Reble Carina, Bayer Michael, Colson Bertrand, Emmler Tanja, Hubaud Jean-Claude, Seise Matthias, Perroux-David Eva, Wiora Georg, Zamudio Diaz Daniela F, Meinke Martina C, Bielfeldt Stephan
Courage + Khazaka electronic GmbH, Cologne, Germany.
Charité - Universitätsmedizin Berlin, Department of Dermatology, Venerology and Allergology, Berlin, Germany.
Int J Cosmet Sci. 2025 Sep;47 Suppl 1:96-114. doi: 10.1111/ics.70007.
The consortium ALT-SPF performed an international round robin test to characterize non-invasive methods as alternatives to the erythema-based testing of sun protection factor (SPF) according to ISO 24444:2019.
Hybrid diffuse reflectance spectroscopy (HDRS) based on a multi-lambda LED light source uses in vivo reflectance spectra on skin to determine sunscreens in vivo absorbance spectra, which are fused with respective in vitro absorbance spectra measured as thin films transmission as described in ISO 24443:2019. As a part of the ALT-SPF consortium initiative, a blinded study on 64 samples was performed in four European laboratories. After further improvements of the method, a blinded re-evaluation based on 16 samples was performed. Five statistical acceptance criteria for new methods were assessed by an independent statistical institute to compare the obtained results to the reference methods for SPF and UVA-PF.
The initial ALT-SPF study 1 showed that the bias criterion was acceptable, while the reproducibility and interlaboratory variability needed further improvement. The re-evaluation study 2 showed that the reproducibility and interlaboratory variability could be considerably improved. Using only n = 10 volunteers and a bias correction based on the initial ALT-SPF study 1 data, the SPF results of the re-evaluation study 2 were close to the acceptance criteria of the ALT-SPF study with criterion 1 (reproducibility) and only 11% over the limit defined by the performance of the gold standard. The UVA-PF results were within the acceptance limits for the acceptance criteria, except criterion 3 being in the 'almost met' range. The re-evaluation study indicates that the method has a comparable precision to the gold standard methods ISO 24444 and ISO 24443.
This study showed that the LED-HDRS method is capable of providing reasonable non-invasive SPF and UVA-PF results and that the performance shows close alignment to the reference method. Thus, it can be proposed as an alternative method to the current standards ISO 24444 and ISO 24443.
ALT-SPF联盟开展了一项国际循环试验，旨在根据ISO 24444:2019对非侵入性方法进行表征，以替代基于红斑的防晒系数（SPF）测试。
基于多波长LED光源的混合漫反射光谱法（HDRS）利用皮肤的体内反射光谱来测定防晒剂的体内吸收光谱，这些光谱与按照ISO 24443:2019所述作为薄膜透射率测量的相应体外吸收光谱相融合。作为ALT-SPF联盟计划的一部分，在四个欧洲实验室对64个样品进行了一项盲法研究。在对该方法进行进一步改进后，基于16个样品进行了盲法重新评估。一个独立的统计机构评估了新方法的五个统计验收标准，以将获得的结果与SPF和UVA-PF的参考方法进行比较。
最初的ALT-SPF研究1表明偏差标准是可接受的，而重现性和实验室间变异性需要进一步改进。重新评估研究2表明重现性和实验室间变异性可以得到显著改善。仅使用n = 10名志愿者并基于最初的ALT-SPF研究1数据进行偏差校正，重新评估研究2的SPF结果接近ALT-SPF研究的验收标准，符合标准1（重现性），仅比金标准性能定义的限值高出11%。UVA-PF结果在验收标准的接受范围内，除了标准3处于“几乎满足”范围。重新评估研究表明该方法具有与金标准方法ISO 24444和ISO 24443相当的精密度。
本研究表明，LED-HDRS方法能够提供合理的非侵入性SPF和UVA-PF结果，并且性能与参考方法相近。因此，它可以作为现行标准ISO 24444和ISO 24443的替代方法被推荐。
