Iron sequestration on skin: a new route to improved deodorancy

Area of Science:

• Microbiology
• Dermatology
• Cosmetic Science

Background:

• Axillary malodor results from bacterial breakdown of sweat and sebum precursors.
• Conventional deodorants use bactericides, leading to bacterial regrowth and odor.
• Sustained odor control may be achieved by inhibiting bacterial growth without bactericides.

Purpose of the Study:

• To investigate nutrient deprivation, specifically iron (Fe(III)), as a method to inhibit axillary microflora growth.
• To evaluate the efficacy of iron-chelating agents, particularly diethylenetriaminepentaacetic acid (DTPA) and butylated hydroxytoluene (BHT), in controlling bacterial growth and malodor.
• To compare the novel iron-chelating deodorant technology against existing antimicrobial-based systems.

Main Methods:

• In vitro analysis to identify trace metals most impactful on bacterial growth, focusing on iron deprivation.
• In vitro and in vivo testing of iron-chelating agents (DTPA, BHT) for bacterial growth inhibition on skin.
• Clinical evaluation of a DTPA and BHT fortified deodorant in 50 participants over two weeks, assessing bacterial counts and malodor reduction.
• Benchmarking against leading antimicrobial deodorants (Triethyl citrate, Triclosan, Farnesol).

Main Results:

• Iron (Fe(III)) deprivation significantly inhibited bacterial growth in vitro.
• Diethylenetriaminepentaacetic acid (DTPA) effectively inhibited bacterial growth in vitro and on skin.
• The combination of DTPA and butylated hydroxytoluene (BHT) demonstrated superior deodorancy and bacterial reduction compared to DTPA alone.
• Fortified deodorant significantly reduced aerobic bacteria (log 5.75 to log 4.50 cfu cm(-2)) and malodor (P < 0.01).
• DTPA/BHT combination outperformed Triethyl citrate, Triclosan, and Farnesol in efficacy evaluations.

Conclusions:

• Iron chelation, combined with an agent to liberate iron from transferrin, offers a novel and effective strategy for inhibiting axillary bacterial growth.
• This new deodorant technology provides significant deodorancy benefits, surpassing traditional antimicrobial approaches.
• The axillary microflora profile was maintained, with rapid return to baseline levels post-use, indicating a non-disruptive mechanism.