- Antioxidative Power (AP)
(Patent ID: DE102005026133B4)
With this method we analyze the antioxidative activity and reactivity of your products by exposing them to a test radical and evaluate, to which extend it is neutralized by the antioxidants contained in your product. We use test radicals which react with antioxidants,and record their signal intensity decay during the whole reaction. From these intensities a first order kinetic is obtained, and the kinetic parameters are used to calculate the reaction time tr, that is a measure of the reactivity of the particular antioxidant under study, and the characteristic weight wc, which reflects the capacity of the antioxidant. Both parameters are used to calculate the allover Antioxidative Power (AP) of your sample.
For a better handling and the possibility of a direct comparison of the evaluated antioxidant activity and reactivity of different products the AP is standardized to the activity of the established antioxidant substance vitamin C (ascorbic acid). The AP is based on the antioxidant activity of one milliliter of a solution with a concentration of 1 ppm vitamin C. This basic antioxidant activity is defined as an antioxidative unit (AU).
We tested thousands of samples, including raw materials, formulations, food, beverages, actives and molecules, with regard to their Antioxidative Power. How antioxidative is your product?
- Skin Antioxidative Power (SAP)
The SAP describes the ability of the skin to remove free radicals. Skin has its own intrinsic antioxidative protection against oxidative stress due to enzymatic and non-enzymatic antioxidants present in the epidermis and dermis. Antioxidants in cosmetic products can further enhance this antioxidative barrier which can be measured with the SAP method. The reduction of the test radical Tetramethylpiperidinyloxyl (TEMPO) inside the skin biopsy is measured by ESR spectroscopy over time. The SAP values of untreated skin are set to 100% in order to represent the full scope of intrinsic skin protection. The application of antioxidants on the skin enhances the antioxidant activity and therefore enhances the SAP. Higher SAP means lower number of existing free radicals in skin. The test is performed on pig skin or human skin.
- Skin Antioxidative Retention (SAR)
The presence of a sufficient antioxidant active is a basic requirement for the efficient retention of the skin’s antioxidative defense system, representing the first and most important line of defense against the harming effects of the sun. Adding antioxidative ingredients to your product can further contribute to a measurable enhancement of the skin protection. With SAR we determine the protective effect of your cosmetic product on skin. The measurement of the skin‘s own antioxidative power (SAP (verlinkt)) before and after UV irradiation, without and with a topical application of your skin care products containing antioxidants leads to the determination of the so-called Skin Antioxidative Retention (SAR).
- Radical Status Factor (RSF)
(Patent ID: DE102006023364B4)
The RSF method can give insights into the efficacy with which UV filters protect the skin from oxdative stress introduced by the sun. Therefore, the skin is treated with the radical indicator PCA and exposed to UV irradiation. After different time intervals, which correspond to different UV doses, the PCA response is measured and the k-factor (reaction velocity) of the reduction curve is calculated. The number of free radicals generated in the skin is directly proportional to the k-factor. Calibration curves for different density filters and the effects on skin are measured. This is the basis for the determination of the RSF of an unknown sunscreen which is evaluated as a comparison with this calibration curve. On the basis of this observation it is possible to present the relation between the RSF and the number of corresponding free radicals. The normal untreated skin is characterized by a RSF = 1 and the number of measured free radicals corresponds to a concentration of 100%. All products which can be characterized by RSF > 1 are radical protectors, whereas products labelled by RSF < 1 act as radical promoters.
- Radical Potential (RP)
The UV-generated amount of free radicals in cosmetic formulations, raw materials, oils or food products is an important characterization for the stability of the product itself. The more free radicals are generated, even after very low UV radiations (seconds or minutes), the lower is the stability and longevity of the products. Certain ingredients, such as aromas, perfumes, fatty acids, stabilizers, uncoated UV-filters or redox-reactives can influence, mostly negatively, the amount of inducible free radicals in a product, which indicates for example advanced rancidification inside the product. Initial radical generation triggers radical chain reactions, influencing the stability of entire samples and batches. We use an UV-light, a spin probe and an ESR spectrometer and we can characterize the product`s free radical contamination fast and efficiently.
- Radical Hair Protection Factor (RHF)
The RHF method quantifies the amount of free radicals that are generated in the hair in response to UV radiation, and is most helpful to evaluate the protective effect of your hair care product, containing sunscreens, UV filters and radical scavengers. It measures the amount of melanin inside the hair and the increase in melanin paramagnetic activity during UV radiation. Therefore, the intensity of the melanin ESR signal is measured before and after irradiation with different UV doses, and compares treated and untreated hair to conclude on the protective performance of your product.
- Carrier System Stability (CSS)
Carrier systems are often used in cosmetics and dermatology to encapsulate actives which can improve cell penetration abilities and thus the therapeutic effect. They can be categorized by their number of membrane layers, 3-dimensional structures of membranes, vesicles and liposomes. The molecules present, the solvent and other ingredients will define the type of systems that are formed. If these systems are stable in the used matrix can be detected by ESR spectroscopy and so-called spin labels, which we integrate into the membranes of the system, where they can be used to characterize its status, stability and integrity.
- Structural Hair Integrity (HI)
This method measures the structural hair damage of oxidatively stressed hair. The detection of available cysteine groups of the outer keratin layers of the hair, which can be used to quantify the effects of complexing agents, functional silicones and film formers. With HI we can determine the efficacy of repair treatments, conditioners, actives used to restore a hydrophobic character of the hair, and the functionality of the F-layer and protective cystein groups. To do so, we use direct ESR spectroscopy on bleached human hair compared to untreated hair.
Modern life is often affected by pollution. Different air pollutants reach the skin easily, ranging from cigarette smoke to metal ion oxides and dangerous gasses. Together with sun irradiation, free radical generation on pollution-affected skin can be further increased. Anti-pollution cosmetics can help creating a solid and stable film to protect the skin from these effects. How well the skin is protected by an anti-pollution product can be measured with our ESR-based Anti-pollution method, using cigarette smoke and UV-light as external pollutants in a standardized protocol, and the viability and stability of skin-biopsies as a measuring unit.