Skin permeation enhancement effects of the gel and whole-leaf materials of Aloe vera, Aloe marlothii and Aloe ferox

Objectives The aim of this study was to investigate the in‐vitro permeation enhancement effects of the gel and whole‐leaf materials of Aloe vera, Aloe marlothii and Aloe ferox using ketoprofen as a marker compound. Methods The permeation studies were conducted across excised female abdominal skin in Franz diffusion cells, and the delivery of ketoprofen into the stratum corneum‐epidermis and epidermis‐dermis layers of the skin was investigated using a tape‐stripping technique. Key findings A. vera gel showed the highest permeation‐enhancing effect on ketoprofen (enhancement ratio or ER = 2.551) when compared with the control group, followed by A. marlothii gel (ER = 1.590) and A. ferox whole‐leaf material (ER = 1.520). Non‐linear curve fitting calculations indicated that the drug permeation‐enhancing effect of A. vera gel can be attributed to an increased partitioning of the drug into the skin, while A. ferox whole leaf modified the diffusion characteristics of the skin for ketoprofen. The tape stripping results indicated that A. marlothii whole leaf delivered the highest concentration of the ketoprofen into the different skin layers. Conclusions Of the selected aloe species investigated, A. vera gel material showed the highest potential as transdermal drug penetration enhancer across human skin.