Despite the suggestions that some OTC lubricants have potential microbicidal activity, our evaluation of TI values for HIV-1 infection and more extensive toxicity testing of 41 lubricants—which is the majority of those identified as commonly-used in a survey of anal sex lubricant users—suggested otherwise.10
A few personal lubricants showed mild antiviral activity against HIV-1MN
, but none offered the level of protection afforded by the in vitro
positive control Carraguard. Strikingly, not only did most not have antiviral activity, we identified four that dramatically amplified replication of both R5 and X4 HIV-1 strains. Previous studies documented anti-HIV-1 activity of Astroglide brand lubricants,10
but based on our findings, this appears to be due to the toxic effect of the product and not true antiviral effect. As seen in N-9 studies,5,6
although a compound has the potential to inactivate free HIV-1 particles and disrupt the cellular membrane of cells infected with HIV-1, the potential toxic effects outweigh the potential benefits. Herein we document that most of the 41 lubricants tested exhibited TI values that reflected the impact of cellular toxicity and not specific antiviral activity.
Recent studies have also shown a correlation between lubricant osmolality and rectal toxicity.6
Supporting this conclusion, our results show that a majority of the lubricants reduced the electrical resistance passing through the cellular monolayer indicating a loss of integrity, which may potentially increase the chances of HIV-1 transmission in vivo
. Interestingly, a recent report showed that hyperosmolar formulations and surfactants such as GML (glycerol monolaurate) markedly increased the susceptibility of mice to HSV-2.17
Additionally, high levels of EDTA (a common ingredient in several lubricants) tended to increase the susceptibility of mice to HSV-2.17
Similarly, another group has reported that hyperosmolar lubricants are associated with cellular toxicity.18
A recent study also revealed that the use of some rectal lubricant products might increase susceptibility to rectal STIs. Specifically, 11.7% of subjects using lubricants tested positive for rectal STIs compared to only 4.5% of those who did not use lubricants.19
Thus, certain lubricant formulations may increase the transmission of STIs that are known to enhance the spread of HIV.
An extraordinary observation herein was the significant enhancement of HIV-1 replication by low doses of 4 out of 41 lubricants. These include Astroglide lubricants, a very popular and commonly used brand. One common feature of three of these lubricants was the presence of a form of polyquaternium and we demonstrated that a related polyquaternium was able to enhance HIV replication in vitro
. Polyquaternium is the International Nomenclature for Cosmetic Ingredients designation for several polycationic polymers that are used in the personal care industry. It has been recognized that polycationic reagents can aid viral infection processes in vitro
by increasing viral attachment13–16
and reagents such as polybrene are widely utilized to increase the in vitro
infectivity of several retroviruses including HIV-1.20,21
None of the lubricants tested shows a potential for becoming a microbicide, thus we cannot advocate for any of these lubricants to be used as such based on our in vitro data. Additionally, many of the lubricants showed potential detrimental effects that might contribute to HIV transmission. This emphasizes the need for more rigorous testing of OTC personal lubricants as is typically applied to microbicides. It is also important to mention that our results are coming from in vitro studies and further studies looking at the effects of these lubricants in vivo, as well as more relevant studies correlating the use of these lubricants with the prevalence of STIs, are needed to clearly define the detrimental effects that lubricants may have on HIV and STI transmission.