Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
Int J Cosmet Sci. 2022 Jun;44(3):271-288. doi: 10.1111/ics.12773. Epub 2022 May 4.
Drawing parallels from rheotribology can be used to develop a robust instrumental protocol for non-subjective characterization, product development and design of topical dosage forms with desired sensory attributes. However, instrumental characterization of cosmetic products can be influenced by the measurement protocol, thixotropy, flow anomalies like shear banding or wall slip and nature of the film formed on the skin surface. In this study, we evaluated the influence of above parameters on the instrumental sensory evaluation of 12 topical formulations of different galenic forms.
Oscillatory strain sweep measurements (SAOS and LAOS) were performed to investigate the influence of frequency and wall slip on the material parameters. The textural attributes at different consumer touchpoints were evaluated by accounting time-dependent simulation of viscoelastic flow. Further, the influence of film thickness and sample drying on the tactile properties of the topical formulations were studied on a non-biological skin model using a sliding probe tribometer.
The study shows that the flow properties of the semi-solid formulations depend on the timescale of the problem. A few formulations exhibited wall slip to varying degrees in the linear viscoelastic regime where the behaviour was found not to be characteristic of a particular topical dosage form. The material functions obtained from the Lissajous plots suggest that the non-linear flow behaviour of different galenic forms is least influenced by the boundary conditions imposed by the measurement geometry. The results were statistically analysed using principal component analysis where the attributes used for discriminating skin creams during pick up and rub out are found to be closely associated with non-linear rheology. The friction coefficient exhibited speed dependence where it formed different parametric group with rheological data depending on the lubrication regime.
The study highlights that correlations are possible amongst rheological, tribological and instrumental textural analysis data, which can act an impetus for the development of models to predict attributes that drive perception at different consumer touchpoints. However, the choice of instrumental settings, anomalies associated with rheological measurements and friction dependence on a number of parameters can influence the model prediction.
借鉴流变摩擦学可以为具有理想感官属性的局部剂型的非主观特征描述、产品开发和设计开发稳健的仪器化方案。然而，化妆品的仪器化特征可能会受到测量方案、触变性、剪切带或壁滑等流动异常以及在皮肤表面形成的膜的性质的影响。在这项研究中，我们评估了上述参数对 12 种不同赋形剂局部制剂的仪器化感官评估的影响。
进行振荡应变扫描测量（SAOS 和 LAOS）以研究频率和壁滑对材料参数的影响。通过粘弹性流动的时变模拟来评估不同消费者接触点的质地属性。此外，使用滑动探针摩擦仪在非生物皮肤模型上研究了薄膜厚度和样品干燥对局部制剂触感特性的影响。
该研究表明，半固态制剂的流动性能取决于问题的时间尺度。一些制剂在线性粘弹性范围内表现出不同程度的壁滑，其行为不具有特定局部制剂的特征。从 Lissajous 图获得的材料函数表明，不同赋形剂的非线性流动行为受测量几何形状施加的边界条件的影响最小。使用主成分分析对结果进行了统计分析，在提取和涂抹过程中用于区分乳膏的属性与非线性流变学密切相关。摩擦系数表现出速度依赖性，它根据润滑状态与流变数据形成不同的参数组。
该研究强调了流变学、摩擦学和仪器质地分析数据之间存在相关性，这可以为开发模型提供动力，以预测在不同消费者接触点驱动感知的属性。然而，仪器设置的选择、流变测量相关的异常以及摩擦对多个参数的依赖性可能会影响模型预测。
