Quantification of skin-colour changes induced by topical corticosteroid preparations using the Minolta Chroma Meter.

The Minolta tri-stimulus colorimeter CR-200 was used to quantify the blanching effect of topical corticosteroids in a non-occluded vasoconstriction test. To investigate the influence of time on variations in colorimetric parameters, an initial series of measurements was performed on Day 1 on six predetermined sites on the ventral surface of the forearm of six healthy volunteers every 2 h over a 12-h period. The colorimetric values were shown to be site related but hourly variations occurred with similar profiles for all the sites. On Day 2, four topical corticosteroid creams, representative of their potency groups, as well as a base were applied in a randomized double-blind manner on five of the predetermined sites. Visual gradings and colorimetric measurements were carried out every 2 h over the following 12-h diurnal period and were continued on Day 3. The colorimetric parameters L* (luminance) and a* (colour hue ranging from green(-) to red(+] gave a rank order correlated to corticosteroid potency that showed superior discrimination compared to simple visual grading. In this study, L* was more discriminative parameter than a*. The Minolta Chroma Meter CR-200 appears to be a simple and accurate device for objectively measuring the blanching effects of topical corticosteroids.