Comprehensive Evaluation And Mechanism Study On The Efficacy Of 10% Nicotinamide Combined With 30% Supramolecular Salicylic Acid In The Treatment Of Female Melasma

Objectives: To comprehensively evaluate the efficacy of 10% nicotinamide combined with 30% supramolecular salicylic acid on the treatment of female melasma,and to study its mechanism.Methods: The first part adopts the method of double-blind,randomized,parallel-group.Sixty female patients with melasma were divided into the experimental group and the control group with 30 cases in each group.The experimental group was given 10% nicotinamide twice a day and 30% supramolecular salicylic acid once every two weeks for 16 consecutive weeks.The control group was treated with 10%nicotinamide simulation drug and 30% supramolecular salicylic acid simulation drug,using the same treatment method.The main efficacy indicators were: modified Melasma Area and Severity Index Score(m MASI)and total effective rate;Secondary efficacy indicators were: skin image evaluation(VISIA images and skin confocal microscopic images),skin melanin assessment(melanin index),skin brightness assessment(Lab color L * value,a * value,b * value),the skin barrier assessment(transdermal water loss,cuticle water content,skin lipid content),self-symptom assessment,psychological assessment;adverse reactions assessment.In the second part,the subjects were immortalized normal melanocytes(PIG1).MTS method was used to measure the effect of different concentrations of nicotinamide and salicylic acid on melanocyte activity,DOPA colorimetry was used to measure tyrosinase activity,and Na OH dissolution method was used to measure melanin content,the morphological and structural changes of melanocytes were observed under a microscope.Statistical analysis of the data,a P-value <0.05 was considered to be statistically significant.Results: In the first part,the main efficacy indicators: the overall m MASI value of the experimental group was significantly lower than that of the control group(P<0.01),and the effective rate of the experimental group was 60% and 3.3%,respectively.The effective rate of the experimental group was significantly better than that of the control group(P<0.01).Secondary efficacy indicators: after treatment,the area and severity of VISIA pigmented spots,ultraviolet pigmented spots and brown pigmented spots gradually decreased in the experimental group,and pigment particles were reduced and sparsely distributed in skin confocal microscopic images,while no significant changes were observed in VISIA and skin confocal microscopic images in the control group.The total value of the melanin index in the experimental group was significantly lower than that in the control group(P<0.01).The total value of transdermal water loss in the experimental group was lower than that in the control group(P<0.01).There was no difference in the initial self-assessment score of melasma symptoms between the two groups,while the final score of the experimental group was lower than that of the control group(P<0.01).There was no difference in the initial score of the self-rating depression scale between the two groups,and the final score of the self-rating depression scale in the experimental group was lower than that in the control group after treatment(P= 0.019);There was no difference in the initial score of the self-rating anxiety scale between the two groups,while the final score of the self-rating anxiety scale in the experimental group was lower than that in the control group after treatment(P=0.038).There were no significant differences in skin brightness(Lab color L * value,a * value,b * value)and skin barrier(cuticle water content,skin lipid content)between the two groups.The incidence of adverse reactions was 3.33% in the experimental group,and no obvious adverse reactions were observed in the control group.In the second part,the inhibitory effects of nicotinamide and salicylic acid on melanocyte activity were time and concentration-dependent.1.25 mg/ m L nicotinamide and 100 μM salicylic acid could safely and effectively inhibit the activity of normal human melanocytes.The effect of nicotinamide combined with salicylic acid on reducing tyrosinase activity and melanin content in melanocytes was better than that of nicotinamide or salicylic acid alone(effect:nicotinamide combined with salicylic acid > niacinamide > salicylic acid).After niacinamide combined with salicylic acid treatment,melanocytes became round,cell spacing increased,dendrite length of melanocytes decreased(P<0.05),and the number of melanocyte dendrites decreased.Conclusions: The effective rate of 10% nicotinamide combined with 30%supramolecular salicylic acid in the treatment of female melasma was 60%.After treatment,m MASI,melanin index,and transepidermal water loss of the patients were significantly reduced.The patient’s self-assessment of melasma symptoms improved well,and the patient’s psychological assessment of depression symptoms and anxiety symptoms improved.The patient had a good tolerance to treatment,and the incidence of adverse reactions was 3.33%.Nicotinamide and salicylic acid inhibited melanocyte activity,decreased tyrosinase activity and melanin content in melanocytes,and regulated melanocyte morphology and structure.The effect of the combined application is greater than that of a single application.