Formulation and evaluation of a water-in-oil cream containing herbal active ingredients and ferulic acid

Abstract

Background and aims: The main aims of the present study were to formulate an anti-age cream based on vegetal ingredients and ferulic acid and to evaluate the physical characteristics and the efficacy of the cream.

Methods: The active ingredients were Centella asiatica oil, Spilanthes acmella oil, Zingiber officinale extract and ferulic acid. Formulation 1 (F1) was prepared using glyceryl stearate and Ceteareth-25® as emulsifiers and Formulation 2 (F2) using glyceryl stearate and potassium cetyl phosphate, all other ingredients remaining the same. The physical characterization of the creams was performed and the following parameters were analyzed: viscosity, oil droplet size, polydispersity index; also, texture analysis was performed. The anti-aging effect of the F2 was evaluated by assessing the cutaneous density before and after cream application using DUB-cutis® scanner.

Results: The mean diameter of oil drops was 10.26±4.72 mm (F1) and 22.72±7.93 mm (F2) and the polydispersity index was 35.4% and 45.7%, respectively. The mean values for consistency were 594.7±10.3 g (F1) and 300.5±14.5 g (F2), the average values for adhesion were 15.61±0.8 mJ (F1) and 22.25±4.3 mJ (F2), for firmness were 51.2±0.8 g (F1) and 30.3±4.3 g (F2) and the spreadability had values between 72.63 mm2 (F1) and 73.3 mm2 (F2). In vivo study revealed that the mean values of the cutaneous density increased from 9.21±1.39 % to 12.50±1.44 % after 8 weeks of cream application. The herbal ingredients incorporated in the O/W cream base for the antioxidant activity and anti-wrinkle effect, induced changes of the cutaneous density, an important parameter which quantifies the regeneration process of the skin.

Conclusions: An anti-age cream containing herbal active ingredients and ferulic acid with appropriate physical characteristics was obtained. In vivo study of clinical efficacy revealed a positive effect on skin density, which increased after 8 weeks of cream application.

Keywords: O/W cream; anti-age; herbal extracts; texture analysis; ultrasound skin imaging.

Figure 1

Ultrasonografic aspect of skin (DUB® cutis, Lüneburg, Germany).

Figure 2

Viscosity of the two creams (cP) vs. shear rate (s-1).

Figure 3

Texture profile plot of the creams: F1 (orange) compared with F2 (black); (a) - consistency, (b) - firmness, (c) - spreadability.

Figure 4

Ultrasonographic aspect of the skin before and after 8 weeks of cream application.

Figure 5

Relative change of the skin density (%) after 4 and 8 weeks(zygomatic area, mean values±SE, N=10).