MALDI Mass Spectrometry Imaging and Semi-Quantification of Topically Delivered Lactic Acid

Area of Science:

• Dermatology
• Analytical Chemistry
• Biochemistry

Background:

• Lactic acid is a key ingredient in topical skincare.
• Measuring its skin delivery is difficult due to high endogenous levels.
• Novel methods are needed to accurately assess topical lactic acid penetration.

Purpose of the Study:

• To develop a quantitative and qualitative method for measuring lactic acid delivery into the skin.
• To analyze lactic acid penetration from diverse skincare formulations.
• To overcome challenges posed by endogenous lactic acid in skin.

Main Methods:

• Utilized matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI).
• Employed a triple isotope of lactic acid (L-Lactic acid-13C3) for signal resolution.
• Analyzed porcine skin samples treated with lactic acid skincare products.

Main Results:

• Successfully resolved topical lactic acid from endogenous background signals using L-Lactic acid-13C3.
• Enabled quantitative and qualitative analysis of lactic acid distribution in skin sections.
• Demonstrated the efficacy of MALDI-MSI for analyzing lactic acid delivery from various products.

Conclusions:

• The combined use of L-Lactic acid-13C3 and MALDI-MSI provides a robust method for measuring topical lactic acid delivery.
• This approach accurately quantifies and qualifies lactic acid penetration into the skin.
• Future research can leverage this method to elucidate lactic acid's mode of action in skincare.