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Dispersibility - Redispersion

TURBISCAN: A SINGLE TECHNOLOGY FOR COMPLETE DISPERSION ANALYSIS

Pioneer in the direct stability measurement for concentrated media and accelerated aging tests, the Turbiscan technology is the first ready-to-use technology for direct dispersibility and redispersion studies. 

Dispersibility corresponds to the ease to disperse a powder into a liquid, to reach spatial uniformity and the desired particle size. Dispersibility and stability are highly interconnected and a “good” dispersibility is essential to reach the desired shelf life. There are several strategies to optimize the dispersibility: adjusting the formulation (solvent type, choice of dispersant, dispersant concentration…) or the mixing process (mixing time, speed, type of the tool…).

Resuspending properties correspond to the ease of re-disperse powder after a given settling time. It gives the scientist the information if a suspension can be re-homogenized and what time/energy is needed. Being able to refresh a formulation and retrieve its original configuration after several months of storage is essential for some applications like paints, inks, vaccines, beverages… and the resuspending ability is essential to retrieve the correct color, immune answer, or taste.

Key benefits

  • No Sample preparation
  • 200x faster than conventional tests
  • Quantification of dispersibility

Multiple light scattering technology

The SMLS (Static Multiple Light Scattering) provides information about particle size and concentration variation, directly in the native sample, without any dilution (up to 95% v/v).  The SMLS technique consists of sending photons (NIR light source, 880nm) into the sample. These photons are scattered many times by the particles (or droplets) in the dispersion and are detected by 2 synchronous detectors. In the SMLS technique, the Backscattering (BS) signal is measured at 135° for opaque samples and the Transmission (T) signal at 0° from the light source for transparent samples.

The measurement of the BS and T uses specific geometry and optical pathways for extreme sensitivity to the change in particle size and concentration. The light scattering signal is acquired in two different ways: 

  • Scan mode: The acquisition of the BS and T is measured along with the entire sample height at high resolution (down to 20µm) and provides a spatial resolution of the light scattering among the tube height. By repeated scanning, the Turbiscan enables fast detection and quantification of any destabilization process (aggregation, coalescence, sedimentation, phase separation).
     
  • Fast mode: On the other hand, if the reading head is set at a fixed position, the measurement of the T and BS, and so the particle size, can be done at a high frequency (up to 10 measurements per second,) which is ideal to follow fast change in the particle size while processing the dispersion.

 

SMLS associated with the scan mode: Fast (up to 200x faster than visual observation) detection and quantification of the stability on the native sample (no dilution, no additional forces) for shelf-life studies.

SMLS associated with the Fast mode: Online and non-dilution determination of the particle size while procession via the Mixing module (T-MIX) and the circulation module (T-LOOP) for dispersibility and resuspending studies. 

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Data and key features

  • Dispersibility testing by turbiscan
  • Turbiscan Tower by Formulaction
  • Particle Size analysis and dispersibility testing
  • Particle Size analysis

> Dispersibility

Dispersibility is one of the major parameters of dispersed particles and objects and its optimization can help formulators fine-tune the formulation, search for alternative solvents and additives and adjust process parameters.

As stated in the ISO TS22107, dispersibility can be assessed via particle size determination during the dispersion process in a native state (no sample preparation, no dilution…). The association of the SMLS technology and online capabilities of the Turbiscan DNS meet the recommendation of the ISO TS22107 for the formulator to study this essential parameter.

> Online Particle size determination

Working on native sample and without any preparation or product transfer is essential to detect the presence of agglomerate and aggregates especially for nano particle (ISO TS 21357). The SMLS allow mean particle size determination on a wide range of concentration, from 10-4 up to 95%, and from 10nm to 1mm. The SMLS technology is perfectly suitable for online studies of the particle size via the mixing and circulating function of the Turbiscan DNS

  • Dispersibility Ratio
  • Dispersibility Ratio Dispersibility Ratio
  • Dispersibility Ratio

> SMLS at Flow

Online characterization can be done in two different ways via the mixing function (T-MIX) and the circulating function (T-LOOP).

The T-LOOP function allows to study any kind of process by creating a circulation loop from a given process to the measurement chamber of the Turbiscan via a peristaltic pump and specific vial cap. The T-LOOP function gives access to the size reduction kinetic of processes like milling, grinding, emulsification… 

The T-MIX function changes the measurement vial into a mini reactor (10-20mL. Once equipped with the dedicated blade and using the embedded stirrer of the Turbiscan DNS, the liquid inside the Turbiscan can be mixed and the dispersion can be characterized as a function of time or by changing the formulation via the inlet connector (LUER lock) on the cap.

  • Chemical Laboratory
  • Turbiscan LAB Samples - Clarified layer
  • Formulaction Turbiscan LAB samples

> Easy redispersion studies with Turbiscan DNS

In many industrial applications: coatings and paints, injectables drugs, dairy drinks, destabilization is unavoidable and redispersion will be required. The main concern is that the redispersion technique (stirring, shaking, etc.) will not be energetic enough to render the suspension back to its initial, homogeneous state. When this is the case the sample is then unusable and must be discarded. The prediction of this effect and its quantification is critical and a fast, quantitative method is required to answer commonly asked questions: can the suspension be refreshed?

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