# Innovative approach to support therapeutic proteins’ similarity in hydrodynamic size using high-throughput dynamic light scattering and forced degradation

## TL;DR

This paper introduces a new method using high-throughput dynamic light scattering to assess similarity in the size of therapeutic proteins, improving biosimilarity evaluation.

## Contribution

A novel HT-DLS 'sweet spot' method is developed to evaluate hydrodynamic size similarity beyond signature peak analysis.

## Key findings

- Temperature range, increment, and hold time significantly affect analytical similarity in hydrodynamic size.
- Signature peaks alone are insufficient for demonstrating similarity in size distribution.
- Principal component analysis enhances interpretation of HT-DLS data for biosimilarity assessment.

## Abstract

Comparative analytical assessment (CAA) between the reference product and the proposed product forms the basis of the biosimilarity demonstration. Though Dynamic Light Scattering (DLS) has been implemented for CAA, its capability beyond signature peak for similarity assessments has remained unexplored. Herein, we have developed a innovative forced degradation based sweet spot method consisting of signature peak, temperature range, increment and hold time using high throughput-DLS (HT-DLS) to show similarity in hydrodynamic size between products. In our study, we used rituximab, its biosimilars, and insulin analogs as model products to demonstrate product similarity in hydrodynamic size (Dh) size through the HT-DLS sweet spot approach. Our data indicate that temperature range, temperature increment, hold time, and regularization algorithm, all play a role in showing analytical similarity in Dh size. Our data also indicate that establishing DLS signature peaks of the products is insufficient to show analytical similarity in Dh size distribution. Additionally, the temperature range (sweet spot) varies from product to product. Principal component analysis modeling was used for detailed data interpretation. Overall, our HT-DLS based sweet spot method provided informative data to support similarity in Dh size distribution.

The online version contains supplementary material available at 10.1038/s41598-025-97377-6.