Nephelometry / Turbidity
Method Introduction
Nephelometry/turbidity is a quick and noninvasive technique for detecting relative changes in aggregate and particle content in a liquid sample.
A laser light passes through the sample, and either the scattered light is detected, e.g., at an angle of 90° to the laser source (= nephelometry,) or the transmitted light is detected at an angle of 180° to the laser source (= turbidity). Typically, a 320–800 nm laser wavelength is absorbed by formulation components, such as proteins, peptides, DNA/RNA, formulation excipients (e.g., amino acids), and water. In both cases, samples’ clarity and degree of opalescence are measured according to a setup described in current pharmacopeias (Ph. Eur. 2.2.1 and USP <855>) and assigned based on comparative measurements against reference formazin suspensions.
Applications
Nephelometry/turbidity measurements are nonspecific but highly useful for comparing samples relative to one another, e.g., for rapid screening of protein aggregation during formulation development.
The technique requires limited sample preparation and is non-destructive. Although nephelometry/turbidimetry does not provide information about the size, concentration, or nature of protein aggregates or particles, the technique is often used to detect relative changes in the aggregation status. Because of its high sensitivity, nephelometry/turbidity can detect the formation of particles in liquid samples very early during forced-degradation or stability studies. It should be noted, however, that turbidity can also originate from other factors, such as high protein concentration, and does not necessarily reflect the presence of aggregates or particles.
Quality and Biosafety Level
We provide all our analytical services with the highest quality standards. Experienced scientists carry out each project, and a scientific reviewer comprehensively checks every report or data presentation.
We offer this technology with the following quality and biosafety levels:
R&D level
We offer this method under R&D. Our GRP system assures the highest-quality research standards.
Up to biosafety level 2
This method can be applied to nucleic acids, viruses, cells, viral vectors, including lentiviruses and more.
Analytical Method Development, Qualification and Validation
For common sample types, we can often apply standardized methods with little setup effort. However, when needed, our experienced analytical experts create or optimize custom methods tailored to your active pharmaceutical ingredient, product type and development phase.
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