UVA - Broad Spectrum Testing

In-vitro: For UVA or broad spectrum claims to be made, the product must be tested for its ability to absorb light at wavelengths in the UVA region (between 320nm and 400nm). Various methods can be used to determine performance. We conduct in-vitro testing using specialised spectrophotometers fitted with integrating sphere devices and one of several specialised methods, depending on the type of products and the target country. The test is additional to the SPF testing, and the results are normally used to provide the support for the label claim for broad spectrum protection.

In-vivo: PPD or UVA - JCIA or COLIPA. This test, involving 10 human voluteers, is normally performed to the method described in the Japan Cosmetic Industry Association protocol , using a xenon arc solar simulator which has been calibraited to provied the specified UVA light spectrum.

Theforthcoming ISO method will be based on this procedure.

AS 2604 Broad Spectrum
Method 1. Transmission of an 0.8mg/mL organic solvent solution of the sample in a 10 mm
thick cell is measured between 320nm and 360 nm. The sample should not allow more than 10% transmission at any point. (Reported as Pass or Fail ).
Method 2. Transmission of an 8 micron film is measured between 320nm and 360 nm. The film
should not allow more than 10% transmission at any point over the range (Reported as Pass or Fail ).

UVA-UVB Ratio (NUMERICAL) (2004) Absorption of a 0.75mg/sq cm to 1 mg/sqcm film is measured between 290nm and 400nm. The ratio of areas under the curve between 290 - 320 (UVB region) is compared with the area under the curve between 320 and 400nm. Adjustment is made for products with TPF (SPF) above 30, so that they are not disadvantaged. i.e. for above SPF 30, the ratio only needs to be 12. Pre irradiation of the sample IS required. (Calculated as TPF x UVA/UVB). Various substrates can be nominated.

Star Rating (CATEGORIES) (2008) is the method used by Boots in the UK (not mandated). Absorption of a 1 mg/sq cm film is measured between 290nm and 400nm. Pre irradiation of the sample IS required. Rating scale is 3 to 5 stars . More stars means more protection (by ratio) in the UVA area.

Critical Wavelength (PASS/FAIL) is the current proposed in-vitro method for the USA. Absorption of an 0.75 mg/sq cm film is measured between 290 nm and 400 nm. The critical wavelength is the point where 90% of the area under the curve lies, starting at the UVB end. Pre irradiation of the sample IS required. (Reported as SOME (UVA/UVB) - between 340nm and 370 nm , MORE (Broad Spectrum) - above 370nm.

DIN 67502 (UVA Balance)
The methodology is based on that described in the German Standard DIN 67502. The in-vitro SPF is determined using the values provided in the CIE. The in-vivo SPF is applied in order to correct the values obtained in vitro. The in-vitro PPD are derived by applying the values from the PPD Action Spectrum given iun the standard. UVA Balance was arrived at according to the equation ...

COLIPA (UVAPF) (2007) The method is similar to the film sample film presentation and substrate used in determination of Boots Star and DIN. Pre and Post Irradiation values are measured of the sample also must be determined. E.U. Compliance (2007) is also reported.

Proposed FDA (2007) The FDA is proposing new Rules which will are expected to be finalised in 2009 -2010. The current proposal is for a combination of both in-vivo and in-vitro tests and an interpreation of the results.

ISO The method is close to finalisation and Dermatest has been working extensively on the methodology and validation.

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