Experimental Design
Ethical approval (Ref No:
160614243, 01 July 2016) was obtained from Pharma-Ethics (Pty) Ltd.
research ethics committee
(Lyttelton Manor, South Africa),
in compliance with the 1964 Declaration of Helsinki and its subsequent
amendments. The study was
conducted in accordance with the
FDA’s VCA guidance (22) as described in a previously published study by
Zvidzayi et al (26). A 10μL dose of the relevant creams were
applied to demarcated sites on the ventral surface of the arms of each
subject and left on for the relevant dose durations (i.e. , at 5,
10, 20, 40, 60, 90, and 150 min).
The products were removed from the
application sites after the relevant dose durations using cotton swabs,
3 wet wipes (warm water) followed by 2 dry wipes. Chromameter (Model CR
400, Minolta®, Osaka, Japan) readings at all sites
were taken over 24 h by a single chromameter operator. Only the a-scale
data were used in the statistical analysis in accordance with the FDA
guidance (17,26–28).