A 28 Day Clinical Assessment of a Lactic Acid-containing Antimicrobial Intimate Gel Wash Formulation on Skin Tolerance and Impact on the Vulvar Microbiome

Abstract

While intimate feminine hygiene products are widely used as part of daily cleansing routines, little is known about how these products impact the vulvovaginal area and its microbiome stability. This 4 week clinical study assessed tolerance of a novel gel wash containing lactic acid (pH 4.2) for external daily use when used on the external genital area and its effects on skin moisturization, vulvar skin pH, and the vulvar microbiome. After a 7 day pre-study conditioning period, 36 healthy females in three balanced age groups (18–29, 30–44, and 45–55 years) used the gel wash to cleanse their external genital area (mons pubis and vulva) and entire body at least once per day for 28 days. Skin tolerance of the gel wash was assessed by the gynecologist. Effects of the gel wash on vulvar skin microbiota were studied by performing bacterial 16S rRNA and fungal internal transcribed spacer (ITS) microbial richness and diversity analysis. Based on gynecologic assessment after 28 days of use, the gel wash showed acceptable tolerance, with no signs of increased dryness, redness, edema, itching, stinging, or burning. Use of the gel wash was associated with a significant increase in both short-term (single application) and longer-term (daily use for 28 days) skin moisturization. There was no significant change in vulvar skin pH over time with daily product use, and the gel wash did not significantly affect the natural vulvar microbiome species richness or diversity for bacteria or fungi. Results showed that this gel wash is a mild, moisturizing cleanser that maintains the natural pH and microbial diversity of vulvar skin. To our knowledge, this was the first study to assess the effect of an antimicrobial feminine gel wash on the natural pH and vulvar microbiome habitat of the skin using bacterial 16S rRNA and fungal ITS genetic sequencing techniques.

Topical Probiotics for Women’s Urogenital Health: Selection of an Oil-based Carrier

“…A previous study has shown that application of LGR-1 to the vagina can stimulate antimicrobial peptides [42], making it a good choice for this type of application. An advantage of applying live bacteria rather than compounds such as lactic acid [43] is that the probiotic strains can adapt to the environment and produce other substances important to health maintenance.…”

Soap, water, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): an ancient handwashing strategy for preventing dissemination of a novel virus

“…Elevation of skin pH has been demonstrated to cause detachment of commensal microbiota ( Lambers et al, 2006 ). An antibacterial intimate wash formulated with lactic acid was recently demonstrated to stabilize the pH of the vulvar skin, while causing no negative impacts on the richness or diversity of the microbiome ( Bruning et al, 2020 ). When formulating with organic acids, the pH of the formulation and the pKa of the acid must be considered.…”

Emulsion-Based Multicompartment Vaginal Drug Carriers: From Nanoemulsions to Nanoemulgels

“…Based on the anatomical and physiological aspects of the intravaginal drug administration route, the optimal intravaginal formulation should (a) enable the delivery of low molecular weight hydrophilic or lipophilic compounds as they have the highest absorption rates due to their transport mechanism; (b) be partially water-soluble due to the aqueous properties of the vaginal discharge; (c) be easy to administer; (d) have bioadhesive properties in order to prevent washing-out from the vaginal lumen [ 14 , 44 ]. Another influential property of an intravaginal drug formulation is its osmolarity.…”