Comparison of anti-wrinkle clinical efficacy of transdermal preparations contained sodium ascorbyl phosphate and ascorbic acid in Human volunteers
Introduction: Vitamin C has the effects on skin rejuvenation. Objective: Clinical evaluation to compare the anti-wrinkling effects of transdermal emulgel products containing sodium ascorbyl phosphate and ascorbic acid in healthy human volunteers. Method: The formulations with specific percentages of sodium ascorbyl phosphate and ascorbic acid were prepared and studied clinically on 12 volunteers respectively. Improvement of skin elastisity by elastometr device and improvement of wrinkles by clinical examinations and imaging with specific enlargement by kctechnology device were measured and analysis following images by ImageJ software was carried out before and after treatment and every 2 weeks. HPLC method was used to evaluate the stability of the formulation. Results: Although sodium ascorbyl phosphate expected to have a greater impact in improving elasticity and wrinkles compared to ascorbic acid but statistically significant difference in efficacy of the products was not observed. Howewer the formulations containing ascorbic acid and sodium ascorbyl phosphate both improved elasticity and wrinkles of the skin. HPLC results showed that the amount of sodium ascorbyl phosphate in formulation was decreased over time and antioxidant should be added and the best stabilizing condition is keeping in a cool place and away from light. Ascorbic acid with addition of antioxidants and kept in the refrigerator, was quite stable for 2 months. The color change of the formulation containing sodium ascorbyl phosphate was less compared to ascorbic acid even though antioxidants added in the formulation containing ascorbic acid. Conclusion: Efficacy of antiaging of both sodium ascorbyl phosphate and ascorbic acid regarding elasticity and roughness of skin was confirmed but the effectiveness of these two products did not show a significant difference. Formulation containing sodium ascorbyl phosphate is more stable than ascorbic acid only in terms of appearance property.