Freeze-drying of nanoparticles: How to overcome colloidal instability by formulation and process optimization

Trenkenschuh, Eduard; Frieß, Wolfgang

doi:10.1016/j.ejpb.2021.05.024

Cited by 98 publications

(63 citation statements)

References 230 publications

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“…Second, we will discuss the changes in the molecular state during the freezing of NS-I. It has been reported that a freeze-concentrated phase is formed owing to the crystallization of ice during the freezing process. , The ChO/γ-CD inclusion complex dissolved in water at a very low concentration was concentrated by ice crystallization during the freezing process of NS-I, together with the NS-I particles. This concentration brought the crystallization of the ChO/γ-CD inclusion complex.…”

Section: Resultsmentioning

confidence: 99%

Drug-Loaded Nanocarriers Composed of Cholesteryl Oleate Crystal Cores and Multiple-Nanosheet Shells of γ-Cyclodextrin Inclusion Complex Crystals

Ishimoto

Sasako²,

Omori

et al. 2022

Langmuir

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In this study, we prepared drug-loaded nanocarriers made of cholesteryl oleate (ChO) and γ-cyclodextrin (γ-CD). A nanosuspension (nanosuspension-I, NS-I) containing nanoparticles with a mean size of approximately 170 nm was obtained through the solvent-diffusion method using ethanol. A second nanosuspension (nanosuspension-II, NS-II), which was prepared by freeze-drying and redispersion of NS-I, exhibited an increased particle size of approximately 210 nm. Cryogenic transmission electron microscopy (cryo-TEM) and atomic force microscopy (AFM) force−distance curves indicated that the nanoparticles in NS-I were oblong and soft. However, those in NS-II were angular and stiff, and, interestingly, multiple nanosheets covered the solid−liquid interface. Synchrotron wide-angle X-ray diffraction (WAXD) analysis of NS-II indicated that the nanoparticles in it had a core−shell structure, where the ChO crystal in the inner core was covered by multiple nanosheets of ChO/γ-CD inclusion complex crystals. The X-ray peak analysis suggested that the γ-CD columns of the nanosheets were vertically stacked onto the ChO crystal interface. It was found that the nanosheets on the nanoparticle interface were formed during the freezing process. A model drug carbamazepine (CBZ) was loaded into the ChO/γ-CD nanoparticles by pre-dissolving CBZ in ethanol during the solvent-diffusion process. Cryo-TEM, 1 H NMR, ζ-potentials, and synchrotron WAXD indicated that CBZ was unexpectedly loaded into the shell as a CBZ/γ-CD inclusion complex crystalline nanosheet. The specific nanosheet structure, where ChO and CBZ coexisted in the same crystal of γ-CD, could achieve CBZ loading in the nanoparticles. ChO/γ-CD nanoparticles with the unique core−shell structure are expected to perform as practical carriers for drug delivery.

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Section: Resultsmentioning

confidence: 99%

Drug-Loaded Nanocarriers Composed of Cholesteryl Oleate Crystal Cores and Multiple-Nanosheet Shells of γ-Cyclodextrin Inclusion Complex Crystals

Ishimoto

Sasako²,

Omori

et al. 2022

Langmuir

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“…Most metallic nanoparticles are produced in suspensions and are chemically and physically unstable. Lyophilization as a drying technique represents a way to achieve dry nanoparticles and, with them, long-term stability at room temperature or the possibility of their use for various biomedical applications [ 42 ]. In the present study, dry AuNPs were used, which were synthesized by the USP method [ 43 ] and lyophilization for mixing into the PMMA matrix.…”

Section: Discussionmentioning

confidence: 99%

Unraveling the Antibiofilm Activity of a New Nanogold Resin for Dentures and Epithesis

et al. 2022

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Dentures and epitheses are mostly made from poly(methyl methacrylate) (PMMA), which does not show antimicrobial properties. They present reservoirs of microorganisms grown in biofilms. The aim of this study is to prepare a PMMA enriched with gold nanoparticles (AuNPs)-PMMA/AuNPs and the examination of its physical, mechanical and antimicrobial properties. The AuNPS were synthetized from HAuCl4 using the ultrasonic spray pyrolysis method with lyophilization. The PMMA/AuNP samples were compared to PMMA samples. Density was measured by pycnometer. Microhardness was evaluated using the Vickers hardness test. Monomicrobial biofilm formation (Streptococcus mitis, Candida albicans, Staphylococcus aureus and Escherichia coli) was measured by colony-forming units (CFUs) and MTT test and visualized by SEM. AuNP release was measured indirectly (the CFUs of the medium around the sample). The density and microhardness of the PMMA/AuNPs were similar to those of the PMMA. CFU and MTT values for the biofilms formed on the PMMA for each of the tested species were higher than those of the biofilms formed on the PMMA/AuNPs. The CFUs of the medium around the sample were similar for both materials. PMMA/AuNPs showed a significant reduction in the monomicrobial biofilms of all tested species. AuNPs are not released from PMMA/AuNPs. Density, indirect measurement of residual monomer and dentures weight were similar between PMMA and PMMA/AuNPs. Microhardness, as a measure of the wear resistance, was also similar between tested discs.

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“…Furthermore, nanoparticles that differ in morphological structure, size, charge, and chemical instabilities require different considerations related to formulation, process, and storage. In addition, formulation design of freeze-dried nanoparticles should consider liquid state colloidal stabilization mechanism as nanoparticles are also predisposed to aggregation during freeze drying processes ( Trenkenschuh and Friess, 2021 ).…”

Section: Instability Of Immunoengineering Materialsmentioning

confidence: 99%

Freeze-drying for the preservation of immunoengineering products

Kommineni¹,

Butreddy²,

Jyothi³

et al. 2022

iScience

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Freeze-drying of nanoparticles: How to overcome colloidal instability by formulation and process optimization

Cited by 98 publications

References 230 publications

Drug-Loaded Nanocarriers Composed of Cholesteryl Oleate Crystal Cores and Multiple-Nanosheet Shells of γ-Cyclodextrin Inclusion Complex Crystals

Drug-Loaded Nanocarriers Composed of Cholesteryl Oleate Crystal Cores and Multiple-Nanosheet Shells of γ-Cyclodextrin Inclusion Complex Crystals

Unraveling the Antibiofilm Activity of a New Nanogold Resin for Dentures and Epithesis

Freeze-drying for the preservation of immunoengineering products

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