Methylisothiazolinone

Methylisothiazolinone (MI) is an isothiazolinone-derived biocide.^1,2 It is active against Gram-positive and Gram-negative bacteria, as well as fungi, when used in combination with methylchloroisothiazolinone (MCI) with MIC values of 0.0002, 0.0002, 0.00005, and 0.00005% (w/w) for S. aureus, P. aeruginosa, A. niger, and C. albicans, respectively.² Methylisothiazolinone (50 µM) also inhibits c-Src autophosphorylation in a cell-free assay.³ It reduces cell viability percentage in isolated embryonic rat cortical neurons when used at a concentration of 3 µM and decreases neurite length at 1 µM. MI, alone and as a mixture with MCI, can elicit contact sensitization.⁴ Formulations containing methylisothiazolinone have been used in the control of bacteria, fungi, and algae in residential use and industry, as well as a preservative in personal care products.

WARNING This product is not for human or veterinary use.

1. Frenzel, E., Schmidt, S., Niederweis, M., et al. Importance of porins for biocide efficacy against Mycobacterium smegmatis. Appl. Environ. Microbiol. 77(9), 3068-3073 (2011).

2. Lundov, M.D., Johansen, J.D., Zachariae, C., et al. Low-level efficacy of cosmetic preservatives. Int. J. Cosmet. Sci. 33(2), 190-196 (2011).

3. He, K., Huang, J., Lagenaur, C.F., et al. Methylisothiazolinone, a neurotoxic biocide, disrupts the association of SRC family tyrosine kinases with focal adhesion kinase in developing cortical neurons. J. Pharmacol. Exp. Ther. 317(3), 1320-1329 (2006).

4. Scherrer, M.A.R., and Rocha, V.B. Increasing trend of sensitization to methylchloroisothiazolinone/methylisothiazolinone (MCI/MI). An. Bras. Dermatol. 89(3), 527-528 (2014).