Calcipotriol ointment and cream or their vehicles applied immediately before irradiation inhibit ultraviolet B-induced erythema

Abstract

Results of ultraviolet (UV) B phototherapy can be improved by the application of calcipotriol, but studies are needed to decide how the two treatments should be combined. We studied the effect of UVB after application of calcipotriol ointment (50 microg g-1) and calcipotriol cream (50 microg g-1) and determined the optimal time of application of calcipotriol when combined with UVB phototherapy (280-350 nm), in a single-blinded randomized vehicle-controlled study of 37 healthy adult volunteers. Calcipotriol ointment or cream was applied randomly on five areas on the back at different time intervals from UVB irradiation. One area was left untreated as the control. Application times were the evening before, the morning before, 2 h before, immediately before, and immediately after irradiation. UVB irradiation was administered by TL20W/12 fluorescent tube lamps at increasing doses (20, 25, 32, 40, 50 and 64 mJ cm-2) to six subunits of each test area. Clinical assessment was performed 24 h after UVB irradiation by a blinded investigator. Calcipotriol ointment and cream were applied in 19 and 18 subjects, respectively, and erythema was measured for each application time quantified. We found that erythemal reactions were significantly smaller when calcipotriol ointment or cream was applied immediately before irradiation compared with all other application times. To explain these findings, a vehicle control study was performed. No difference in erythema was seen between calcipotriol medication and the vehicle controls. Spectrophotometric analysis of the calcipotriol cream and ointment showed no UV absorbance in the UVB range. No signs of photosensitization were noted. In conclusion, the vehicles of the calcipotriol ointment and cream inhibit the induction of erythema by UVB irradiation if applied immediately before phototherapy. Consequently, calcipotriol ointment and cream should not be applied directly before UVB irradiation; however, they may be applied at any time up to 2 h prior to or immediately after UVB irradiation. Possible explanations for this sunscreen activity are discussed.

Narrowband ultraviolet B phototherapy and 308-nm excimer laser in the treatment of vitiligo: A review

“…63 Both calcipotriene and its vehicle have been reported to have a photoprotective effect. 64,65 Therefore, they should not be applied immediately before irradiation. They may be applied at any time up to 2 hours before or immediately after irradiation.…”

Vitamin D Supplementation Does Not Improve the Severity or the Resolution of Ultraviolet B-Induced Acute Erythema

“…Two hours after application, the MED returned to baseline [26] . In contrast, when calcitriol or calcipotriol was applied 24 [22] , 12 [23] , or 2 h before [24] or immediately after [22] irradiation, there was no influence on the UVB-induced erythema [22][23][24] . Nevertheless, when applied directly after UV exposure, it decreased the density of sunburn cells and the number of thymine dimers [16,22] .…”

“…Several studies have examined the clinical effect of topical calcitriol [22] or calcipotriol [23][24][25][26] on the MED in humans, and the results are contradictory. Calcipotriol is a synthetic derivative of calcitriol and it is known to display similar properties in terms of epidermal proliferation, modulation of keratinization, and inflammation [25] .…”

“…The delay between topical application and UV irradiation varies among studies, potentially influencing the MED. In brief, calcipotriol 0.005% [23][24][25][26][27] applied 15-20 min [25,27] or immediately before [23,24,26] irradiation, with a thick enough layer [23] , influenced the MED [23][24][25][26][27] , which could reach an increase of 31% [27] or an increase from 22.6 to 54.6 mJ/cm 2 [23] . Two hours after application, the MED returned to baseline [26] .…”

Topical Agents for the Treatment of Psoriasis, Past, Present and Future

“…26 These studies are complicated by the fact that application of calcipotriol ointment or cream decreases UVB-induced erythema, a phenomenon that has been attributed to the vehicle. 27,28 In addition, UVA exposure has been reported to decrease the amount of measurable calcipotriol after topical application, 27 therefore, calcipotriol should not be applied immediately before PUVA therapy or UVB phototherapy.…”