Comparison of UVA Protection Factor Measurement Protocols

Figures & data

Table 1 In vivo UVA-PF Determination Protocol Comparison

Standard Items	CEN 2006	FDA 2007
Manufacturer country	European Union–South Africa–Japan	United States
UVA protection measurement test type	PPD	PPD
Selection criteria for participants	Skin type 2, 3, 4. 41 ≥ITA≥ 20 Age: between 18 and 60 Type: Caucasian	Skin Type 2, 3
Number of participants	Minimum: 10 Maximum: 20	Minimum: 20 Maximum: 25 persons (20 valid result)
Reference sunscreen formulations	5% de butyl methyl dibenzoyl methane (BMDM), 3% diethyl hexyl methoxycinnamate (EHMC)	Padimate o/Oxybenzone
UVA-PF value of reference sunscreen formulations	4.5 ± 0.5	3.2 ± 0.5
Test site size	Minimum: 30 cm^2 Maximum: 60 cm^2	Minimum 50 cm^2
Distances between borders of test sites	1 cm	1 cm
Test subsite size	Circles with an 8 mm diameter	1 cm^2
Distances between borders of test subsites	Indistinctive	1 cm
Loading dose amount	2 mg/cm^2 ± 2.5%	2mg/cm^2
Waiting period between sunscreen application and UV exposure	15 to 30 minutes	At least 15 minutes
Radiation device specifications	150 or 300 watts xenon lamp that forms a integrate spectrum from 320nm to 400nm. UVA2/UVA1 = 8–20%	A lamp which forms a continuous spectrum from 320nm to 400nm. The UVA2 radiation has to be 8 to 20 percent of total UVA radiation. The illumination source radiation from 250nm to 320nm have to be less than 0.1% from 320nm to 400nm.
Exposure trend	For MPDU site a series of 5 doses; 8, 10, 12, 15, 19 and 25 J/m^2 is used. For MPDP site the same dose series that multiplied in expected UVA-PF are used for the time of exposure.	For MPDU site a series of 5 doses with incremental geometric progression 1.25 shall be used. For MPDP site the dose series 0.64x, 0.80x, 1.00x, 1.25x and 1.56x are used which x is expected UVA-PF of the product.
Periodical inspection of the lamp	At least annually	Every 6 months
Time of MPD evaluation	2 to 4 hours after last exposure	3 to 24 hours after last exposure
MPD assessment condition	Minimum 450 lux illumination	450 to 550 lux illumination

Table 2 In vitro UVA-PF Determination Protocol Comparison

Standard Items	CEN	FDA 2007	FDA 2011	ISO 24443
Manufacturer country	European Union–South Africa–Japan	United States	United States	European Union
UVA protection measurement test type	Critical wavelength	Modified Diffey fraction	Critical wavelength	In vitro UVA-PF measurement consistent with PPD
Plate numbers	Minimum 5 plates	Minimum 5 plates	Minimum 3 plates	Minimum 4 plates Maximum 10 plates
Plate genus	Artificial hydrated collagen (based on the Diffey method 2000) and epidermal skin, transpore tape (based on the Diffey method 1994)	Quartz	PMMA	PMMA
Size of product loading area	10.2 cm	Not determined	16 cm^2	16 cm^2
Reference sunscreen formulations	Does not have	Does not have	Does not have	S2 reference sunscreen
Radiation source	Xenon arc simulator 1000 Watt which equipped with optical filters	A solar simulator	A device that has a continuous spectrum of 290 nm to 400 nm.	A radiation source that produces UV spectra from 290nm to 400nm in an energy range of 40 to 2200 w/m^2 and the UVA to UVB ratio should be 8 to 22.
Wavelength intervals between measurement operations	1 nm	5 nm	1 nm	1 nm
The dynamic range of the spectrometer	Indistinctive	Indistinctive	2.2 absorbance unit	2.2 absorbance unit
Product loading amount	2 mg/cm^2	2 mg/cm^2	0.75 mg/cm^2	1.3 mg/cm^2
Product distributing manner	Indistinctive	10 seconds spreading using a finger cot	2 phase spreading (firstly 30 seconds with mild pressure and then 30 seconds with high pressure) using a finger cot	2 phase spreading (firstly 30 seconds With rotational movements with mild pressure and then 20 to 30 second With vertical and horizontal movements with high pressure) without using a finger cot
Pre-irradiation dose	product expected SPF	product expected SPF	Pre irradiation dose equivalent to 4 MEDs	UVA-PF0
Number of radiation passing measurement	8 times from 5 pages in other words 40 times	12 times from 5 pages in other words 60 times	3 times from 5 pages in other words 15 times	Indistinctive