Subchronic (26‐ and 52‐week) toxicity and irritation studies of a novel microbicidal gel formulation containing sodium lauryl sulfate in animal models

Abstract

The safety of an ethylene oxide/propylene oxide gel formulation containing sodium lauryl sulfate (2%, w/w), that could be a potent candidate as a topical microbicide, has been evaluated. More specifically, the subchronic (26- and 52-week) toxicity of the formulation when applied intravaginally as well as its irritating potential for the rectal, penile, eye, skin and buccal mucosa have been examined in animal models. The results showed that the vaginal administration of the gel formulation containing sodium lauryl sulfate once and twice daily (with doses 12 +/- 2 h apart) for 26 weeks to rats and for 52 weeks to rabbits induced slight to moderate histopathological alterations. When the formulation was applied intrarectally to male and female rabbits once and twice daily (with doses 12 +/- 2 h apart) for 14 days, no macroscopic or microscopic changes were reported. For both vaginal and rectal dosing, no effect was seen on the haematology, coagulation and serum chemistry parameters as well as on the body weight of animals and the relative organ weights. Other sporadic macroscopic and histopathological findings were incidental in origin and of no toxicological significance. The gel formulation containing sodium lauryl sulfate was considered as mildly irritating for the penile mucosa of rabbits, non-irritating for the eye of rabbits, mildly irritating for the skin in a rabbit model and non-irritating for the hamster cheek pouch. It is suggested that the gel formulation containing sodium lauryl sulfate is safe for most tissues that could be exposed to the product under normal use.

Human and Environmental Toxicity of Sodium Lauryl Sulfate (SLS): Evidence for Safe Use in Household Cleaning Products

“…24,25 Human patch tests (typically a 24-hour exposure) confirm that SLS concentrations ≫2% are considered irritating to normal skin. 2,26,27 Dermal irritation also tends to increase with SLS concentration and the duration of direct contact. 2 In reality, dermal exposure to SLS in cleaning products is more likely to last a matter of minutes rather than hours.…”

A simple method for oral mucosal irritation test by intraoral instillation in rats

“…So, non-clinical local tolerance testing of gargle products is necessary to investigate the oral mucosal irritation potential. The evaluation of oral mucosal irritation has been widely conducted by methods such as contacting and swabbing of the test substances on the mucosa of cheek pouch in hamsters (Namiki et al, 1998;Anand et al, 2003;Piret et al, 2008). Other animals such as rats (Nakamura and Masuda, 1994;Arvidsson et al, 2001), guinea pigs (Nakamura and Masuda, 1994;Manabe et al, 2001), dogs (Nixon et al, 1972) and rabbits (Müller et al, 1983) have also been used for the evaluation of oral mucosal irritation.…”