enhanced thermal stability and slower release profile.
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Insulin composite crystalsProtein therapeutics
ACS Appl. Mater. Interfaces https://dx.doi.org/10.1021/acsami.1c00639
SponsorshipThe research leading to these results has received funding from the “la Caixa” Banking Foundation” CaixaImpulse program, EIT-Health PocPlus program and from the Ministry of Economy and Competitiveness of Spain, acknowledged through the following projects: BIO2016-74875-P, BFU2014-57736-P, AGL2014-58883-R, SAF2017-88457-R, AGL2017-85270-R and FIS2017-85954-R co-funded by Fondo Europeo de Desarrollo Regional, ERDF, European Union and FEDER/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades (Spain) projects P18-FR-3533, P12-FQM-2721, P12-FQM-790, CTS235 and CTS164. MA-A and MCM-T, were supported by fellowships from the Ministry of Education. CIBERehd is funded by Instituto de Salud Carlos III.
Protein therapeutics have a major role in medicine, being used to treat diverse pathologies. Their three-dimensional structures offer high specificity and lower toxicity than small organic compounds but also make them less stable limiting their in vivo half-life. Protein-analogs obtained by recombinant DNA technology or by chemical modification and / or the use of drug delivery vehicles have been developed to improve or modulate the in vivo pharmacological activity of proteins. Nevertheless, strategies to improve the shelf-life of protein pharmaceuticals have been less explored which challenge the preservation of their activity. Herein, we present a methodology that simultaneously increases the stability of proteins and modulates the release profile, and implemented with human insulin as a proof of concept. Two novel thermally stable insulin composite crystal formulations intended for the therapeutic treatment of diabetes are reported. These composite crystals have been obtained by crystallizing insulin in agarose and Fmoc-AA (fluorenylmethoxycarbonyl-dialanine) hydrogels. This process affords composite crystals, in which, hydrogel fibers are occluded inside the crystals. Insulin in both crystalline formulations remains unaltered at 50 C for 7 days. Differential Scanning Calorimetry, High Performance Liquid Chromatography, mass spectrometry and in vivo studies have shown that insulin does not degrade after the heat treatment. The nature of the hydrogel modifies the physicochemical properties of the crystals. Crystals grown in Fmoc-AA hydrogel are more stable and have a slower dissolution rate than crystals grown in agarose. This methodology paves the way for the development of more stable protein pharmaceuticals overcoming some of the exiting limitations.