Efinaconazole-d4 is intended for use as an internal standard for the quantification of efinaconazole by GC- or LC-MS. Efinaconazole is a broad-spectrum triazole antifungal agent with activity against Acremonium, Aspergillus, Candida, Cryptococcus, Epidermophyton, Fusarium, Microsporum, Paecilomyces, Pseudallescheria, Scopulariopsis, Trichophyton, and Trichosporon.1 It inhibits the growth of T. rubrum and T. mentagrophytes clinical isolates with MIC values ranging from ≤2.0 to 60 ng/ml and of C. albicans isolates with MIC values ranging from ≤0.5 to >250 ng/ml. Efinaconazole inhibits sterol 14α-demethylase, which arrests ergosterol biosynthesis at the fungal membrane.2 It inhibits ergosterol biosynthesis in T. mentagrophytes and C. albicans with IC50 values of 7.0 and 0.40 ng/ml, respectfully. Topical formulations containing efinaconazole have been used for the treatment of onychomycosis.
1.Jo Siu, W.J., Tatsumi, Y., Senda, H., et al.Comparison of in vitro antifungal activities of efinaconazole and currently available antifungal agents against a variety of pathogenic fungi associated with onychomycosisAntimicrob. Agents Chemother.57(4)1610-1616(2013) 2.Tatsumi, Y., Nagashima, M., Shibanushi, T., et al.Mechanism of action of efinaconazole, a novel triazole antifungal agentAntimicrob. Agents Chemother.57(5)2405-2409(2013)