# Methodological Study on Determination of Recombinant Adeno-Associated Virus Particle Titer Through Size Exclusion Chromatography with Multiangle Light Scattering and Collaborative Calibration of Standard Substances

## TL;DR

This paper introduces a new method to accurately measure the number of virus particles in gene therapy products using advanced chromatography and light scattering techniques.

## Contribution

The study proposes a validated SEC-UV-MALS-RI method for precise and durable rAAV particle titer determination.

## Key findings

- The SEC-UV-MALS-RI method showed good specificity, linearity, precision, accuracy, and durability.
- Collaborative calibration using standard substances enabled rapid and accurate viral titer measurements in rAAV products.

## Abstract

Adeno-associated virus (AAV) is a promising gene therapy vector due to its high transduction efficiency, low pathogenicity, low immunogenicity, and the ability to mediate the long-term stable expression of exogenous genes. The viral particle titer is an essential quality attribute of recombinant adeno-associated virus (rAAV) gene therapy products. Multiangle light scattering (MALS) is an important means of directly measuring the absolute molecular weight and distribution of macromolecular drugs. This study established and validated a method based on SEC-UV-MALS-RI tandem technology for accurately determining rAAV particle titers. The verification results indicated that the method exhibited good specificity, linearity, precision, accuracy, and durability. Several collaborative laboratories used this method to calibrate the standard substances needed for rAAV particle titer determination. The results suggested that combining the SEC-MALS method with standard substances enables the rapid and accurate measurement of the viral particle titers in rAAV gene therapy products.