Reversed-phase high-performance liquid chromatography versus spectrophotometric assay for thimerosal in Cuban recombinant hepatitis B vaccine☆

A reversed-phase liquid chromatographic method was applied to study the stability of thimerosal in Cuban recombinant hepatitis B vaccine samples stored under different temperature conditions. Salicylic acid was used as internal standard, it allowed one to determine the thimerosal in the presence of its degradation products. Good stability of the preservative was demonstrated in vaccine samples for as long as 6 years. The same results were obtained when the vaccine samples were incubated at 37 and 45°C during 30 days. The results were in compliance with the microbiological test for determining the effectiveness of antimicrobial preservative in these samples.