Fungal cytochrome P450 51 (CYP51, 14α-demethylase, key enzyme in ergosterol synthesis):
- Inhibition of Candida albicans CYP51: MIC (Minimum Inhibitory Concentration) ≈ 0.125–0.5 μg/mL [1];
- Inhibition of Trichophyton rubrum CYP51: MIC ≈ 0.06–0.25 μg/mL [1];
- Inhibition of Microsporum canis CYP51: MIC ≈ 0.25–1 μg/mL [3]

Econazole nitrate is an effective inducer of micronuclei over a narrow dose range in cell lines V79, XEM2 and XEMd-MZ (expresses CYP1A2). Econazole nitrate inhibits the proliferation of MCF-7 cells in a time- and dose-dependent manner by MTT method and colony forming assay. Econazole nitrate results in typical characteristics of apoptosis including the morphological changes and DNA fragmentation in MCF-7 cells. Econazole nitrate results in the decrease expression of procaspase-3, procaspase-9 and bcl-2. Econazole inhibits ADP-ribose-activated currents in HEK-293 cells expressing recombinant human TRPM2 (hTRPM2). Econazole produces an essentially complete inhibition of the TRPM2-mediated current. Econazole (25-50 mM) partially inhibits capacitative Ca2+ entry induced by cyclopiazonic acid, another endoplasmic reticulum Ca2+ pump inhibitor. Econazole induces Ca2+ influx via two separate pathways: one is sensitive to La3+, the other is not. Econazole reversibly inhibits (Bu)(2)cAMP-stimulated progesterone production in a dose- and time-dependent manner in MA-10 cells without affecting total protein synthesis or P450(scc) and 3beta-hydroxysteroid dehydrogenase (3beta-HSD) enzyme expression or activity. Econazole is a store-operated Ca2+ channel antagonist which induces cytotoxic cell death of leukemia. Econazole (5-20 mM) arrests human colon cancer cells at the G0/G1 phase of the cell cycle. Econazole induces COLO 205 cells apoptosis evidenced by ladder formation in DNA fragmentation assay and sub-G1 peak.

---

Antifungal activity (literature [1], [2], [3]):
1. Yeast fungi (Candida spp.):
- Econazole nitrate (0.03–8 μg/mL, broth microdilution assay) inhibited C. albicans (MIC₈₀ ≈ 0.125 μg/mL), C. glabrata (MIC₈₀ ≈ 0.5 μg/mL), and C. tropicalis (MIC₈₀ ≈ 0.25 μg/mL). At 1 μg/mL, C. albicans growth was reduced by ~90% vs. control [1]
2. Dermatophytes (filamentous fungi):
- T. rubrum (causative agent of tinea corporis): MIC₈₀ ≈ 0.06 μg/mL (agar diffusion assay); 0.5 μg/mL inhibited spore germination by ~95% [1];
- T. mentagrophytes (tinea pedis): MIC₈₀ ≈ 0.125 μg/mL [3];
- M. canis (tinea capitis): MIC₈₀ ≈ 0.25 μg/mL [3]
3. Other pathogenic fungi:
- Malassezia furfur (pityriasis versicolor): MIC₈₀ ≈ 0.5 μg/mL (broth dilution assay) [2]
- Fungal cell membrane disruption:
1. C. albicans treated with 0.5 μg/mL Econazole nitrate for 24 hours: Ergosterol content reduced by ~70% (HPLC analysis); membrane permeability increased by ~40% (fluorescein diacetate staining, flow cytometry). Cells showed swelling and irregular morphology (light microscopy) [1]

Guinea pig dermatophytosis model (T. mentagrophytes-induced tinea corporis, literature [3]):
1. Grouping: Guinea pigs (n=6/group) randomized into 3 groups: (1) Untreated control; (2) Vehicle control (topical cream base); (3) Econazole nitrate 1% topical cream [3]
2. Treatment: Back skin depilated, inoculated with 1×10⁶ CFU/mL T. mentagrophytes spore suspension. Topical administration started 24 hours post-inoculation, once daily for 14 days (0.1 g cream/cm² infected area) [3]
3. Efficacy:
- Lesion score (erythema, scaling, pruritus): Reduced by ~80% in drug group vs. vehicle control at day 14;
- Fungal clearance: 100% of drug-treated animals had negative fungal cultures (skin scrapings plated on Sabouraud agar) vs. 0% in control groups [3]
- Mouse cutaneous candidiasis model (C. albicans-induced skin infection, literature [1]):
1. Treatment: Econazole nitrate 0.5% topical solution applied to infected dorsal skin (0.05 mL/cm²) once daily for 7 days [1]
2. Efficacy: Skin fungal load (CFU/g tissue) reduced by ~99% vs. vehicle control at day 7; histopathology showed no residual fungal hyphae [1]

Fungal CYP51 activity inhibition assay:
1. Protein preparation: Recombinant C. albicans CYP51 expressed in Saccharomyces cerevisiae, purified via nickel-chelate chromatography, resuspended in assay buffer (50 mM Tris-HCl, pH 7.4, 1 mM EDTA, 0.1 mM DTT) [1]
2. Reaction setup: 200 μL mixture contained purified CYP51 (0.5 μg), substrate lanosterol (10 μM), NADPH (1 mM), and Econazole nitrate (0.01–10 μg/mL). Vehicle (DMSO) used as control [1]
3. Incubation and detection: Incubated at 37°C for 60 minutes; reaction stopped with 50 μL methanol. Product (14α-demethyl lanosterol) quantified via HPLC (UV detection at 280 nm). Inhibition rate = (1 – product of drug group / product of control group) × 100% [1]
4. Data analysis: IC₅₀ for CYP51 inhibition calculated as ~0.08 μg/mL via four-parameter logistic fitting [1]

Fungal broth microdilution susceptibility assay (literature [1], [2]):
1. Fungal preparation: C. albicans/T. rubrum cultured in Sabouraud dextrose broth (SDB) to log phase, adjusted to 1×10⁴ CFU/mL (yeast) or 1×10³ CFU/mL (dermatophytes) [1][2]
2. Drug treatment: Econazole nitrate serially diluted (0.03–8 μg/mL) in 96-well plates, mixed with fungal suspension (1:1 volume). Incubated at 35°C for 48 hours (yeast) or 72 hours (dermatophytes) [1][2]
3. Growth detection: Yeast growth measured via absorbance at 600 nm; dermatophyte growth assessed by visual inspection. MIC₈₀ defined as the lowest concentration inhibiting 80% growth [1][2]
- Fungal cell membrane permeability assay:
1. Cell treatment: C. albicans (1×10⁶ cells/mL) treated with Econazole nitrate (0.125–2 μg/mL) for 24 hours [1]
2. Staining: Cells stained with fluorescein diacetate (FDA, 5 μg/mL) for 30 minutes at 37°C. FDA enters intact cells and converts to fluorescent fluorescein; membrane damage reduces fluorescence [1]
3. Analysis: Fluorescence intensity measured via flow cytometry; permeability increase calculated as (1 – fluorescence of drug group / fluorescence of control group) × 100% [1]

Guinea pig T. mentagrophytes infection protocol:
1. Animal housing: Female guinea pigs (250–300 g) housed in standard facilities (22–24°C, 12-hour light/dark cycle) with free access to food and water [3]
2. Infection induction: Dorsal skin depilated (2×2 cm area) with depilatory cream. Inoculated with 100 μL of 1×10⁶ CFU/mL T. mentagrophytes spore suspension (in 0.9% saline), covered with sterile gauze for 24 hours to maintain moisture [3]
3. Grouping and treatment: 24 hours post-inoculation, animals randomized to 3 groups. Econazole nitrate 1% cream prepared in oil-in-water base; applied topically (0.1 g/cm²) once daily for 14 days. Vehicle group received cream base alone; untreated group no intervention [3]
4. Monitoring and analysis: Lesion score (0–4 scale: 0=normal, 4=severe erythema/scaling) recorded every 3 days. On day 14, skin scrapings collected, plated on Sabouraud agar (35°C, 7 days) for fungal culture. Skin tissue fixed in 10% formalin for histopathology (PAS staining to detect fungal hyphae) [3]

Local skin absorption (References [3], [4]):
1. Human skin absorption: Healthy volunteers (n=5) applied 1% econazole nitrate cream to their forearms (10 cm² area, 0.1 g/cm²). 24 hours after application:
- Stratum corneum concentration: ~5–10 μg/g;
- Dermal layer concentration: ~0.1–0.3 μg/g;
- Plasma concentration: <0.01 μg/mL (not detectable by HPLC)[4]
2. Guinea pig skin absorption: similar to that in humans; 24 hours after topical application of 1% cream, plasma concentration <0.005 μg/mL [3]
- Oral pharmacokinetics:
1. Oral bioavailability: <5% (rat, 10 mg/kg oral dose compared with intravenous dose); most of the drug is not absorbed in the gastrointestinal tract[1]
2. Half-life: Topical application: local skin half-life is about 8–12 hours (guinea pig)[3]; Oral administration: terminal half-life is about 2.5 hours (rat)[1]

In vitro toxicity:
1. Human keratinocytes (HaCaT cells):Econazole nitrate (0.1–20 μg/mL, 24-hour treatment) showed no obvious cytotoxicity; cell viability was >90% at 10 μg/mL (MTT method)[4]
2. Human fibroblasts: 20 μg/mLEconazole nitrate reduced cell viability by <10% (LDH release assay)[4]
- In vivo toxicity (References [3], [4]):
1. Acute oral toxicity:
- Single oral LD₅₀ ≈ 1600 mg/kg in mice;
- Single oral LD₅₀ ≈ 2000 mg/kg in rats;
- Overdose symptoms: transient diarrhea and drowsiness, relieved within 48 hours[3]
2. Local skin toxicity:
- Guinea pig closed patch test (1% cream, 24 hours): no erythema or edema; primary irritation index (PII) <0.5 (classified as “non-irritating”)[4]; - Rabbit eye irritation test: no corneal opacity or conjunctival hyperemia (1% solution, single eye drop)[3] - Plasma protein binding rate: ~95% (human plasma, 37°C balanced dialysis)[1]

[1]. Eur J Pharmacol.2006 Feb 15;531(1-3):1-8

[2]. Iran J Pharm Res.2014 Fall;13(4):1327-34.

[3]. Arzneimittelforschung, 1975. 25(2): p. 224-30.

[4]. J Am Acad Dermatol. 1990 Apr;22(4):583-6.

Econazole nitrate is a white crystalline powder. (NTP, 1992)
Econazole nitrate is an imidazole derivative with antifungal activity and is a broad-spectrum antifungal agent. Econazole nitrate inhibits the biosynthesis of ergosterol, thereby disrupting the fungal cell wall membrane and altering its permeability, leading to the loss of essential intracellular components. Furthermore, econazole nitrate inhibits the biosynthesis of triglycerides and phospholipids, and inhibits the activity of oxidases and peroxidases, which may lead to cell necrosis and cell death. Econazole nitrate is also effective against certain Gram-positive bacteria. This antifungal agent is used to treat various fungal dermatophytes.
A commonly used topical antifungal agent.
See also: Econazole (containing the active ingredient); Econazole nitrate; Nicotinamide (ingredient)... See more...
Background:Econazole nitrate is an imidazole antifungal drug used for the topical treatment of superficial fungal infections. It targets fungal CYP51, which is a key enzyme in the synthesis of ergosterol (an essential component of the fungal cell membrane) [1][3]
-Mechanism of action: inhibiting fungal CYP51 and blocking the 14α-demethylation of lanosterol (a precursor of ergosterol). This leads to a reduction in ergosterol in the fungal cell membrane, accumulation of toxic methylated sterols, damage to the structure/function of the cell membrane, and ultimately fungal cell death [1][3]
- Treatment indications: Topical treatment of dermatophytes (tinea corporis, tinea cruris, tinea pedis, tinea capitis), candidiasis (cutaneous candidiasis, vulvovaginal candidiasis, preputial candidiasis) and tinea versicolor [4]
- FDA status: Approved for use in humans as a topical antifungal agent (e.g., Spectazole® 1% cream); for superficial fungal infections [4]
- Precautions: Avoid contact with eyes and mucous membranes; discontinue use if allergic reaction (rash, itching) occurs; do not use systemically [4]

C18H15CL3N2O.HNO3

444.7

443.02

C, 48.62; H, 3.63; Cl, 23.92; N, 9.45; O, 14.39

24169-02-6

Econazole;27220-47-9

68589

White to off-white solid powder.

162°C

5.976

1

5

6

28

404

0

ClC1C([H])=C(C([H])=C([H])C=1C([H])(C([H])([H])N1C([H])=NC([H])=C1[H])OC([H])([H])C1C([H])=C([H])C(=C([H])C=1[H])Cl)Cl.O([H])[N+](=O)[O-]

DDXORDQKGIZAME-UHFFFAOYSA-N

InChI=1S/C18H15Cl3N2O.HNO3/c19-14-3-1-13(2-4-14)11-24-18(10-23-8-7-22-12-23)16-6-5-15(20)9-17(16)21;2-1(3)4/h1-9,12,18H,10-11H2;(H,2,3,4)

1-[2-[(4-chlorophenyl)methoxy]-2-(2,4-dichlorophenyl)ethyl]imidazole;nitric acid

Econazole Nitrate; R 14,827; R 14827; Spectazole; SQ 13050; SQ13050; SQ-13050; Ecoza; epi-Pevaryl; Gyno-pevaryl; Ifenec.

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : 50~89 mg/mL ( 112.44~200.13 mM )
H2O : 0.67 mg/mL (1.51 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (5.62 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

---

Solubility in Formulation 2: ≥ 2.5 mg/mL (5.62 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

---

View More

Solubility in Formulation 3: ≥ 2.5 mg/mL (5.62 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

---

Solubility in Formulation 4: 10% DMSO+40% PEG300+5% Tween-80+45% Saline: ≥ 2.5 mg/mL (5.62 mM)

---

 (Please use freshly prepared in vivo formulations for optimal results.)