Extensive research has determined that prolonged sun exposure has significant potential to damage the skin, both with acute and chronic effects due to exposure to UV radiation. Within the spectrum of UV radiation, the UVA component (320-400 nm) represents 95% and can penetrate the epidermis producing indirect DNA damage. UVA rays age skin cells and the exposure is linked to long-term skin damage such as wrinkles, but they are also thought to play an important role in some skin cancers. The UVB component (290-320 nm) that represents the rest of the 5% of the UV radiation is absorbed in the epidermis and directly induces DNA damage and is responsible for burning, tanning, acceleration of skin aging and also plays a key role in the development of skin cancer.
Sunburn Protection Factor (SPF) is a measure of how much solar energy (UV radiation) is required to produce sunburn on protected skin (i.e., in the presence of sunscreen) relative to the amount of solar energy required to produce sunburn on unprotected skin. As the SPF value increases the sunburn protection increases.
In June 2012, the European Standardization Organization (CEN) published the Standard EN ISO 24443:2012 Cosmetics – Sun protection test methods – In vitro determination of sunscreen UVA photo-protection. This is the testing method recommended by COLIPA, currently named Cosmetics Europe. Harmonized with the EN ISO 24443:2012 method, 21 CFR 201.327(j) which provides the specifications for the Broad Spectrum Test, the test that measures a sunscreen drug product’s transmittance/absorbance of ultraviolet (UV) radiation across both the UVB and UVA regions of the spectrum. Both methods have concluded that the in vitro critical wavelength method provides an adequate measure of the UV spectrum protection and in vivo test to demonstrate protection is not required.
EMSL Analytical, Inc. utilizes Perkin Elmer Lambda 950 system for the SPF measurements, one of the highest performing UV/Vis/NIR Systems available. This model provides ultra-high UV/Vis/NIR performance for wavelengths up to 3,300 nm. The 150 mm integrating sphere combination provides an excellent platform for the transmission measurement of SPF values for sunscreen of personal care products for both the research and quality control stages of the manufacturing process, or for label verification claims.