Evaluation of Methanol-Water and Acetonitrile-Water Binary Mixtures as Eluents for Temperature-dependent Inclusion Chromatography

Zarzycki, Paweł K.; Włodarczyk, Elżbieta; Lou, Dawei; Jinno, Kiyokatsu

doi:10.2116/analsci.22.453

Cited by 22 publications

(10 citation statements)

References 16 publications

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“…To further reduce the amount of proteins loaded on the HPLC column, TCS extracted supernatants were frozen (–40 °C) for a minimum of 6 h to separate the remaining water soluble proteins (frozen bottom layer) from the TCS/acetonitrile rich top layer that remained unfrozen. The freezing point profile of acetonitrile/water mixtures is presented in detail by Zarzycki and others (2006). This phenomenon provides a simple method for sample purification without complex extraction procedures or the risk of compromised analyte recoveries with filtration.…”

Section: Methodsmentioning

confidence: 99%

Association of Triclosan to Casein Proteins Through Solvent‐Mediated High‐Pressure Homogenization

Roach¹,

Dunlap²,

Harte³

2009

Journal of Food Science

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The association of triclosan (TCS), a widely used hydrophobic compound, to the bovine casein micelle is investigated in this study. The use of high-pressure homogenization (HPH) at 0, 100, 200, and 300 MPa was introduced as a method for the dissociation of casein micelles in a skim milk/ethanol solution (1: 1, v/v) in the presence of TCS at 20, 80, and 160 mg/L where ethanol evaporation served as the final step for TCS association to caseins. The majority of TCS (over 80%) was associated with the caseins regardless of initial TCS concentration or applied pressure. TCS association to caseins was enhanced by 30% with continued pressurization to 300 MPa. Micellar dissociation and reassociation was found to be an irreversible process as evidenced by microscopy images. Pressurization to 300 MPa resulted in the formation of an integrated protein network of casein proteins and noncovalently linked whey proteins where the solubility of TCS was enhanced up to 40 times its reported water solubility at the highest initial TCS level of 160 mg/L. Reformed micelles exhibited Newtonian flow behavior at all pressure levels. This study provides evidence for the solubility enhancing quality of TCS through the solvent-mediated pressure/shear-induced dissociation of casein proteins.

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Section: Methodsmentioning

confidence: 99%

Association of Triclosan to Casein Proteins Through Solvent‐Mediated High‐Pressure Homogenization

Roach¹,

Dunlap²,

Harte³

2009

Journal of Food Science

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“…The freezing point of the mobile phase and pressure limitations of the pumping system set the minimum achievable column temperature to near −20 °C for typical aqueous/organic/reversed-phase systems. [40]…”

Section: Introductionmentioning

confidence: 99%

Temperature-assisted on-column solute focusing: A general method to reduce pre-column dispersion in capillary high performance liquid chromatography

Groskreutz

Weber

2014

Journal of Chromatography A

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Solvent-based on-column focusing is a powerful and well known approach for reducingthe impact of pre-column dispersion in liquid chromatography. Here we describe an orthogonal temperature-based approach to focusing called temperature-assisted on-column solute focusing (TASF). TASF is founded on the same principles as the more commonly used solvent-based method wherein transient conditions are created thatlead to high solute retention at the column inlet. Combining the low thermal mass of capillary columns and the temperature dependence of solute retentionTASF is used effectivelyto compress injection bands at the head of the column through the transient reduction in column temperature to 5 °C for a defined 7 mm segment of a 6 cm long 150 μm I.D. column. Following the 30 second focusing time, the column temperature is increased rapidly to the separation temperature of 60 °C releasing the focused band of analytes. We developed a model tosimulate TASF separations based on solute retention enthalpies, focusing temperature, focusing time, and column parameters. This model guides the systematic study of the influence of sample injection volume on column performance.All samples have solvent compositions matching the mobile phase. Over the 45 to 1050 nL injection volume range evaluated, TASF reducesthe peak width for all soluteswith k’ greater than or equal to 2.5, relative to controls. Peak widths resulting from injection volumes up to 1.3 times the column fluid volume with TASF are less than 5% larger than peak widths from a 45 nL injection without TASF (0.07 times the column liquid volume). The TASF approach reduced concentration detection limits by a factor of 12.5 relative to a small volume injection for low concentration samples. TASF is orthogonal to the solvent focusing method. Thus, it canbe used where on-column focusing is required, but where implementation of solvent-based focusing is difficult.

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“…When a binary solvent system of water and acetonitrile is used for TFF, cryo-phase separation of the solvent system must be considered. A mixture of water and acetonitrile phase-separates during the freezing if 35-88 % (v/v) acetonitrile is included in the mixture (Zarzycki et al, 2006). When this cryo-phase separation occurs, a different morphology of powder formulations can be observed (Moon et al, 2019a).…”

Section: Solvent Systemmentioning

confidence: 99%

The Development of Thin-Film Freezing and Its Application to Improve Delivery of Biologics as Dry Powder Aerosols

Hufnagel

Sahakijpijarn

Moon

et al. 2022

KONA

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While the formulation of pharmaceuticals as liquids is common practice, powders are associated with enhanced stability, avoidance of the cold chain, lower dosing requirements, and more convenient administration. These are particularly critical for proteins, as they are expensive and complicated to manufacture. Powders also have improved aerosol properties for pulmonary delivery. Conventional techniques for formulating powders include spray-drying, shelf freeze-drying, spray freeze-drying, and spray freezing into liquid, but they produce powders with poor aerosol performance and/or activity due to suboptimal powder properties. Thin-film freezing (TFF) is a new cryogenic technique that can engineer highly porous, brittle, powder matrices with excellent aerosol performance properties and stability. Herein, we describe TFF in comparison to other cryogenic techniques. Physical properties of TFF powders such as morphology, moisture sorption, stability, solubility, and dissolution, as well as aerosol properties are discussed. In addition, factors that significantly affect the physical and aerosol properties of dry powders prepared by TFF, such as solids content, drug loading, solvent system, excipient, and dry powder delivery device, are analyzed. Finally, we provide evidence supporting the applicability of using TFF to prepare dry powder formulations of protein-based pharmaceuticals, enabling their cold chain-free storage as well as efficient pulmonary delivery.

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Evaluation of Methanol-Water and Acetonitrile-Water Binary Mixtures as Eluents for Temperature-dependent Inclusion Chromatography

Cited by 22 publications

References 16 publications

Association of Triclosan to Casein Proteins Through Solvent‐Mediated High‐Pressure Homogenization

Association of Triclosan to Casein Proteins Through Solvent‐Mediated High‐Pressure Homogenization

Temperature-assisted on-column solute focusing: A general method to reduce pre-column dispersion in capillary high performance liquid chromatography

The Development of Thin-Film Freezing and Its Application to Improve Delivery of Biologics as Dry Powder Aerosols

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