Lebrun Labs LLC, Anaheim, CA, USA.
Cutan Ocul Toxicol. 2023 Mar;42(1):38-48. doi: 10.1080/15569527.2023.2170067. Epub 2023 Jan 28.
OptiSafe (OS) is a shelf stable, nonanimal test for ocular irritation. A recent database search found that half of the OS false positive (FP) materials were associated with reactive oxygen chemistries but were not eye irritants (based on historical rabbit studies by other groups). We hypothesized that naturally occurring tear antioxidants protect the eye from reactive chemistries and that specific tear chemistries might help explain why some materials are FP for nonanimal tests but are reported as nonirritants in the live animal. To test this hypothesis, a prior study evaluated tear antioxidants and found that the tear antioxidant ascorbic acid, added at human physiological tear levels to the OS test, specifically reduced the measured values for these FPs but did not reduce the true-positive rate. Based on these findings, the OS test method was further optimized. The purpose of the current study was to comprehensively evaluate the performance of the further optimized test method for detection of ocular irritants.
The OS test measures chemically induced damage to macromolecules and relates these measured values to ocular irritancy. To improve the performance of OS, we made updates to the material to be tested physiochemical handling procedures, prediction model, and test method to include tear-level concentrations of ascorbic acid. We then retested the 78 chemicals from the prior OS-coded validation study in triplicate and compared the accuracy of the 'nonirritant versus irritant' prediction for the further optimized method with the prior results.
We report that for the detection of 'nonirritant' versus 'irritant' (GHS NC versus categories 2B/A and 1) test substances, the further optimized OS test with ascorbic acid compared with the original version has a FP rate that is reduced from 40.0 to 22.2%, the false-negative (FN) rate remains at 0.0%, and the accuracy improved from 80.3% to 89.2%.
A comparison to OECD-adopted tests demonstrates that the further optimized OS test, like the original method, has a higher accuracy and lower FN rate for the detection of 'nonirritants' versus 'irritants' (GHS Category NC versus 2B/A and 1) than the other eye irritation tests (BCOP, EpiOcular Eye Irritation Test, ICE, Ocular Irritection, and STE).
OptiSafe（OS）是一种货架稳定的非动物眼刺激性测试。最近的数据库搜索发现，OS 的一半假阳性（FP）材料与活性氧化学有关，但不是眼部刺激性物质（基于其他小组的历史兔子研究）。我们假设天然泪液抗氧化剂可保护眼睛免受活性化学物质的侵害，并且特定的泪液化学物质可能有助于解释为什么有些材料在非动物测试中是 FP，但在活体动物中报告为非刺激性物质。为了验证这一假设，先前的一项研究评估了泪液抗氧化剂，发现 OS 测试中添加的人生理泪液水平的抗氧化剂抗坏血酸可特异性降低这些 FP 的测量值，但不会降低真阳性率。基于这些发现，对 OS 测试方法进行了进一步优化。本研究的目的是全面评估进一步优化的测试方法对眼部刺激性物质检测的性能。
OS 测试测量化学诱导的大分子损伤，并将这些测量值与眼刺激性相关联。为了提高 OS 的性能，我们对要测试的材料进行了更新，包括理化处理程序、预测模型和测试方法，以纳入泪液水平的抗坏血酸浓度。然后，我们对先前 OS 编码验证研究中的 78 种化学物质进行了三次重复测试，并将进一步优化方法的“非刺激性物质与刺激性物质”预测的准确性与先前的结果进行了比较。
我们报告说，对于“非刺激性物质”与“刺激性物质”（GHS NC 与类别 2B/A 和 1）测试物质的检测，与原始版本相比，具有抗坏血酸的进一步优化 OS 测试的 FP 率从 40.0%降低到 22.2%，假阴性（FN）率保持在 0.0%，准确性从 80.3%提高到 89.2%。
与 OECD 采用的测试方法相比，进一步优化的 OS 测试，与原始方法一样，对“非刺激性物质”与“刺激性物质”（GHS 类别 NC 与 2B/A 和 1）的检测具有更高的准确性和更低的 FN 率，优于其他眼部刺激测试（BCOP、EpiOcular Eye Irritation Test、ICE、Ocular Irritection 和 STE）。
