Sun protection strength of a hydroquinone 4%/retinol 0.3% preparation containing sunscreens.
BACKGROUND
Dyschromias are common and significantly impact patients' quality of life. Formulas containing hydroquinone 4% are effective in these conditions. Since exposure to ultraviolet radiation (UVR) can worsen disease and complicate treatment, the incorporation of sunscreens can avert this problem.


METHODS
We tested the sun protection factor of a hydroquinone formulation (Lustra-Ultra, TaroPharma, Hawthorne, NY) containing avobenzone 3%, and octinoxate 7.5% according to the FDA Sunscreen Monograph on 20 volunteer subjects. We also determined the UVR absorbance spectrum of the preparation.


RESULTS
The mean sun protection factor (SPF) of 21.7 satisfied labeling requirements for SPF 20. The formulation exhibited strongest photoprotection near the wavelengths of peak sun burning effectiveness in the UVB region and maintains significant UVR absorbance through the entire UVA region.


CONCLUSIONS
Avobenzone 3% and octinoxate 7.5% provide broad spectrum UV protection. Incorporating these sunscreens into a hydroquinone preparation simplifies the treatment regimen while providing significant photoprotection for patients being treated for dyschromia.
Stanfield
Joseph W
JW
Suncare Research Laboratories, LLC, Winston-Salem, NC, USA.
Feldman
Steven R
SR
Levitt
Jacob
J