Naftin (Naftifine Hydrochloride) - Description and Clinical Pharmacology

Rx Only

DESCRIPTION

Naftin^® Cream, 1% contains the synthetic, broad-spectrum, antifungal agent naftifine hydrochloride. Naftin^® Cream, 1% is for topical use only.

Chemical Name

(E)-N-Cinnamyl-N-methyl-1-naphthalenemethylamine hydrochloride. Naftifine hydrochloride has an empirical formula of C₂₁H₂₁N•HCl and a molecular weight of 323.86.

CLINICAL PHARMACOLOGY

Naftifine hydrochloride is a synthetic allylamine derivative. The following in vitro data are available, but their clinical significance is unknown. Naftifine hydrochloride has been shown to exhibit fungicidal activity in vitro against a broad spectrum of organisms, including Trichophyton rubrum, Trichophyton mentagrophytes, Trichophyton tonsurans, Epidermophyton floccosum, Microsporum canis, Microsporum audouini, and Microsporum gypseum; and fungistatic activity against Candida species, including Candida albicans. Naftin^® Cream, 1% has only been shown to be clinically effective against the disease entities listed in the INDICATIONS AND USAGE section.

Although the exact mechanism of action against fungi is not known, naftifine hydrochloride appears to interfere with sterol biosynthesis by inhibiting the enzyme squalene 2, 3-epoxidase. This inhibition of enzyme activity results in decreased amounts of sterols, especially ergosterol, and a corresponding accumulation of squalene in the cells.

Pharmacokinetics

In vitro and in vivo bioavailability studies have demonstrated that naftifine penetrates the stratum corneum in sufficient concentration to inhibit the growth of dermatophytes.

Following a single topical application of 1% naftifine cream to the skin of healthy subjects, systemic absorption of naftifine was approximately 6% of the applied dose. Naftifine and/or its metabolites are excreted via the urine and feces with a half-life of approximately two to three days.