An improved method for toxicological profiling of chemical substances

Toxicity profiling is an integral part of the drug discovery pipeline. The 3Rs principle—Replacement, Reduction, and Refinement, is considered a golden rule in determining the most appropriate approach for toxicity studies. The acute toxicity study with proper estimate of median lethal dose (LD50) is usually an initial procedure for the determination of most suitable test doses for preclinical toxicological and pharmacological profiling. Several methods, which have been devised to determine the LD50, are faced with the challenge of using a large number of animals and time constraints. Despite the inherent advantage of the newer OECD Test Guidelines, the increasing concerns among toxicologists, the regulatory authorities and the general public, on the need to adhere to 3Rs principle, necessitated the need for an improved approach. Such an approach should not only minimize the time and number of animals required, but also take into cognizance animal welfare, and give accurate, comparable, and reproducible results across laboratories. While taking advantage of the inherent merits of the existing methods, here is presented the mathematical basis and evaluation of an improved method for toxicity profiling of test substances and estimation of LD50. The method makes use of the generated Table of values for the selection of appropriate test doses. Our proposed method has capacities to optimize the time and number of animal use, ensure more reliable and reproducible results across laboratories, allow for easy selection of doses for subsequent toxicity profiling, and be adaptable to other biological screening beyond toxicity studies.

毒性表征是药物发现管线中不可或缺的一环。3Rs原则（3Rs principle）——即替代（Replacement）、减少（Reduction）与优化（Refinement），被视为确定毒性研究最优方案的黄金准则。精准估算半数致死量（median lethal dose, LD50）的急性毒性试验，通常是确定临床前毒理学与药理学表征所需最优受试剂量的初始流程。目前已开发出多种LD50测定方法，但这类方法均面临着实验动物使用量庞大、耗时较长的困境。尽管新版OECD试验指南具备固有优势，但毒理学家、监管机构与公众对遵循3Rs原则的关注度与日俱增，这推动了对改进型方法的需求。这类改进型方法不仅应尽可能缩短实验时长、减少动物使用量，还需兼顾动物福利，并能在不同实验室间产出准确、可比且可重复的实验结果。本文在借鉴现有方法固有优势的基础上，提出了一种用于受试物质毒性表征与LD50估算的改进方法，并对其数学原理与应用效果进行了评估。该方法借助已生成的数值表格来筛选合适的受试剂量。我们提出的方法能够优化实验时长与动物使用量，确保不同实验室间的实验结果更可靠、可重复，便于后续毒性表征所需剂量的快速筛选，同时还可拓展应用于毒性研究之外的其他生物学筛选场景。