Mechanistic Investigation into Crystallization of Hydrated Co-Amorphous Systems of Flurbiprofen and Lidocaine

<b>Background:</b> It is generally accepted that water as a plasticizer can decrease the glass transition temperatures (T<sub>g</sub>s) of amorphous drugs and drug delivery systems, resulting in physical instabilities. However, a recent study has reported an anti-plasticizing...

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Main Authors: Xiaoyue Xu, Holger Grohganz, Justyna Knapik-Kowalczuk, Marian Paluch, Thomas Rades
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Pharmaceutics
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Online Access:https://www.mdpi.com/1999-4923/17/2/175
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author Xiaoyue Xu
Holger Grohganz
Justyna Knapik-Kowalczuk
Marian Paluch
Thomas Rades
author_facet Xiaoyue Xu
Holger Grohganz
Justyna Knapik-Kowalczuk
Marian Paluch
Thomas Rades
author_sort Xiaoyue Xu
collection DOAJ
description <b>Background:</b> It is generally accepted that water as a plasticizer can decrease the glass transition temperatures (T<sub>g</sub>s) of amorphous drugs and drug delivery systems, resulting in physical instabilities. However, a recent study has reported an anti-plasticizing effect of water on amorphous lidocaine (LID). In co-amorphous systems, LID might be used as a co-former to impair the plasticizing effect of water. <b>Method:</b> Flurbiprofen (FLB) was used to form a co-amorphous system with a mole fraction of LID of 0.8. The effect of water on the stability of co-amorphous FLB-LID upon hydration was investigated. The crystallization behaviors of anhydrous and hydrated co-amorphous FLB-LID systems were measured by an isothermal modulated differential scanning calorimetric (iMDSC) method. The relaxation times of the co-amorphous FLB-LID system upon hydration were measured by a broadband dielectric spectroscopy (BDS), and the differences in Gibbs free energy (ΔG) and entropy (ΔS) between the amorphous and crystalline phases were determined by differential scanning calorimetry (DSC). <b>Results:</b> It was found that the crystallization tendency of co-amorphous FLB-LID decreased with the addition of water. Molecular mobility and thermodynamic factors were both investigated to explain the difference in crystallization tendencies of co-amorphous FLB-LID upon hydration. <b>Conclusions:</b> The results of the study showed that LID could be used as an effective co-former to decrease the crystallization tendency of co-amorphous FLB-LID upon hydration by enhancing the entropic (ΔS) and thermodynamic activation barriers (TΔS)<sup>3</sup>/ΔG<sup>2</sup>) to crystallization.
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spelling doaj-art-25b0782e7e2448d3ba2b91938e56fbd22025-08-20T02:03:41ZengMDPI AGPharmaceutics1999-49232025-01-0117217510.3390/pharmaceutics17020175Mechanistic Investigation into Crystallization of Hydrated Co-Amorphous Systems of Flurbiprofen and LidocaineXiaoyue Xu0Holger Grohganz1Justyna Knapik-Kowalczuk2Marian Paluch3Thomas Rades4Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, DenmarkDepartment of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, DenmarkSMCEBI, Institute of Physics, Faculty of Science and Technology, University of Silesia in Katowice, 75 Pułku Piechoty 1a, 41-500 Chorzów, PolandSMCEBI, Institute of Physics, Faculty of Science and Technology, University of Silesia in Katowice, 75 Pułku Piechoty 1a, 41-500 Chorzów, PolandDepartment of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark<b>Background:</b> It is generally accepted that water as a plasticizer can decrease the glass transition temperatures (T<sub>g</sub>s) of amorphous drugs and drug delivery systems, resulting in physical instabilities. However, a recent study has reported an anti-plasticizing effect of water on amorphous lidocaine (LID). In co-amorphous systems, LID might be used as a co-former to impair the plasticizing effect of water. <b>Method:</b> Flurbiprofen (FLB) was used to form a co-amorphous system with a mole fraction of LID of 0.8. The effect of water on the stability of co-amorphous FLB-LID upon hydration was investigated. The crystallization behaviors of anhydrous and hydrated co-amorphous FLB-LID systems were measured by an isothermal modulated differential scanning calorimetric (iMDSC) method. The relaxation times of the co-amorphous FLB-LID system upon hydration were measured by a broadband dielectric spectroscopy (BDS), and the differences in Gibbs free energy (ΔG) and entropy (ΔS) between the amorphous and crystalline phases were determined by differential scanning calorimetry (DSC). <b>Results:</b> It was found that the crystallization tendency of co-amorphous FLB-LID decreased with the addition of water. Molecular mobility and thermodynamic factors were both investigated to explain the difference in crystallization tendencies of co-amorphous FLB-LID upon hydration. <b>Conclusions:</b> The results of the study showed that LID could be used as an effective co-former to decrease the crystallization tendency of co-amorphous FLB-LID upon hydration by enhancing the entropic (ΔS) and thermodynamic activation barriers (TΔS)<sup>3</sup>/ΔG<sup>2</sup>) to crystallization.https://www.mdpi.com/1999-4923/17/2/175co-amorphouscrystallizationthermodynamicsanti-plasticizingeffect of waterlidocaine
spellingShingle Xiaoyue Xu
Holger Grohganz
Justyna Knapik-Kowalczuk
Marian Paluch
Thomas Rades
Mechanistic Investigation into Crystallization of Hydrated Co-Amorphous Systems of Flurbiprofen and Lidocaine
Pharmaceutics
co-amorphous
crystallization
thermodynamics
anti-plasticizing
effect of water
lidocaine
title Mechanistic Investigation into Crystallization of Hydrated Co-Amorphous Systems of Flurbiprofen and Lidocaine
title_full Mechanistic Investigation into Crystallization of Hydrated Co-Amorphous Systems of Flurbiprofen and Lidocaine
title_fullStr Mechanistic Investigation into Crystallization of Hydrated Co-Amorphous Systems of Flurbiprofen and Lidocaine
title_full_unstemmed Mechanistic Investigation into Crystallization of Hydrated Co-Amorphous Systems of Flurbiprofen and Lidocaine
title_short Mechanistic Investigation into Crystallization of Hydrated Co-Amorphous Systems of Flurbiprofen and Lidocaine
title_sort mechanistic investigation into crystallization of hydrated co amorphous systems of flurbiprofen and lidocaine
topic co-amorphous
crystallization
thermodynamics
anti-plasticizing
effect of water
lidocaine
url https://www.mdpi.com/1999-4923/17/2/175
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AT justynaknapikkowalczuk mechanisticinvestigationintocrystallizationofhydratedcoamorphoussystemsofflurbiprofenandlidocaine
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