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To consider very important the efforts that have being done and follow doing to develop
new methodologies for measuring sunscreen ultraviolet A protection factors, specially the latest
in vitro testing, since that in vivo methodologies have limitations and may endanger human vol-
unteers health. The Spectroscopy Labsphere Transmittance Analyzer, is a very useful technol-
ogy, due to have created a new photoprotective magnitude Oc or CW (Critical Wavelenght),
that not only quantifies UV-A (320-400nm) protection levels, but that lets at the same time, to
obtain SPF in vitro, and UV-A/UV-B attenuation ratios too, in accordance with British Guid-
ance.

To appreciate the CTFA (Cosmetic, Toiletry & Fragrance Association) Proposition to
FDA, 1997, conditioning as valid the attribute B.S.P. (Broad Spectrum Protection), when Oc
(CW) t 370nm, with the complementary recommendation avoiding to use higher SPFs without
a equilibrated attenuation on UV-A spectrum. This methodology that we have used to evaluate
sunscreens SPF 30+ or SPF 30 Plus, with broad and equilibrated attenuations all over the ultra-
violet spectrum, also we have used it, to qualify F.S.P. (Full Spectrum Protection), a photopro-
tective attribute advised for extremely photosensitive skin and exigent photodermatoses to pre-
vent and to treat.

Finally, to promote that all sunscreens labels, have clear information about the photoprotec-
tion level, not only against sunburn as SPF do it very well, but qualifying the photoprotective
information on UV-A range, recommending to use Oc or CW, in addition to the specification
B.S.P. or F.S.P. as appropriate, in order to give information to physicians, pharmacists, users,
and to encourage a better clinical pharmacy skin photodamage understanding.

Key words: Skin photodamage.Sunscreens.Photodermatoses.Clinical pharmacy.

El sol es una fuente contínua de emisión de radiaciones electromagné-
ticas, con diferentes longitudes de onda O, lo que permite definir rangos
de radiaciones, como el ultravioleta (200-400nm), el visible (400-800nm),
el infrarrojo !800 nm, y otros de menor interés fotobiológico.

No toda la radiación emitida por el sol, atraviesa la estratósfera, lo que
determina que las radiaciones con longitud de onda menor de 200 nm,
queden retenidas, como la radiación ultravioleta UV-C (200-290nm), y
radiaciones más tóxicas, como RX, RJ, Rcósmicos.

El espectro ultravioleta que atraviesa la estratósfera (290-400nm) es
de gran interés farmacéutico clínico y en atención a sus efectos, se divide
en dos grandes rangos UV-B (290-320nm) y UV-A (320-400nm), subdi-
vidido este último por razones biológicas, en UV-A II (320-340nm) y
UV-A I (340 –400nm).

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