Sodium benzoate and Methyl hydroxy benzoate (Methylparaben) are commonly used as preservative/antioxidant for pharmaceutical products such as syrups and multiple dose containers for liquid preparations. It is mainly effective in controlling molds, inhibiting yeast growth and protecting against bacterial proliferation. They can be used alone or in a combination in the assessment of synergistic effects (Mirsonbol et al., 2014; Boukarim et al., 2009).
Boukarim, C., Abou Jaoude, S., Bahnam, R., Barada, R., & Kyriacos, S. (2009). Preservatives in liquid pharmaceutical preparations. Drug Testing And Analysis, 1(3), 146-148. https://doi.org/10.1002/dta.28
Mirsonbol, S. Z., Issazadeh, K., Pahlaviani, M. R. M. K. & Momeni, N. (2014). Antimicrobial Efficacy of the Methylparaben and Benzoate Sodium against Selected Standard Microorganisms, Clinical and Environmental Isolates In Vitro. Indian Journal of Fundamental and Applied Life Sciences, 4(S4), 363-367.