Filipovic M, Lukic M, Djordjevic S, Krstonosic V, Pantelic I, Vuleta G, Savic S
Higher Education School of Professional Health Studies, Cara Dušana 254, Belgrade, 11080, Serbia.
Department of Pharmaceutical Technology and Cosmetology, University of Belgrade-Faculty of Pharmacy, Vojvode Stepe 450, Belgrade, 11000, Serbia.
Int J Cosmet Sci. 2017 Oct;39(5):486-499. doi: 10.1111/ics.12402. Epub 2017 Jun 14.
Consumers' demand for improved products' performance, alongside with the obligation of meeting the safety and efficacy goals, presents a key reason for the reformulation, as well as a challenging task for formulators. Any change of the formulation, whether it is wanted - in order to innovate the product (new actives and raw materials) or necessary - due to, for example legislative changes (restriction of ingredients), ingredients market unavailability, new manufacturing equipment, may have a number of consequences, desired or otherwise. The aim of the study was to evaluate the influence of multiple factors - variations of the composition, manufacturing conditions and their interactions, on emulsion textural and rheological characteristics, applying the general experimental factorial design and, subsequently, to establish the approach that could replace, to some extent, certain expensive and time-consuming tests (e.g. certain sensory analysis), often required, partly or completely, after the reformulation.
An experimental design strategy was utilized to reveal the influence of reformulation factors (addition of new actives, preparation method change) on textural and rheological properties of cosmetic emulsions, especially those linked to certain sensorial attributes, and droplet size.
The general experimental factorial design revealed a significant direct effect of each factor, as well as their interaction effects, on certain characteristics of the system and provided some valuable information necessary for fine-tuning reformulation conditions. Upon addition of STEM-liposomes, consistency, index of viscosity, firmness and cohesiveness were decreased, as along with certain rheology parameters (elastic and viscous modulus), whereas maximal and minimal apparent viscosities and droplet size were increased. The presence of an emollient (squalene) affected all the investigated parameters in a concentration-dependent manner. Modification of the preparation method (using Ultra Turrax instead of a propeller stirrer) produced emulsions with higher firmness and maximal apparent viscosity, but led to a decrease in minimal apparent viscosity, hysteresis loop area, all monitored parameters of oscillatory rheology and droplet size.
The study showed that the established approach which combines a general experimental design and instrumental, rheological and textural measurements could be appropriate, more objective, repeatable and time and money-saving step towards developing cosmetic emulsions with satisfying, improved or unchanged, consumer-acceptable performance during the reformulation.
消费者对产品性能提升的需求，以及满足安全性和有效性目标的义务，是产品重新配方的关键原因，同时也给配方师带来了一项具有挑战性的任务。配方的任何改变，无论是出于创新产品（新活性成分和原材料）的意愿，还是由于例如立法变化（成分限制）、成分市场缺货、新制造设备等必要原因，都可能产生许多预期或非预期的后果。本研究的目的是应用通用实验析因设计，评估多种因素——成分变化、制造条件及其相互作用对乳液质地和流变特性的影响，随后建立一种方法，在一定程度上替代重新配方后部分或完全经常需要的某些昂贵且耗时的测试（如某些感官分析）。
采用实验设计策略来揭示重新配方因素（添加新活性成分、制备方法改变）对化妆品乳液质地和流变特性的影响，特别是那些与某些感官属性和液滴大小相关的特性。
通用实验析因设计揭示了每个因素及其相互作用对系统某些特性的显著直接影响，并提供了一些微调重新配方条件所需的有价值信息。添加STEM脂质体后，稠度、粘度指数、硬度和内聚性降低，同时某些流变学参数（弹性和粘性模量）也降低，而最大和最小表观粘度以及液滴大小增加。润肤剂（角鲨烯）的存在以浓度依赖的方式影响所有研究参数。制备方法的改变（使用超声均质机而不是螺旋桨搅拌器）产生的乳液具有更高的硬度和最大表观粘度，但导致最小表观粘度、滞后回线面积、所有监测的振荡流变学参数和液滴大小降低。
该研究表明，所建立的结合通用实验设计以及仪器、流变学和质地测量的方法，对于在重新配方过程中开发具有令人满意、改进或不变的、消费者可接受性能的化妆品乳液而言，可能是一种合适、更客观、可重复且节省时间和金钱的步骤。
