Methylparaben concentration in commercial Brazilian local anesthetics solutions

Objective

To detect the presence and concentration of methylparaben in cartridges ofcommercial Brazilian local anesthetics.

Material and methods

Twelve commercial brands (4 in glass and 8 in plastic cartridges) of localanesthetic solutions for use in dentistry were purchased from the Brazilian marketand analyzed. Different lots of the commercial brands were obtained in differentBrazilian cities (Piracicaba, Campinas and São Paulo). Separation was performedusing high performance liquid chromatography (HPLC) with UV-Vis detector. Themobile phase used was acetonitrile:water (75:25 - v/v), pH 4.5, adjusted withacetic acid at a flow rate of 1.0 ml.min^-1.

Results

When detected in the solutions, the methylparaben concentration ranged from 0.01%(m/v) to 0.16% (m/v). One glass and all plastic cartridges presentedmethylparaben.

Conclusion

1. Methylparaben concentration varied among solutions from differentmanufacturers, and it was not indicated in the drug package inserts; 2. Since thepresence of methylparaben in dental anesthetics is not regulated by the BrazilianNational Health Surveillance Agency (ANVISA) and this substance could causeallergic reactions, it is important to alert dentists about its possiblepresence.