De Rie M A, Di Nuzzo S, Brands S, Hansen A B, Bos J D
Department of Dermatology, Academic Medical Centre, University of Amsterdam, PO Box 22700, 1100 DE Amsterdam, The Netherlands.
Br J Dermatol. 2000 Jun;142(6):1160-5. doi: 10.1046/j.1365-2133.2000.03542.x.
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.
应用卡泊三醇可改善紫外线（UV）B光疗的效果，但尚需开展研究以确定两种治疗方法的联合方式。在一项针对37名健康成年志愿者的单盲随机赋形剂对照研究中，我们研究了卡泊三醇软膏（50μg g-1）和卡泊三醇乳膏（50μg g-1）应用后UVB的效果，并确定了卡泊三醇与UVB光疗（280 - 350nm）联合应用的最佳时间。卡泊三醇软膏或乳膏在距UVB照射不同时间间隔时随机涂于背部五个区域。一个区域不进行处理作为对照。涂抹时间分别为照射前一晚、照射前早晨、照射前2小时、照射前即刻以及照射后即刻。通过TL20W/12荧光灯管以递增剂量（20、25、32、40、50和64mJ cm-2）对每个测试区域的六个亚区域进行UVB照射。由一名盲法研究者在UVB照射24小时后进行临床评估。分别对19名和18名受试者应用卡泊三醇软膏和乳膏，并对每个涂抹时间的红斑进行测量并量化。我们发现，与所有其他涂抹时间相比，在照射前即刻应用卡泊三醇软膏或乳膏时，红斑反应明显较小。为解释这些发现，开展了一项赋形剂对照研究。卡泊三醇药物与赋形剂对照之间在红斑方面未见差异。对卡泊三醇乳膏和软膏的分光光度分析显示在UVB范围内无紫外线吸收。未观察到光敏迹象。总之，如果在光疗前即刻应用，卡泊三醇软膏和乳膏的赋形剂可抑制UVB照射引起的红斑诱导。因此，卡泊三醇软膏和乳膏不应在UVB照射前直接应用；然而，它们可在UVB照射前2小时或照射后即刻的任何时间应用。讨论了这种防晒活性的可能解释。
