Dueva-Koganov Olga V, Rocafort Colleen, Orofino Steven, Osterwalder Uli, Brito Juan
Ciba Corporation, Tarrytown, NY, USA.
J Cosmet Sci. 2009 Nov-Dec;60(6):587-98.
The proposed rules of the Food and Drug Administration (FDA) for the UVA in vitro testing procedure were applied to the evaluation of various sunscreen formulations and the following technical challenges were observed: when proposed roughened quartz substrates were used, the required coefficient-of-variation criteria were not met, and the dynamic ranges of the available transmittance analyzers were exceeded for sunscreens with high SPF values. In the proposed rules, the FDA requested comment regarding the suitability of other possible substrates. In this research, two modifications to the FDA's proposed rules were evaluated: (a) the use of an alternative substrate, Vitro Skin N-19 (IMS, Inc.) instead of roughened quartz substrate and (b) an increase in application time from 10 seconds to 30 seconds to ensure a uniform distribution of sunscreen product over the application area of the substrate. These two modifications allowed meeting the required coefficient-of-variation criteria without exceeding the dynamic ranges of the available transmittance analyzers. The modified test conditions were utilized for the evaluation of six commercial sunscreens, which fulfilled criteria of "medium" or "high" categories-based on their UVAI/UV ratios. These findings were in agreement with the statement in the proposed rules that the FDA is aware of the difficulty for current sunscreen formulations to meet the "highest" category and believes that allowing such a category will foster additional research and development in this area. To determine if it was possible to achieve a UVA rating greater than 0.95, two experimental sunscreen prototypes with bisoctrizole (USAN), bemotrizinol (USAN), avobenzone, and octocrylene were tested under the modified test conditions and attained the "highest" category. It should be noted that bisoctrizole and bemotrizinol are being evaluated by the FDA under TEA and are not permitted in the US at this time, but they are approved for use in the rest of the world.
美国食品药品监督管理局（FDA）提出的关于UVA体外测试程序的规则被应用于各种防晒配方的评估，并且观察到了以下技术挑战：当使用提议的粗糙石英基底时，未满足所需的变异系数标准，并且对于高防晒系数（SPF）值的防晒霜，现有透光率分析仪的动态范围被超出。在提议的规则中，FDA要求就其他可能的基底的适用性发表意见。在本研究中，对FDA提议的规则进行了两项修改评估：（a）使用替代基底Vitro Skin N - 19（IMS公司）而非粗糙石英基底，以及（b）将涂抹时间从10秒增加到30秒，以确保防晒产品在基底涂抹区域均匀分布。这两项修改使得能够满足所需的变异系数标准，而不会超出现有透光率分析仪的动态范围。修改后的测试条件被用于评估六种商业防晒霜，这些防晒霜根据其UVAI/UV比值符合“中等”或“高”类别的标准。这些发现与提议规则中的陈述一致，即FDA意识到当前的防晒配方难以达到“最高”类别，并认为允许这样一个类别将促进该领域的更多研发。为了确定是否有可能获得大于0.95的UVA评级，在修改后的测试条件下对两种含有双乙苯三唑（通用名）、 bemotrizinol（通用名）、二苯甲酰甲烷和奥克立林的实验性防晒原型进行了测试，并达到了“最高”类别。应当指出的是，双乙苯三唑和bemotrizinol正在由FDA根据TEA进行评估，目前在美国不允许使用，但它们在世界其他地区被批准使用。
