Assessing biological activity of makeup actives

Until recently, colour cosmetics (including foundations, lip sticks, mascara and similar decorative formulas) were not designed for inclusion of active ingredients which would, in addition to the immediate masking and decorative effect, achieve biological results in the long run. This situation is changing and the objective of this article is to explore the possibility of combining decorative cosmetic formulations with biologically active ingredients in order to achieve visible short-term effects and beneficial long-term physiological changes. Among the difficulties encountered, one may note formulation and efficacy measurement (claim substantiation) as instrumental methods from skin care are not always well adapted. Three examples are chosen: active volumising lipbalm, eyelash lengthening mascara and active anti-wrinkle foundation.

Active volumising lipbalm

For women, a well-delineated mouth with full, pouting lips is a major attractive feature. Therefore, it seems obvious to allow women to benefit from a sophisticated and effective cosmetic procedure while decorating their lips. For inclusion in decorative lip treatment balms and sticks, a plant complex associated with a matrikin-mimetic peptide (commercially named VolulipTM, patent WO 2010/082175) was designed to stimulate collagen I, III, IV, and fibronectin synthesis in normal human fibroblasts. Collagens I and IV, however, produced by dermal cells and deposited in the extracellular space, need to undergo a maturation phase in order to ensure the elasticity of the skin, and to bind the dermis to the epidermis. One of the components necessary for the maturation of certain collagens is the chaperone protein HSP47 (heat-shock protein). Specific to collagen-producing cells, HSP47 binds to collagens I through V. This function enables the collagen to be reinforced and protected, particularly against proteases, before it exits the cell. The absence of HSP47 in mice yields animals whose skin is fragile; Figure 1 shows the increase in HSP47 synthesis in presence of increased concentrations of the matrikin-mimetic peptide. The quantity of HSP47 was evaluated after deposition and running on an appropriate membrane followed by immunolabelling and detection by chemiluminescence. Band intensity was quantified using dedicated software. Furthermore, increased synthesis of ECM molecules was observed on human dermal fibroblasts when incubated with the matrikin-mimetic peptide: collagen I: +133%, collagen III: +223%, fibronectin: +73%; EDJ related collagen IV: +84% and laminin 5: +62%; moisture promoting hyaluronic acid: +101% and aquaporin 3: +31%, all this at the level of 1%, which is easily incorporated into lip treatment products (balm, stick, gloss). The methods used to make these measurements are immunofluorescent labelling (collagen I and III), Elisa (fibronectin, collagen IV, laminin 5, HA), protein labelling on frozen sections (aquaporin 3). A clinical trial with a lip balm containing 1% of the matrikinmimetic peptide was conducted by combining several complementary methods: Evaluation of the firmness of the lip by Aeroflexmeter, evaluation of restored dermal density by labial ultrasound, evaluation of moisturisation by Moisturemeter-D, evaluation of lip volume, curvature and softness by fringe projection (FOITS). Whereas the placebo balm showed no measurable effects, the active lip balm increased lip moisture (+50.6% for all the epidermis 20 h after the last application), tissue firmness and density (+13.3% and +8.5% respectively), measurably improved softness (+10.5%) and shape (volume: +15.1%) after one month (p<0.01 to p<0.05). One needs to mention the first measurement of lip tissue firmness, for which a novel instrumental technique (Aeroflexmeter) was used: a non-contact pressurized air nozzle coupled to a laser detection device.1 To quantify dermal tissue density, an ultrasound miniprobe designed for studying gum disease was used for the first time on lips. The size of the probe (1 cm2) enables investigation of areas that are difficult to access or of limited area. Sederma’s specific and original development focused on the use of the probe for the lips. The difficulty in formulating ‘active’ lip treatment products thus lies mostly in the technique of claim substantiation, given the special nature of lip tissue.