CYP (cytochrome P450); antifungal

Clotrimazole (brand names Canesten and Lotrimin) is an antifungal medication used to treat fungal diseases in humans and animals, including vaginal yeast infections, oral thrush, and ringworm. It is also used to relieve athlete's foot and jock itch. It is frequently available over the counter in a variety of dose forms, including creams and combo medications. It is also available as lozenges or lozenges (prescription required). Ear infections are typically treated with liquids such as ear drops. Clotrimazole, an antifungal medication, affects the action of gastric H,K-ATPase in the same way as Na,K-ATPase does. Because of its high hydrophobicity, clotrimazole interacts with the ion pump at the membrane domain in the membrane's nonpolar core. A half-saturating concentration of 5.2 microM reduces enzyme activity. Various pump cycle partial reactions were investigated using the electrochromic styrene-based dye RH421, which has been widely utilized to examine P-type ATPase transport mechanism.

In the treatment of vaginal candidiasis, clotrimazole vaginal tablets have produced cure rates comparable with those of conventional nystatin vaginal tablets. There have been no published comparisons with nystatin vaginal cream or foaming vaginal tablets - nystatin dosage forms preferred by some clinicians. Cootrimazole has also been successful in patients who had failed to respond to other antifungal agents such as nystatin and amphotericin B. Results in trichomonal vaginitis are not impressive. Skin infections caused by Candida or dermatophytes have been effectively treated with topical application of clotrimazole. In comparative trials, clotrimazole cream has been as effective as Whitfield's ointment and tolnaftate in the treatment of dermatophytoses, and as effective as nystatin in cutaneous candidiasis. Clotrimazole topical preparations are generally well tolerated, but local irritation has necessitated withdrawal of therapy in a few cases. Candidal septicemia and urinary and pulmonary candidiasis have been cured with oral clotrimazole therapy. Results in other types of serious fungal infections, including pulmonary aspergillosis, have been disappointing. A limiting factor in oral clotrimazole therapy is the high incidence of gastro-intestinal disturbances and neurological reactions[1].

Clotrimazole 2, a synthetic imidazole derivative, is primarily used locally in the treatment of vaginal and skin infections due to yeasts and dermatophytes. In vitro, it is most active against Candida spp., Trichophyton spp., Microsporum spp. and Malazzesia fuffur (Pityrosporon orbiculare). In addition, it has some in vitro activity against certain Gram-positive bacteria, and at very high concentrations has activity against Trichomonas spp.[1]

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The antimycotic drug clotrimazole inhibits the function of the gastric H,K-ATPase in a manner similar to that observed for the Na,K-ATPase. Because of the high hydrophobicity of the compound, the interaction between clotrimazole and the ion pump occurs at the membrane domain in the apolar core of the membrane. The enzymatic activity was inhibited with a half-saturating concentration of 5.2 microM. Various partial reactions of the pump cycle were analyzed with the electrochromic styryl dye RH421 that has been widely used to study the transport mechanism of P-type ATPases. We discovered that the interaction of clotrimazole with the H,K-ATPase introduces a single "dead-end" branch added to the Post-Albers scheme in the E(1) state of the pump. In this inhibiting state, the ion binding sites have a significantly enhanced affinity for protons and bind up to two protons even at pH 8.5. Inhibition of the pump can be reversed by a decreased pH or increased K(+) concentrations. The mechanistic proposal that allows an explanation of all experiments presented is similar to that published for the Na,K-ATPase[2].

Absorption, Distribution and Excretion
Because clotrimazole is generally not significantly absorbed, drug interactions are not a major issue with its use.
Mainly hepatic.
The topical form is minimally absorbed in the serum and tissues. Clotrimazole is a lipophilic drug, and has been shown to be secreted in breastmilk in animal studies. There are limited data available regarding the volume of distribution following oral troche administration.
GIVEN ORALLY OR IV WAS ABSORBED, DISTRIBUTED, ELIMINATED READILY. EXCRETED AS INACTIVE METABOLITE IN BILE, LITTLE IN URINE.
Absorption of clotrimazol is less than 0.5% after application to the intact skin: from the vagina, it is 3 to 10%. Fungicidal concentrations remain in the vagina for as long as 3 days after application of the drug. The small amount absorbed is metabolized in the liver and excreted in bile. In adults, an oral dose of 200 mg per day will give rise to plasma concentrations of 0.2 to 0.35 ug/ml.
Only very small amounts of clotrimazole appear to be absorbed systemically following topical application to the skin. Following application to the skin, highest concentrations of clotrimazole are present in the stratum corneum; lower drug concentrations occur in the stratum spinosum and the papillary and reticular dermis. Small amounts of clotrimazole are absorbed systemically when the drug is administered intravaginally. Following intravaginal administration of radiolabeled clotrimazole in patients with normal or inflamed vaginal mucosa, peak serum concentrations of clotrimazole 24 hours after insertion of a single 100 mg tablet of the drug are 0.03 ug/ml and peak serum concentrations 24 hours after administration of a cream containing 50 mg of the drug are 0.01 ug/ml. About 3-10% of an intravaginal dose of the drug reaches systemic circulation, principally as metabolites.
Clotrimazole is absorbed from the gastrointestinal tract ... and excreted in the feces and urine. When applied topically clotrimazole penetrates the epidermis but there is little if any systemic absorption. Slight absorption has been reported following the administration of vaginal tablets.

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Metabolism / Metabolites
Hepatic (metabolized to inactive metabolites).
Clotrimazole ... is metabolized in the liver to inactive compounds ... .
The effect of the antifungal imidazole compound, clotrimazole, on the metabolism of benzo[a]pyrene was studied in cultured keratinocytes prepared from BALB/c mouse epidermis. Varying concentrations of clotrimazole added to the cultured keratinocytes resulted in a dose dependent inhibition of the activities of the microsomal cytochrome p450 dependent monooxygenases aryl hydrocarbon hydroxylase and 7-ethoxycoumarin O-deethylase. The major organic solvent soluble metabolites of benzo(a)pyrene identified in the cultured cells were trans-7,8-dihydro-7,8-dihydroxybenzo(a)pyrene, 9-hydroxybenzo(a)pyrene, and 3-hydroxybenzo(a)pyrene, although small amounts of trans-4,5-dihydro-4,5-dihydroxybenzo(a)pyrene, benzo(a)pyrene-quinones, and trans-9,10-dihydroxybenzo(a)pyrene were also present. The major organic solvent extractable metabolites of benzo(a)pyrene found in the extracellular culture medium were primarily the diols with smaller quantities of phenols and quinones. The major water soluble metabolites of benzo(a)pyrene present both intracellularly and extracellularly were glucuronide conjugates of 3-hydroxybenzo(a)pyrene, 9-hydroxybenzo(a)pyrene, and benzo(a)pyrene-3,6-dione and to a lesser extent sulfate conjugates (primarily of the trans-7,8-dihydro-7,8- dihydroxybenzo(a)pyrene). Clotrimazole inhibited the generation of organic solvent soluble and water soluble conjugates in a dose dependent manner. The in vitro metabolism of benzo(a)pyrene by microsomes prepared from control and benz(a)anthracene induced cultured keratinocytes was also inhibited by clotrimazole with greater inhibitory effect on benz(a)anthracene induced keratinocytes especially with respect to the formation of diols and quinones. The enzyme mediated covalent binding of benzo(a)pyrene to mouse keratinocyte DNA and protein was also substantially diminished by clotrimazole in a dose dependent fashion. These results indicate that clotrimazole, a widely used drug for the management of a variety of superficial dermatophyte infections of the skin, is a potent inhibitor of cytochrome p450 dependent transformation of polycyclic aromatic hydrocarbons in cultured murine keratinocytes. This system offers a convenient approach for studies as inhibitors of carcinogen metabolism in the epidermis.
Hepatic (metabolized to inactive metabolites)
Half Life: 2 hours

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Biological Half-Life
Clotrimazole was given by mouth in a dose of 1.5 g to 7 healthy subjects and 47 patients and peak blood concentrations of up to 1 ug/ml were detected microbiologically at 2 or 4 hours. The half-life was between 3.5 and 5.5 hours.
Clotrimazole was absorbed from the gastrointestinal tract and had a biological half-life of about 4 hours. Liver and kidney dysfunction had little influence on serum concentrations or half-life.

Toxicity Summary
Clotrimazole interacts with yeast 14-α demethylase, a cytochrome P-450 enzyme that converts lanosterol to ergosterol, an essential component of the membrane. In this way, clotrimazole inhibits ergosterol synthesis, resulting in increased cellular permeability. Clotrimazole may also inhibit endogenous respiration, interact with membrane phospholipids, inhibit the transformation of yeasts to mycelial forms and the uptake of purine, impair triglyceride and/or phospholipid biosynthesis, and inhibit the movement of calcium and potassium ions across the cell membrane by blocking the ion transport pathway known as the Gardos channel.

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Interactions
A synergistic effect of clotrimazole and certain anionic surfactants against a strain of Candida albicans was confirmed. Measurement of apparent partition coefficients indicated that lipophilic ion pairs between clotrimazole and anionic surfactants were formed. It is suggested that the synergistic effect of the drugs may be due to ion pair formation.

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Non-Human Toxicity Values
LD50 Rat, male oral 708 mg/kg
LD50 Mouse, male oral 923 mg/kg

[1]. Sawyer PR, Clotrimazole: a review of its antifungal activity and therapeutic efficacy. Drugs. 1975;9(6):424-47.

[2]. Witzke A, Inhibition of the gastric H,K-ATPase by clotrimazole. Biochemistry. 2010 Jun 1;49(21):4524-32.

[3]. Schaller K. In vitro antibacterial activity of different clotrimazole formulations. Chemotherapy. 1982;28 Suppl 1:32-6.

Therapeutic Uses
Anti-Infective Agents, Local; Antifungal Agents; Growth Inhibitors
CLOTRIMAZOLE IS A CHLORINATED IMIDAZOLE DERIVATIVE THAT IS USED TO TREAT TOPICAL FUNGAL, DERMATOPHYTE, & YEAST INFECTIONS. WHILE CLOTRIMAZOLE HAS MARKED IN VITRO ACTIVITY AGAINST MANY FUNGI, IT IS OF LITTLE VALUE IN TREATMENT OF SYSTEMIC MYCOSES.
VAGINAL: 1 TABLET (100 MG) IS INSERTED DAILY FOR 1 WK FOR CANDIDAL VAGINITIS. TOPICAL: SUFFICIENT CREAM OR SOLN IS APPLIED TWICE DAILY TO SKIN INFECTED WITH CANDIDA ALBICANS, TRICOPHYTON, OR MICROSPORUM SPECIES. 2 WK OF THERAPY IS USUALLY SUFFICIENT.
CLOTRIMAZOLE HAS BEEN USED INVESTIGATIONALLY FOR ORAL TREATMENT OF MUCOCUTANEOUS CANDIDIASIS.
For more Therapeutic Uses (Complete) data for CLOTRIMAZOLE (12 total), please visit the HSDB record page.

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Drug Warnings
PREPN OF CLOTRIMAZOLE ARE NOT INTENDED FOR OPHTHALMIC USE & SHOULD BE USED WITH CAUTION AROUND EYES.
Clotrimazole lozenges should not be used for the treatment of systemic myotic infections.
Clotrimazole Vaginal tablets ... single-dose therapy is not recommended for the treatment of severe vulvovaginal candidiasis.
To achieve maximum theraputic effect of clotrimazole when the drug is administered orally as a lozenge, the lozenge must be dissolved slowly in the mouth. Therefore, patients receiving clotrimazole lozenges must be of such age and physical and/or mental condition that they can comprehend and follow administration instruction. Liver function tests should be conducted periodically during oral therapy with clotrimazole lozenges, especially in patients with preexisting hepatic impairment.
Clotrimazole topical cream, lotion, and solution should be used during the first trimester of pregnancy only when the drug is considered essential to the welfare of the patient. Since it is not known whether clotrimazole is distributed into milk, the drug should be used with caution in nursing women.

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Pharmacodynamics
Clotrimazole is a broad-spectrum antifungal agent that inhibits the growth of pathogenic yeasts by changing the permeability of cell membranes. The action of clotrimazole is fungistatic at concentrations of drug up to 20 mcg/mL and may be fungicidal _in vitro_ against Candida albicans and other species of the genus Candida at higher concentrations. Unfortunately, resistance to clotrimazole, which was rare in the past, is now common in various patient populations. Clotrimazole is generally considered to be a fungistatic, and not a fungicidal drug, although this contrast is not absolute, as clotrimazole shows fungicidal properties at higher concentrations.

C22H17CLN2

344.84

344.108

C, 76.63; H, 4.97; Cl, 10.28; N, 8.12

23593-75-1

Clotrimazole-d5;1185076-41-8

2812

White to off-white solid powder

1.1±0.1 g/cm3

482.3±40.0 °C at 760 mmHg

147-149ºC

245.5±27.3 °C

0.0±1.2 mmHg at 25°C

1.617

5.44

0

1

4

25

396

0

VNFPBHJOKIVQEB-UHFFFAOYSA-N

InChI=1S/C22H17ClN2/c23-21-14-8-7-13-20(21)22(25-16-15-24-17-25,18-9-3-1-4-10-18)19-11-5-2-6-12-19/h1-17H

1-[(2-chlorophenyl)-diphenylmethyl]imidazole

Canesten; Lotrimin; 23593-75-1; Lotrimin; Canesten; Mycelex; Mycosporin; Clotrimazol; Empecid; Clotrimazole

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

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

DMSO : ~50 mg/mL (~144.99 mM)
H2O : ~0.1 mg/mL (~0.29 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (7.25 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.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (7.25 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.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (7.25 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.

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