Visually Indicating Wipe Efficacy and Other Topics: Literature Findings

By: Charles Fox, Independent Consultant

Posted: December 30, 2009, from the January 2010 issue of Cosmetics & Toiletries.

This month’s survey of recent patent and research literature describes moneymaking ideas for personal care product development, including enhancing avobenzone photostability in the presence of zinc oxide with a phosphate-based emulsifier, adding value to sunscreen protection with antioxidants, indicating wipe efficacy visually, and using Heat Shock Protein 27 for antiaging, among others.

Skin and Skin Care
Antiaging clinical efficacy: Watson et al. have published on the clinical efficacy of a cosmetic antiaging product.¹ Few over-the-counter (OTC) antiaging products have been subjected to rigorous double-blind, vehicle-controlled efficacy trials. The authors had previously observed that the application of an antiaging product to photoaged skin under occlusion for 12 days stimulated the deposition of fibrillin-1, suggesting its potential to repair and possibly improve photoaged skin. The researchers therefore examined a similar OTC antiaging product using a patch test assay over a 6-month, double-blind randomized controlled trial (RCT), with a further 6-month open phase to assess the clinical efficacy in photoaged skin.

For the patch test, a commercially available test product and its vehicle were applied, occluded for 12 days to photo-aged forearm skin (n = 10) prior to biopsy, and fibrillin-1 was immunohistochemically assessed. All-trans retinoic acid (ATRA) was used as a positive control. Sixty photoaged subjects were recruited to the RCT, and the test product and vehicle (n = 30) were applied once daily for six months to the face and hands. Clinical assessments were performed at recruitment and following 1, 3 and 6 months of use. Skin biopsies of twenty-eight volunteers were taken (test product n = 15; vehicle n = 13) for immunohistochemical assessment of fibrillin-l from the dorsal wrist at baseline and after six months of treatment. All volunteers received the test product for six additional months and final clinical assessments were performed at the end of this open period.

In the 12-day patch test assay, the researchers observed significant immunohistological deposition of fibrillin-1 in skin treated with the test product and ATRA, compared with the untreated baseline (P = 0.005 and 0.015, respectively). In the clinical RCT, the test product significantly improved facial wrinkles at six months, compared with the baseline assessment (P = 0.013), whereas vehicle-treated skin was not significantly improved (P = 0.11).

After 12 months, a significant benefit of the test product over that projected for the vehicle was observed, where 77% vs. 33% of test subjects improved, respectively (combined Wilcoxon rank tests P = 0.026). Significant deposition of fibrillin-1 in the skin treated with the test product for 6 months also was noted. This demonstrates that a cosmetic product can produce significant improvement in the appearance of wrinkles and further supports the use of fibrillin-1 as a robust biomarker for the repair of photoaged dermis.