Nanoparticle distribution analysis is a critical process in the research and development (R&D) of colloidal formulations with suspended particulates on the sub-microscale. This can be challenging for formulators given the limitations of established analytical technologies.
Dynamic light scattering (DLS) is one of the leading techniques used to determine accurate particle size distributions (PSDs) for various colloid types with a sensitivity greater than a single nanometre (nm). Consequently, DLS can effectively perform nanoparticle distribution analysis for R&D applications in various markets. However, despite this outstanding sensitivity, most DLS systems remain sensitive to particles of larger dimensions. The presence of contaminants or aggregate structures can subsequently interfere with accurate scattering data, yielding nanoparticle distribution measurement inaccuracies.
This is just one example of the complexities associated with nanoparticle distribution analysis as more markets look to exploit the unique properties of formulations with nanoscale components. In this blog post, Particulate Systems delves into some of the finer details of nanoparticle distribution analysis.
What is a Nanoparticle Formulation?
A formulation is a mixture of chemical compounds characterized by a minimum of one dispersive and one dispersant substance. Though technically heterogeneous, the role of formulators is to create a mixture of dissimilar compounds that is as close to homogenous as possible. This typically involves the use of additive and stabilizing agents to ensure total system stability. A nanoparticle formulation is simply a colloid, or emulsion, comprising a dispersive with a PSD centered around the nanometre range.
Nanoparticle distribution analysis, therefore, is a mathematical estimate of the relative number of nanosized particles present in a formulation.
Nanoparticle Distribution: Importance of Particle Size
Particle size is a critical parameter in all kinds of colloids and formulations. It can underline various KPIs, including:
- The efficacy and method of action (MOA) of certain drug products;
- The flavor profile and mouthfeel of food and beverages;
- The strength of construction materials;
- The applicability of cosmetic products.
QA/QC Nanoparticle Distribution Analysis
Quality assurance (QA) is always a factor in manufacturing spaces and product development, but it is particularly complex in the context of nanoparticle distribution analysis. Process controllers must be concerned with screening incoming raw materials and carefully controlling size reduction (emulsification, homogenization, etc.) and separation processes (i.e. filtering) prior to formulation. In-line analysis may also be required to ensure nanoparticles do not undergo particle size evolutions under processing conditions, which could result in agglomerated structures propagating through to the end-product.
For more information on the stability issues affecting colloidal systems, read our previous blog post Formulation Analysis: 4 Factors Affecting Stability
Formulators today arguably face keener challenges when it comes to quality assurance and control (QA/QC), simply due to the scale of the raw materials that they are forced to control. Fortunately, new systems have built on traditional technologies such as DLS and electrophoretic light scattering (ELS) to provide robust and reliable solutions for nanoparticle distribution analysis in practically any application.
Nanoparticle Distribution Analysis with the Zetasizer DLS Series
Particulate Systems is an industry-leading supplier of high-analytical solutions for both research and product development applications. Our chief solution for nanoparticle distribution analysis is the Zetasizer DLS Series, comprising a choice of established technologies in a single compact unit.
|Model||Which system is right for your lab?||Size||Zeta potential||Molecular weight|
|Zetasizer Ultra||The premium system for the ultimate in colloid and protein characterization||*||*||*|
|Zetasizer Pro||For Expedited Routine Lab measurement- feature Adaptive Correlation||*||*||*|
|Zetasizer Nano ZS||The world’s most widely used DLS instrument||*||*||*|
|Zetasizer Nano ZS90||Entry-level system providing value and versatility||*||*||*|
The high-sensitivity DLS capabilities enable formulators to acquire a true measure of nanoparticle distribution without agitating samples, acquiring rapid light scattering intensity data and mathematically determining size distribution using an appropriate correlation function. This sensitivity is compounded by additional non-invasive back-scatter (NIBS) technology, which measures a much larger number of particles and eliminates outliers to provide the most stable signal possible.
If you would like more information about how DLS is used to measure the distribution of nano-sized particles in colloidal systems, you might like our recent article Nanoparticle Distribution Analysis: DLS or ELS?Posted on