Pharmacy and Pharmaceutical Technology Department, Faculty of Pharmacy, University of Barcelona, Joan XXIII avenue, 08028 Barcelona, Spain.
J Dermatol Sci. 2013 Mar;69(3):202-14. doi: 10.1016/j.jdermsci.2012.10.013. Epub 2012 Oct 30.
Melatonin has attracted attention because of their high antioxidant and anticarcinogenic activity. Otherwise, the use of sunscreens is recommended for patients after chemotherapy and radiotherapy treatments or to prevent UV radiation-induced skin damages that may result in pre-cancerous and cancerous skin lesions.
To evaluate the beneficial influence of melatonin in topical sunscreen emulsions combined with three common ultraviolet filters.
After the formulation characterization in terms of rheology, stability studies were performed. Release studies let us to evaluate its mechanism of delivery and ex vivo permeation study through human skin, the amount of melatonin retained. The antioxidant activity assay was also carried out, and finally the in vivo photoprotective effect in rats was tested as transepidermal water loss and erythema formation.
The rheological behaviour of formulations was pseudoplastic fluid, all emulsions had good physical stability. Release studies showed a trend of enhancement in melatonin release from emulsions incorporating UV filters and followed a Weibull model. Melatonin permeation was higher from the emulsion containing melatonin combined with a mixture of three ultraviolet filters (MMIX) formulation. Equally this formulation exhibited the highest radical scavenging activity. Finally the photoprotective assay showed that only skin areas treated with this formulation were statistically equivalent to the unirradiated control area.
MMIX formulation would be a promising formulation for preventing the undesirable adverse effects of UV skin irradiation because melatonin not only acts as a potent antioxidant itself, but also is capable of activating an endogenous enzymatic protective system against oxidative stress.
褪黑素因其具有高抗氧化和抗癌活性而受到关注。此外，建议在化疗和放疗治疗后或为了预防可能导致癌前和癌变皮肤损伤的紫外线辐射对皮肤的损伤，使用防晒霜。
评估褪黑素在含有三种常见紫外线滤光剂的局部防晒霜乳剂中的有益影响。
对制剂的流变性进行了配方特征描述，并进行了稳定性研究。释放研究使我们能够评估其传递机制，并通过人体皮肤进行了体外渗透研究，以评估其在人体皮肤中的保留量。还进行了抗氧化活性测定，最后在大鼠中进行了体内光保护作用测试，如经表皮水分流失和红斑形成。
制剂的流变行为为假塑性流体，所有乳剂均具有良好的物理稳定性。释放研究表明，从含有紫外线滤光剂的乳剂中增强了褪黑素的释放趋势，并且遵循 Weibull 模型。从含有褪黑素和三种紫外线滤光剂混合物的 MMIX 制剂的乳剂中，褪黑素的渗透更高。同样，该制剂表现出最高的自由基清除活性。最后，光保护试验表明，只有用该制剂处理的皮肤区域在统计学上与未照射的对照区域相当。
MMIX 制剂将是一种有前途的预防紫外线皮肤照射不良影响的制剂，因为褪黑素不仅本身具有强大的抗氧化作用，而且还能够激活针对氧化应激的内源性酶保护系统。
