Evaluation of Dispersibility and Stability of Sensitized Latex - Utilizing the qLD Method in the Field of Drugs for In Vitro Diagnostics (Clinical Reagents) -

Introduction

Among the drugs used for in vitro diagnostics (clinical reagents), there are drugs that consist of latex with a protein, such as an antigen or antibody, adsorbed to the surface (sensitized latex). Since tests using sensitized latex can be performed easily and quickly compared to other techniques, it is adopted widely in tests such as those for illnesses and pregnancy. Among the techniques that use sensitized latex, some perform testing by utilizing the agglutination that occurs due to the antigen-antibody reaction between the sensitized latex and the target substance. For such techniques, agglutination with the target substance must be accelerated in order to increase sensitivity. However, self-agglutination and non-specific agglutination with substances other than the target substance need to be suppressed because they can lead to a reduced usable period and incorrect test results. This means that controlling agglutination characteristics is an important issue. Since multiple factors including sensitized latex concentration and solution composition (pH, salt concentration, etc.) affect agglutination characteristics, drug development requires investigation of various conditions and evaluation of the relationship between dispersibility and stability. One system that is effective in increasing efficiency of such investigations on various conditions is the Aggregates Sizer TC, Aggregatetion Analysis System for Biopharmaceuticals (hereafter "Aggregates Sizer TC"), which completes a single quantitative measurement of particle size distribution in a few seconds. Also, accelerated stability testing is possible by agitation testing using a batch cell. This research evaluates the dispersibility and stability of latex sensitized with Protein A or Protein G using the Aggregates Sizer TC. In regard to dispersibility, after causing agglutination by storing Protein A-sensitized latex past its usable period, dispersion treatment was performed on both the stock solution and the diluted solution and the effect of concentration on dispersibility was evaluated. To check stability, the effect of solution composition on stability was evaluated by applying agitation stress to Protein G- sensitized latex in solutions containing different pH levels and salt concentrations to accelerate agglutination. This article introduces the results, which confirm differences in dispersibility and stability for each set of conditions.

April 4, 2018 GMT