Characterization of Commercially Available Vaginal Lubricants: A Safety Perspective

Abstract

Vaginal lubricants are widely used by women to help solve intercourse difficulties or as enhancers, but recent reports raise questions about their safety. Twelve commercially available gel products were tested for pH value, pH buffering capacity, osmolality and cytotoxicity relevant to vaginal delivery. Obtained data were analyzed in light of the recent Advisory Note by the World Health Organization (WHO) for personal lubricants to be concomitantly used with condoms. Results showed that most products do not comply with pH and osmolality recommended standards, thus posing a potential hazard. Four products presented values of osmolality around three-times higher than the maximum acceptable limit of 1200 mOsm/kg. In vitro cell testing further identified substantial cytotoxicity even at 1:100 dilutions for three products, contrasting with no significant effect of up to at least a 1:5 dilution of a Universal Placebo gel. However, no direct correlation between these last results and pH or osmolality was found, thus suggesting that the individual toxicity of specific formulation components plays an important role in the outcome of a particular product. Although further assessment is required, these results highlight potential safety issues related to the formulation of commercially available vaginal lubricants.

Treating vulvovaginal atrophy/genitourinary syndrome of menopause: how important is vaginal lubricant and moisturizer composition?

“…In healthy adults, normal vaginal and rectal pH ranges are 3.8–4.5 and ∼7.0, respectively 30 , and the optimum requirements for both vaginal and rectal intercourse cannot be bridged in a single lubricant. Cunha and colleagues commented that 'outcomes of low pH are even less understood, but animal data suggest that values of 3 or less are unacceptable for human use' 39 . Therefore, clinicians need to be aware that some preparations do not meet this recommendation (see Table 1 ).…”

“…Although cytotoxic effects associated with hyperosmolar lubricants have been demonstrated in vitro and in humans in several studies 36–38 , a recent study of 12 commercially available lubricants of varying pH and osmolalities failed to find a significant association between these criteria and cytotoxicity 39 . The authors suggested that individual components of the surveyed personal lubricants therefore may have a greater influence on cytotoxicity than pH or osmolality, and added that 'further specific toxicity testing using vaginal microbiota, namely Lactobacillus spp., is advisable' 39 .…”

What do Portuguese Women Prefer Regarding Vaginal Products? Results from a Cross-Sectional Web-Based Survey

“…The perception by the general population that natural products are safer may account for these observations [ 41 ]. Therefore, more important than complying with the preference for ingredients of natural origin, formulators should be particularly careful with safety aspects of vaginal products [ 42 ].…”

New strategies for local treatment of vaginal infections

“…Another nanotechnology-based drug delivery systems are based on liposomes, the first nanoparticles to undergo translation into clinical practice, that are now currently available as marketed formulations, including vaginal preparations to be used as lubricants [170]. These lipid nanoparticles are based on bilayered phospholipid membranes that can be modified by coating with polymers or other molecules for targeted drug release [171].…”