Sensitive and selective LC-MS/MS assay for quantitation of flutrimazole in human plasma

OBJECTIVE

A highly sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of flutrimazole in human plasma. This study was to investigate the application of sensitive and selective LC-MS/MS method for quantitation of flutrimazole in human plasma.

MATERIALS AND METHODS

The analysis and internal standard were extracted with ether and hexane (v:v, 1:1) followed by a rapid isocratic elution with a 0.1% formic acid/methanol (v:v, 20:80) on a C18 column (50 mm × 2.1 mm I.D.) and subsequent analysis by mass spectrometry in the multi-reaction-monitoring mode. The precursor to production transitions of m/z 279.0 → 183.1 and m/z 441.0 → 295.1 were used to measure the analyte and the internal standard.

RESULTS

The assay was linear over the concentration range of 0.996-99.6 ng•mL-1 for flutrimazole in human plasma. The lower limit of quantification was 0.996 ng•mL-1 and the extraction recovery was larger than 78.83% for flutrimazole. The inter- and intra-day precision of the method at three concentrations was less than 9.26%.

CONCLUSIONS

The LC-MS/MS method was firstly applied to quantitation of flutrimazole in human plasma.

Flutrimazole shampoo 1% versus ketoconazole shampoo 2% in the treatment of pityriasis versicolor. A randomised double-blind comparative trial

Flutrimazole is an imidazole derivative that has been proven to be efficient in superficial skin fungal infections. The aim of this randomised double-blind study was to compare for the first time, the efficiency and safety of flutrimazole 1% shampoo versus ketoconazole 2% shampoo in the treatment of tinea versicolor. Study population consisted of 60 patients with pityriasis versicolor diagnosed clinically and through direct microscopy and culture. Patients were randomly assigned to two groups: one instructed to apply flutrimazole shampoo 1% and one instructed to apply ketoconazole shampoo 2% both on head and body for 14 days. Patients were re-evaluated 14 days after the end of treatment clinically and through direct microscopy and culture. Twenty-one of 26 patients (80.8%) in the ketoconazole and 22 of 29 patients (75.9%) in the flutrimazole group had both visual healing and negative mycological evaluation. Comparison of the response between the two groups with the Yates' corrected chi-square was found statistically not significant (chi(2) = 0.19, d.f. = 1, P = 0.91). None of the patients in the two groups reported any adverse effects. Fourteen (53%) patients in the ketoconazole group and 23 (79%) in the flutrimazole group assessed the shampoos as cosmetically acceptable regarding texture, smell and foam properties. Flutrimazole shampoo 1% appears to present efficacy comparable with ketoconazole 2% in the treatment of tinea versicolor.

Design and synthesis of potent antimalarial agents based on clotrimazole scaffold: exploring an innovative pharmacophore

Identification of new molecular scaffolds structurally unrelated to known antimalarials may represent a valid strategy to overcome resistance of P. falciparum (Pf) to currently available drugs. We describe herein the investigation of a new polycyclic pharmacophore, related to clotrimazole, to develop innovative antimalarial agents. This study allowed us to discover compounds characterized by a high in vitro potency, particularly against Pf CQ-resistant strains selectively targeting free heme, which are easy to synthesize by low-cost synthetic strategies.

Genetic neural network modeling of the selective inhibition of the intermediate-conductance Ca2+-activated K+ channel by some triarylmethanes using topological charge indexes descriptors

Selective inhibition of the intermediate-conductance Ca(2+)-activated K(+ )channel (IK (Ca)) by some clotrimazole analogs has been successfully modeled using topological charge indexes (TCI) and genetic neural networks (GNNs). A neural network monitoring scheme evidenced a highly non-linear dependence between the IK (Ca) blocking activity and TCI descriptors. Suitable subsets of descriptors were selected by means of genetic algorithm. Bayesian regularization was implemented in the network training function with the aim of assuring good generalization qualities to the predictors. GNNs were able to yield a reliable predictor that explained about 97% data variance with good predictive ability. On the contrary, the best multivariate linear equation with descriptors selected by linear genetic search, only explained about 60%. In spite of when using the descriptors from the linear equations to train neural networks yielded higher fitted models, such networks were very unstable and had relative low predictive ability. However, the best GNN BRANN 2 had a Q ( 2 ) of LOO of cross-validation equal to 0.901 and at the same time exhibited outstanding stability when calculating 80 randomly constructed training/test sets partitions. Our model suggested that structural fragments of size three and seven have relevant influence on the inhibitory potency of the studied IK (Ca) channel blockers. Furthermore, inhibitors were well distributed regarding its activity levels in a Kohonen self-organizing map (KSOM) built using the inputs of the best neural network predictor.

The role of hydrogen bond acceptor groups in the interaction of substrates with Pdr5p, a major yeast drug transporter

The yeast ABC (ATP-binding cassette protein) multidrug transporter Pdr5p transports a broad spectrum of xenobiotic compounds, including antifungal and antitumor agents. Previously, we demonstrated that substrate size is an important factor in substrate-transporter interaction and that Pdr5p has at least three substrate-binding sites. In this study, we use a combination of whole cell transport assays and photoaffinity labeling of Pdr5p with [(125)I]iodoarylazidoprazosin in purified plasma membrane vesicles to study the behavior of two series of novel substrates: trityl (triphenylmethyl) and carbazole derivatives. The results indicate that site 2, defined initially by tritylimidazole efflux, requires at least a single hydrogen bond acceptor group (electron pair donor). In contrast, complete inhibition of rhodamine 6G efflux and [(125)I]iodoarylazidoprazosin binding at site 1 requires substrates with three electronegative groups. Carbazole and trityl substrates with two groups show saturating, incomplete inhibition at this site. This type of inhibition is frequently observed in bacterial multidrug-binding proteins that use a pocket with multiple binding sites. The presence of multiple sites with different requirements for substrate-Pdr5p interaction may explain the broad specificity of xenobiotic compounds transported by this protein.

Triaryl methane derivatives as antiproliferative agents

Clotrimazole (CLT) 1, a synthetic anti-fungal imidazole derivative, inhibits tumor cell proliferation and angiogenesis. In the current study, flow cytometric analysis demonstrated that the decrease in tumor cell growth by CLT 1 was associated with inhibition of cell cycle progression at the G(1)-S phase transition, resulting in G(0)-G(1) arrest. A series of CLT 1 analogues has been generated in order to develop CLT 1 derivatives that are devoid of the imidazole moiety which is responsible for the hepatoxicity associated with CLT 1 while retaining CLT 1 efficacy. The majority of these analogues demonstrate in vitro antiproliferative activity ranging from submicromolar to micromolar concentrations.

In vitro activities of transition metal derivatives of ketoconazole and clotrimazole against a wild type strain of Saccharomyces cerevisiae in absence or presence of human neutrophils

In vitro activities of a series of gold, copper and ruthenium clotrimazole (CTZ, CAS 23593-75-1) and ketoconazole (KTZ, CAS 65277-42-1) derivatives were investigated individually and in combination with human neutrophils (PMNs) against a wild type strain of Saccharomyces cerevisiae. For 11 out of 12 tested metal complexes, the minimal inhibitory concentrations (MICs) at which 100 % of yeast growth was inhibited ranged from 0.75 to 3.0 micromol/L. The complex RuCl3(CTZ)3 x 2CH3OH (1f) (MIC = 0.75 micromol/L) was, although modestly, the only one able to increase the fungistatic activity of the parental drug (MIC = 1 micromol/L). On the other hand, at a sub-MIC concentration (0.5 micromol/L), the complexes [Cu(KTZ)Cl2]2 x 2H2O (2c) and RuCl2(KTZ)2 (2e) displayed synergistic fungicidal effects with PMNs whereas phagocytic capacity was enhanced by complexes [Cu(KTZ)3Cl2] (2b) and RuCl2(KTZ)2 (2e). The findings suggest that the metal-based agents may give rise to drugs with improved antifungal properties.

NC381, a Novel Anticancer Agent, Arrests the Cell Cycle in G0-G1 and Inhibits Lung Tumor Cell Growth in Vitro and in Vivo

Although clotrimazole (CLT), an antifungal drug, inhibits tumor cell proliferation and angiogenesis, its clinical application is hampered by significant hepatotoxicity due to the presence of an imidazole moiety. In our attempts to develop CLT analogs that are devoid of imidazole and are as efficacious as CLT, one pharmacophore designated NC381 was generated and shown to inhibit tumor cell growth via a mechanism similar to that of CLT. In vitro, treatment of NCI-H460 nonsmall cell lung cancer (NSCLC) cells with NC381 inhibited growth in a time-dependent manner. Flow cytometric analysis demonstrated that the decrease in cell growth was associated with inhibition of cell cycle progression at the G(1)-S phase transition, resulting in G(0)-G(1) arrest. There was a concomitant inhibition of cyclin D1 expression and subsequent reduction in the formation of the cyclin D1-CDK4 complex. Consistent with a decrease in the cyclin D1-CDK4 complex, NC381 treatment resulted in significant inhibition of pRb phosphorylation. There also were changes in the activity of cell cycle-related proteins, including p16(Ink4) and p27(Kip1). Together, these results are consistent with a model in which NC381 arrests cell cycle progression via inhibition of the pathway that promotes exit from the G(1) phase of the cell cycle. Furthermore, the clinical applicability of NC381 was evaluated in an in vivo murine xenograft model of human NSCLC (NCI-H460). NC381 treatment resulted in significant inhibition of tumor growth. Given the poor prognosis and the limited treatment options available, the present results underscore the potential of NC381 in the treatment of human NSCLC.

Efficacy of flutrimazole 1% powder in the treatment of tinea pedis

The aim of the study was to compare the efficacy and tolerability of flutrimazole 1% powder vs. bifonazole 1% powder in treating tinea pedis. A multicentre, double blind, randomized, parallel and comparative study was conducted. Two hundred and twenty-two patients with clinically and mycologically confirmed tinea pedis were randomized to flutrimazole (n = 136) or bifonazole (n = 138) 1% powder applied twice daily for 4 weeks. The corresponding clinical cure rates were assessed at 2 and 4 weeks of treatment, and the global (clinical and mycological) cure rates were determined at the fourth week. Clinical cure rates were 83.5 and 82.4% for flutrimazole and bifonazole, respectively (95% CI: -0.0806 to 0.1009). Global cure rates were observed in 65.3 and 70.1% of patients treated with flutrimazole and bifonazole, respectively (95% CI: -0.0828 to 0.1779). Three non serious adverse events at the application site--itching (one patient per group) and dishydrotic eczema (one patient treated with flutrimazole)--were recorded during the study. These results support that flutrimazol 1% powder applied twice daily for a duration of 4 weeks is highly effective in the treatment of tinea pedis, showing a similar therapeutic profile with that of bifonazole 1% powder.

K+ currents generated by NMDA receptor activation in rat hippocampal pyramidal neurons

Long lasting outward currents mediated by Ca2+-activated K+ channels can be induced by Ca2+ influx through N-methyl-D-aspartate (NMDA)-receptor channels in voltage-clamped hippocampal pyramidal neurons. Using specific inhibitors, we have attempted to identify the channels that underlie these outward currents. At a holding potential of -50 mV, applications of 1 mM NMDA to the soma of cultured hippocampal pyramidal neurons induced the expected inward currents. In 44% of cells tested, these were followed by outward currents (average amplitude 60 +/- 7 pA) that peaked 2.5 s after the initiation of the inward NMDA currents and decayed with a time constant of 1.4 s. In 43% of those cells exhibiting an outward current, SK channel inhibitors, UCL 1848 (100 nM) and apamin (100 nM) abolished the outward current. In the remainder of the cells, the outward currents were either insensitive or only partly inhibited (44 +/- 4%) by 100 nM UCL 1848. In these cells, the outward currents were reduced by the slow afterhyperpolarization (sAHP) inhibitors, muscarine (3 microM; 43 +/- 9%), UCL 1880 (3 microM; 34 +/- 10%), and UCL 2027 (3 microM; 57 +/- 6%). Neither the BK channel inhibitor, charybdotoxin (100 nM), nor the Na+/K+ ATPase inhibitor, ouabain (100 microM), reduced these outward currents. Irrespective of the pharmacology, the time course of the outward current did not differ. Interestingly, no correlation was observed between the presence of a slow apamin-insensitive afterhyperpolarization and an outward current insensitive to SK channel blockers following NMDA-receptor activation. It is concluded that an NMDA-mediated rise in [Ca2+]i can result in the activation of apamin-sensitive SK channels and of the channels that underlie the sAHP. The activation of these channels may, however, depend on their location relative to NMDA receptors as well as on the spatial Ca2+ buffering within individual neurons.

Tritylamino aromatic heterocycles and related carbinols as blockers of ca 2+-activated potassium ion channels underlying neuronal hyperpolarization

A series of novel aromatic tritylamino heterocycles has been synthesized and the compounds have been tested in comparison with clotrimazole for their ability to inhibit the slow afterhyperpolarization current (sI (AHP)) in cultured rat hippocampal pyramidal neurones. Some analogues of the clotrimazole metabolite, 2-chlorophenyl-diphenyl methanol, having different chlorination substitution in the triphenyl group have also been examined. Two compounds in particular, 3-[(2-chlorophenyl)-diphenylmethylamino] pyridine (3a, UCL 1880) and 2-tritylaminothiazole (6, UCL 2027), are of special interest; they are effective blockers of the sI (AHP) (IC (50) = 1.1-1.2 microM) and are much more selective than clotrimazole since they have less effect on the high voltage-activated Ca2+ current.

Double-blind randomized dose-finding study in acute vulvovaginal candidosis. Comparison of flutrimazole site-release cream (1, 2 and 4%) with placebo site-release vaginal cream

A double-blind randomized comparative phase II study of flutrimazole site-release vaginal cream (1, 2 and 4%) with placebo site-release vaginal cream was undertaken in patients with acute vulvovaginal candidosis. Vaginitis was demonstrated by both positive findings on microscopic examination of vaginal smears and positive culture as well as by the presence of clinical signs and symptoms. The vaginal monodose treatment was inserted in the evening at bedtime using a vaginal applicator and, in addition, all four groups of patients received additional topical external cream for application to the vulva twice-daily for 7 days; the placebo group received a placebo cream and the active therapy groups all received a 2% flutrimazole cream. A total of 133 patients who were seen over a 10-month period were screened and randomized: five patients did not take the allocated medication, and four patients whose menstrual period began shortly after study entry were excluded from the study, leaving 124 patients who were randomly allocated to receive a monodose vaginal 1% cream (regimen A, 28 patients), a monodose vaginal 2% cream (regimen B, 32 patients), a monodose vaginal 4% cream (regimen C, 31 patients) or a monodose vaginal placebo cream (regimen D, 33 patients). At the assessment 9 days after the end of therapy the proportion of patients who were cured was 82% in group A, 87.4% in group B, 83.8% in group C and 63.5% in group D. Three patients (10.7%) in group A, four (12.5%) in group B, one (3.2%) in group C and 12 (36.36%) in group D did not respond to the treatment. One patient (3.5%) in group A, and two patients (6.4%) in group C terminated the treatment prematurely due to intolerance. There was a significant association between Candida glabrata and treatment failure (P < 0.04) and C. glabrata and carrier state (P = 0.01) in vagina (chi 2 test, P = 0.01) and vulvovagina (chi 2 test, P = 0.00001). At the assessment 4 weeks after the end of therapy the proportion of cured patients was 60.6% in group A, 78% in group B, 80.6% in group C and 48.4% in group D. Group D (placebo) versus group B (2%) and group C (4%) showed a significant difference (P = 0.01 and P = 0.007, respectively). Although there were no significant differences in clinical and mycological activity between the three active groups, group B (flutrimazole 2% site-release vaginal cream) was chosen for clinical use due to its tolerance profile. Seven patients (25%) in group A, three (9.3%) in group B, two (6.4%) in group C and five (15.1%) in group D relapsed 4 weeks after the end of therapy; the relapse rate was not significantly associated with positive culture results 9 days after treatment. There was a significant association between C. glabrata and the carrier state (P < 0.01). The overall ineffective treatment (includes failures at control 1, relapses at control 2 and premature terminations) was 39% in group A, 21.7% in group B, 16% in group C and 51.3% in group D. There was a significant difference in the overall ineffective treatment when C and D groups were compared with placebo (P = 0.01 and P = 0.003, respectively).

Mycosporine-like amino acids in the marine dinoflagellate Gyrodinium dorsum: induction by ultraviolet irradiation

Cultures of the marine dinoflagellate Gyrodinium dorsum have been exposed to polychromatic radiation (photosynthetically active radiation and UV) from a solar simulator for up to 72 h. Different irradiance spectra in the ultraviolet are produced by inserting cut-off filters between lamp and samples. The mycosporine-like amino acid (MAA) content and composition are investigated by spectroscopic and chromatographic analysis. The study reveals that G. dorsum contains a complex mixture of several aminocyclohexenimine-MAAs and one aminocyclohexenone-MAA. UV irradiation around 320 nm induces an increase in the concentration of all MAAs in the samples. In contrast, exposure to short-wavelength UV-B radiation results in decreased overall MAA production. Furthermore, there is a spectral shift in the absorption of the MAA mixture towards shorter wavelengths, indicating that short-wavelength UV-B induces an altered MAA composition. The amount of MAAs is normalized to the chlorophyll a concentration.

Topical treatment of dermatophytosis and cutaneous candidosis with flutrimazole 1% cream: double-blind, randomized comparative trial with ketoconazole 2% cream

In a double-blind, randomized study the efficacy and tolerance of flutrimazole 1% cream were compared with ketoconazole 2% cream, applied once daily for 4 weeks, in 60 patients with culturally proven dermatophytosis (47 patients) or cutaneous candidosis (13 patients). Both groups of patients and distribution of target lesions were similar. The sum of clinical scores had an even distribution in both groups at the end of treatment. The proportion of patients with negative microscopy and culture after 4 weeks of treatment was 70% in the flutrimazole group and 53% in the ketoconazole group; seven ketoconazole-treated patients (23%) compared with two flutrimazole-treated patients (6.6%) were asymptomatic carriers (clinically cured with positive cultures) at the end of treatment. At the assessment 6 weeks after the end of therapy the percentages of flutrimazole- and ketoconazole-treated patients with negative mycology were 57 and 70%, respectively. There were one relapse (3.3%) in the ketoconazole group and four (13.3%) in the flutrimazole group. One patient treated with ketoconazole (3%) had a premature termination due to adverse events attributable to the medication. The results of this study show that flutrimazole 1% cream is as effective and safe as ketoconazole 2% cream for Candida and dermatophyte skin infections.

Clotrimazole is a potent vasodilator of the rat coronary microcirculation

Clotrimazole (CLT), used in the treatment of patients with sickle cell disease, directly blocks Ca2+-activated K+ (K+<INF POS="STACK">Ca) channels in red cells and in portal vein smooth muscle cells by a cytochrome P450(cyt P450)-independent mechanism. Therefore, we examined the effects of CLT on vasomotor tone of coronary arterioles. Rat coronary arterioles (80-180 micro(m) in diameter) were studied in vitro in a pressurized no-flow state with a video microscopy. CLT (0.1 micromol/L) elicited in nonprecontracted vessels a small contraction (<10% baseline diameter, P < 0.05 vs time control), consistent with blockade of a hyperpolarizing K+ channel. However, similar contraction was produced by the cyt P450 blocker 17-octadecynoic acid (17-ODYA, 100 micromol/L), suggesting possible involvement of arachidonate metabolites of cyt P450. In contrast, microvessels precontracted with the thromboxane A2 analog U46619 dilated in response to CLT [>90% relaxation of the U46619-induced precontraction at 100 micromol/L (P < 0.01 vs time control)] and its structural analogs flutrimazole (FLT), UR-4055, UR4057, UR-4058, and UR-4059. This relaxation was cyt P450-independent, since the in vivo CLT metabolite (CLT-carbinol) was equipotent with CLT, and 17-ODYA did not promote relaxation. CLT-induced dilation was not inhibited by the nitric oxide synthase inhibitor NGnitro-l-arginine (100 micromol/L, P > 0.5) or affected by endothelial denudation (P > 0.5). Thus, CLT at concentrations >1 micromol/L is a potent vasodilator of rat coronary arterioles. This dilation is likely mediated through a vascular smooth muscle mechanism independent of cyt P450 and is not modulated by nitric oxide or by the endothelium. This effect may arise from CLT's reported ability to inhibit voltage-gated Ca2+ channels or to inhibit, in some tissues, Ca2+ release from intracellular stores. The CLT- and FLT-induced relaxation may be a property common to this class of drugs and have clinical applicability.

Absorption and excretion of radioactivity after intravaginal administration of an advanced delivery system of 14C-flutrimazole vaginal cream to postmenopausal women

In order to improve the effectiveness of treatment of vaginal yeast infections, flutrimazole, (CAS 119006-77-8), a broad spectrum local imidazolic fungicide, has been formulated in an advanced delivery system (Site Release, here in after briefly referred to as SR) designed to improve vaginal retention of the drug. To determine the extent of absorption of 14C-flutrimazole from this formulation, the absorption and excretion of total radioactivity have been studied in healthy postmenopausal female volunteers after intravaginal administration of approximately 5 g of SR Vaginal Cream containing 2% 14C-flutrimazole. Concentrations of unchanged flutrimazole have also been measured in plasma and urine, using a validated gas chromatography-mass spectrometry method. The rate of absorption was slow, with a mean peak plasma radioactivity concentration, Cmax, of 56 ng equivalents/ml, achieved at a mean Tmax of 28 h. Corresponding parameters for flutrimazole were 1.94 ng/ml at 24 h. At 24 h post-dose, unchanged flutrimazole represented only 3% of plasma total radioactivity which indicates that flutrimazole is extensively metabolised in man. Total radioactivity and unchanged flutrimazole were eliminated from plasma with terminal half-lives of 37 and 22 h, respectively. From the proportion of the radioactive dose excreted in urine and faeces, the maximal extent of absorption indicated for the intravaginal dose was about 8%, which is similar to that observed with other imidazolic compounds administered by this route. Thus, the formulation achieves the aim of prolonged drug action through the maintenance of therapeutic concentrations of the drug at the site of infection without notably increased absorption.

Influence of formulation on the in vitro transdermal penetration of flutrimazole

Flutrimazole (1-[(2-fluorophenyl)(4-fluorophenyl)phenylmethyl]-1 H-imidazole, CAS 119006-77-8, UR-4056) is a new wide spectrum local imidazolic antifungal agent that has already been formulated as a dermal cream (FDC). A comparative study was carried out of the release of flutrimazole from two emulsions in which the drug has been incorporated differently: one dissolved in the oily phase (E24) and the other dispersed in the aqueous formulation phase (E25). Based on the E25 formulation, two more dermal creams were prepared, E27 with benzyl alcohol and E28 with diazolidinyl urea as preservative agents. A comparative study of transdermal penetration including E27, E28, FDC (reference 1% flutrimazole dermal cream) and 1% flutrimazole hydroalcoholic solution was also performed. An amount of the sample dosage form containing 10 mg of flutrimazole was applied to a Franz type cell. The penetration membrane used was cellulose acetate in the release studies and human skin provided by a plastic surgery clinic in the transdermal penetration study. The amount released after 7 h was 36.3 +/- 4.9 micrograms when flutrimazole was dissolved (E24) and 35.9 +/- 5.3 micrograms when flutrimazole was dispersed (E25). Although the differences were not significant, the cream with dispersed flutrimazole was selected for further penetration studies due to its better stability observed in previous studies. The amounts of drug penetrated after 44 h were 31.3, 41.5, 38.3 and 186.5 micrograms for E27, E28, FDC dermal creams and topical hydroalcoholic solution, respectively. The solution showed a statistically significant difference (p < 0.05) from the other formulations, however, no differences were observed between the dermal cream formulations. No differences were neither obtained between the different dermal creams when the amount of drug retained in the skin was compared. This allows to assert that the excipients used do not have different influences on transdermal penetration. In all cases, the mean quantity penetrated in relation to the dose applied was at most 0.5%. These results allow to infer that flutrimazole shows scarce transdermal penetration. Further, the amount of flutrimazole retained per gram of skin is more than 100 times the MIC per gram obtained in previous in vitro studies. It may be assumed that the topical application of the new formulations assayed would allow to obtain a good therapeutic response.

1-trityl-4-nitroimidazole

X-ray analysis confirmed the configuration of the title N1-alkylated C4-nitroimidazole inhibitor. The plane of the imidazole ring, sitting on an axis of the trityl propeller, bisects the angle between two phenyl rings, while the nitro group extends over the third. Modeling of the interactions between the cytochrome P450 and the title compound (C22H17N3O2) has been performed on the basis of the crystal structures of 1-trityl-4-nitroimidazole and bacterial cytochrome P450BM-3. The replacements and deletions in the sequence of the latter has been performed to match mammalian cytochrome P450-IIIA1. The modeling explained why inhibitors with a C4-substituted imidazole ring showed lower effectivity than those without substituents, as an additional group of atoms at C4 prevents close interactions of the imidazole ring with the heme Fe atom.

Topical anti-inflammatory properties of flutrimazole, a new imidazole antifungal agent

The topical anti-inflammatory properties of flutrimazole, a new imidazole antifungal, have been evaluated. Flutrimazole inhibited mouse ear oedema induced by arachidonic acid, tetradecanoylphorbol-acetate and dithranol, with IC50 values of 3.32, 0.55 and 2.42 mumols/ear, respectively. Ketoconazole showed similar potency in arachidonic acid and dithranol models (IC50 = 3.76 and 2.41 mumols/ear) whereas it was less active against tetradecanoylphorbol acetate (IC50 = 1.96 mumols/ear). The standard anti-inflammatory sodium diclofenac was overall slightly more potent than antifungals (IC50 = 2.23, 0.57 and 0.57 mumols/ear against arachidonic acid, tetradecanoylphorbol acetate and dithranol, respectively). Both 2% flutrimazole and 2% ketoconazole creams, applied topically, inhibited carrageenan-induced rat paw oedema by about 40%. Under the same conditions, 1% flutrimazole and diclofenac creams inhibited by 26 and 54%, respectively. Flutrimazole may work through the inhibition of 5-lipoxygenase, as it inhibited LTB4 production by human granulocytes with an IC50 value of 11 microM (IC50 value for ketoconazole was 17 microM), whereas ram seminal vesicle cyclooxygenase was only inhibited by 16% at a concentration of 25 microM. Drugs such as flutrimazole, with dual anti-inflammatory/antifungal activity, may be advantageous in the treatment of topical fungal infections with an inflammatory component.

A double-blind, randomized comparative trial: flutrimazole 1% solution versus bifonazole 1% solution once daily in dermatomycoses

In a double-blind, randomized study the efficacy and tolerance of flutrimazole 1% solution were compared with bifonazole 1% solution, applied once daily for 4 weeks, in 40 patients with culturally proven dermatophytosis or cutaneous candidosis. Forty patients with mycologically proven pityriasis versicolor were treated with once-daily application for 1 week. The four groups of patients and distribution of target lesions were similar, although in the flutrimazole group more patients had cutaneous candidosis (n = 8 versus n = 1). The distribution of the sum of clinical scores was also similar in both groups. At the end of therapy the proportion of patients with negative microscopy and culture was 85% in the flutrimazole group and 65% in the bifonazole group. There was a significant difference (P = 0.022) in terms of efficacy, since 80% of patients in the flutrimazole group versus 40% in the bifonazole group were judged to have received effective treatment. At the assessment 6 weeks after the end of therapy the percentages of flutrimazole- and bifonazole-treated patients with negative mycology were 75% and 65% respectively. There were two relapses (one in each group), which represents a 5% rate. Fifteen flutrimazole-treated patients (75%) compared with 12-bifonazole-treated patients (60%) had overall effective therapy. Two patients treated with bifonazole (10%) and one treated with flutrimazole (5%) had a premature termination due to adverse events attributable to the medication. On assessment 3 weeks after the end of treatment, the patients with pityriasis versicolor were all clinically and mycologically healed with negative fluorescence, including the patients who withdrew from the full course of treatment (one in each group). Nine weeks after the end of therapy all the patients remained cured, with no relapses. The overall incidence of adverse events (mild local reactions such as irritation, burning and itching) was one and seven cases for bifonazole and flutrimazole respectively. One patient in each group had to abandon treatment owing to severe intolerance.

The anti-Malassezia furfur activity in vitro and in experimental dermatitis of six imidazole antifungal agents: bifonazole, clotrimazole, flutrimazole, ketoconazole, miconazole and sertaconazole

Bifonazole, clotrimazole, flutrimazole, ketoconazole, miconazole and sertaconazole were tested for their activity against 23 isolates of Malassezia furfur by agar dilution in vitro. Topical formulations of the same agents were evaluated for efficacy against M. furfur skin infections in guinea pigs in vivo. The most potent inhibitor in vitro was ketoconazole (geometric mean minimum inhibitory concentration 0.51 microgram ml-1), followed by bifonazole (8.1 micrograms ml-1), then miconazole (14 micrograms ml-1), clotrimazole (15 micrograms ml-1) and flutrimazole (16 micrograms ml-1), with sertaconazole the least active (52 micrograms ml-1). In animal experiments involving three consecutive days of topical treatments, bifonazole 1% cream, clotrimazole 1% cream, flutrimazole 1% and 2% creams, ketoconazole 2% cream and shampoo and miconazole 2% cream all reduced M. furfur dermatitis lesion severity below that of untreated control animals; however, sertaconazole 2% gel and cream showed no reduction in lesion severity below control. The results confirm that ketoconazole is a more potent inhibitor of M. furfur in vitro than other topical antifungal agents of its class and suggest that sertaconazole is the least effective of such agents among those tested.

Flutrimazole 1% dermal cream in the treatment of dermatomycoses: a multicentre, double-blind, randomized, comparative clinical trial with bifonazole 1% cream. Efficacy of flutrimazole 1% dermal cream in dermatomycoses. Catalan Flutrimazole Study Group

BACKGROUND

Flutrimazole is a new imidazole derivate. Its antifungal activity has been demonstrated in in vivo and in vitro studies to be comparable to that of clotrimazole and higher than bifonazole.

AIM

To compare the efficacy and tolerability of flutrimazole cream 1% with a reference drug, bifonazole, in the treatment of dermatomycoses, eligible for topical treatment exclusively.

METHODS

A multicentre, double-blind, randomized, parallel-group clinical trial was conducted. Patients with clinically and mycologically (KHO and/or culture) diagnosed fungal infection of the skin were included in this study and were randomized into two treatment groups: 1% flutrimazole or 1% bifonazole, applied to the affected area (target lesion) once a day. The principal criterion of efficacy, 'cure', was based on clinical and mycological assessment.

RESULTS

Four hundred and forty-nine patients were included in the study (228 flutrimazole, 221 bifonazole). 'Intention-to-treat' analysis of the data showed a difference between the treatments in terms of the rate of cure (clinical and mycological) after 4 weeks: 73% in the flutrimazole group and 65% in the bifonazole group (p = 0.05). From a safety point of view, flutrimazole and bifonazole were well tolerated, and the overall incidence of adverse effects (mainly mild local effects like irritation or burning sensation) was 5%.

CONCLUSIONS

One percent flutrimazole applied topically once a day in the treatment of fungal infections of the skin presents a better efficacy than bifonazole and a good tolerability.

Flutrimazole 1% dermal cream in the treatment of dermatomycoses: a randomized, multicentre, double-blind, comparative clinical trial with 1% clotrimazole cream. Flutrimazole Study Group

In a multicentre, double-blind, randomized, parallel group clinical trial, the efficacy and tolerability of flutrimazole 1% dermal cream were compared with those of a reference compound, clotrimazole 1% dermal cream, applied topically twice daily for 4 weeks in patients with clinically and mycologically diagnosed fungal infection of the skin. A total of 484 patients were included in the study (244 patients received flutrimazole cream and 240 clotrimazole cream). According to an intention to treat analysis of the data, there was no difference between the treatments in terms of the rate of mycological cure after 4 weeks: 79% of patients in the clotrimazole group and 80% of patients in the flutrimazole group were mycologically cured (P = 0.83). From a safety point of view, flutrimazole and clotrimazole were well tolerated and the overall incidence of adverse reactions (mainly mild local reactions such as irritation or burning sensation) was 7%. This study shows that, in the treatment of fungal infections of the skin, topically applied flutrimazole has good efficacy, similar to that of clotrimazole, and is well tolerated.

Pharmacokinetic profile of [14C]flutrimazole following single topical application in normal and scarified skin of healthy volunteers

14C-labelled 1-[(2-fluorophenyl)(4-fluorophenyl)phenylmethyl]-1H- imidazole (flutrimazole, UR-4056, CAS 119006-77-8) was administered topically (dermally) in three male volunteers to normal skin and scarified skin, respectively. Blood, urine and faeces were collected and radioassayed by liquid scintillation counting techniques. After topical application to healthy skin area, less than 1% of flutrimazole was absorbed percutaneously from a 1% cream and the amount absorbed was excreted with the urine. Following administration of the drug to scarified skin, the proportions absorbed were very similar to those measured after application to normal skin. About 0.5% of the administered dose is recovered in urine. The absorbed amount of drug leads to very low concentrations in the circulation, lower than a few ng/ml.

Toxicity studies with flutrimazole

Studies with 1-[(2-fluorophenyl)(4-fluorophenyl)phenylmethyl]-1H- imidazole (flutrimazole, CAS 119006-77-8), a new topical imidazole antifungal agent, have been carried out to investigate the acute toxicity of the active substance in mice and rats, as well as the acute ocular and dermal irritation in rabbits, the dermal tolerance after repeated dose (21 days) applications in rabbits, and the sensitising, photoallergic and phototoxic potential in guinea pigs using 1% flutrimazole cream. LD50 values after oral or intraperitoneal administration were greater than or equal to 1000 mg/kg in both mice and rats, which reveal a very low acute toxicity of flutrimazole. No differences were found between the excipient and 1% flutrimazole cream in the acute ocular and dermal irritation studies in rabbits, the irritation indexes being indicative of no lesions due to flutrimazole. Cumulative dermal irritation studies in rabbits showed an improved local tolerance of a skin cream containing 1% flutrimazole as compared to a commercial skin cream containing 1% clotrimazole. The irritation indexes were 1.2 and 3.7, respectively (p less than 0.01). The corresponding histophatological findings confirmed the better local tolerance of 1% flutrimazole cream. Furthermore, it has been found that flutrimazole cream lacks sensitising potential (Magnusson and Kligman test), is also devoid of phototoxic potential and does not induce photoallergic reactions in guinea pigs, these data being confirmed by histopathological studies. These results, together with the very slight systemic absorption rate of flutrimazole from the 1% topical drug form, clearly show that no restrictions should be taken in the use of the cream for reasons of systemic toxicity or dermal tolerance.

Local and systemic tolerance of flutrimazole skin creams following single and repeated topical application in healthy volunteers

A double-blind, randomized phase I study was performed in 21 healthy volunteers to evaluate the dermal tolerance of skin creams containing 1% and 2% 1-[(2-fluorophenyl)(4-fluorophenyl)phenylmethyl]-1H-imidazole (flutrimazole, UR-4056, CAS 119006-77-8) or only the excipient, versus a commercial skin cream containing 1% clotrimazole. The study was carried out using the patch-test procedure performed in three stages: 1. single application in the back skin; 2. induction period (usage test) using three skin areas on the volar side of the forearm of each subject, where skin cream samples were applied once a day for a period of three weeks; and 3. after a wash-out period of two weeks, challenge applications in the back and forearm skin. The systemic tolerance of the formulations was also tested. There was no evidence of allergic sensitization after the application of flutrimazole creams, or their excipients, with signs of mild and doubtful skin reactions being observed in few subjects with all formulations. Furthermore, no systemic side effects after topical administration were detected throughout the study.

In vitro and in vivo studies with flutrimazole, a new imidazole derivative with antifungal activity

1-[(2-Fluorophenyl)(4-fluorophenyl)phenylmethyl]-1H-imidazole (flutrimazole, UR-4056, CAS 119006-77-8) is a new topical imidazole antifungal agent which displays potent broad-spectrum in vitro activity against dermatophytes, filamentous fungi and yeasts, saprophytic and pathogenic to animals and humans (MIC = 0.025-5.0 micrograms/ml). In most of these studies the activity of flutrimazole was comparable to that of clotrimazole and markedly higher than that of bifonazole (MIC differences of greater than or equal to 1 order of magnitude). Tested against Scopulariopsis brevicaulis (8 strains), both flutrimazole and clotrimazole exhibited fungistatic and fungicidal activity, and clotrimazole appeared something less active (MIC = 0.3-2.5 micrograms/ml) than flutrimazole (MIC = 0.15-0.6 micrograms/ml). In animal experiments, topical application of 1% and 2% flutrimazole, as a cream or solution, was highly effective in models of rat vaginal candidiasis and guinea-pig trichophytosis, giving a rate of cured or cured plus markedly improved animals higher than 80%. Flutrimazole shares the mode of action of other imidazole or triazole-containing antifungals, i.e. inhibition of fungal lanosterol 14 alpha-demethylase, as it strongly inhibits ergosterol biosynthesis in a cell-free homogenate of Candida albicans, with an IC50 value of 0.071 mumol/l.

Percutaneous absorption and skin distribution of [14C]flutrimazole in mini-pigs

The percutaneous absorption and skin distribution of a skin cream containing 1% 14C-labelled 1-[(fluorophenyl) (4-fluorophenyl) phenylmethyl]-1H-imidazole (flutrimazole, UR-4056, CAS 119006-77-8) was studied in minipigs. The same dose of flutrimazole was administered i.v. and topically (as a cream) on scarified skin according to a crossover protocol. Samples of urine and faeces were taken at various intervals after administration, and radioactivity was measured. The percentage of radioactivity accumulated in urine after topical and intravenous administration were 1.46% and 41.7%, respectively. In faeces, the percentage of radioactivity observed was 6.0% after intravenous administration, and none was detected after topical application. In order to study the distribution and penetration of [14C]flutrimazole, the cream was applied to intact and scarified skin. At various intervals after administration, skin samples were taken. The samples for the autoradiographic studies were cut transversely, and for the measurement of the levels of radioactivity at different skin depths, slices were cut parallel to the cutaneous layers. The results obtained indicate that [14C]flutrimazole penetrates quickly into the different epidermic layers and is retained mainly in the strata spinosum, granulosum and basale. The stratum basale possibly acts as a selective barrier preventing the penetration of the compound into the dermis. The percentage of radioactivity in the stratum corneum is lower than that detected in all the other epidermic layers taken together. The stratum corneum offers low resistance to penetration by the flutrimazole, which very probably crosses the epidermic strata by a transcellular route.

Pharmacokinetic study of [14C]flutrimazole after oral and intravenous administration in dogs. Comparison with clotrimazole

This trial involved a comparative study using 6 Beagle dogs on the pharmacokinetics of 14C-labelled 1-[(2-fluorophenyl)(4-fluorophenyl)phenylmethyl]-1H-imidazole (flutrimazole, CAS 119006-77-8) and [14C]clotrimazole labelled in the imidazole ring. On the basis of a cross-over trial, each animal received a dose of 5 mg/kg (approx. 100 microCi) [14C]flutrimazole and [14C]clotrimazole, both intravenously and orally. The levels in plasma, urine and faeces of the total radioactivity, unchanged drug and the [14C]imidazole formed by metabolization of the unchanged drug were determined. Flutrimazole presented a biological half-life (t1/2) of 14.4 +/- 3.8 h and a clearance (Cl) of 6.7 +/- 0.8 l/h, while the values for clotrimazole were very different: t1/2 4.6 +/- 0.8 h and Cl: 13.6 +/- 1.0 l/h. After oral administration a fraction of absorbed dose (f) of 78 +/- 21% and bioavailability of 8.9 +/- 6.1% were calculated for flutrimazole. For clotrimazole, these were: 52 +/- 10% and 4.9 +/- 1.9%, respectively. Both drugs showed a significant first-pass effect, with 90% of the absorbed dose being metabolized before reaching the systemic circulation. The total recovery of radioactivity in faeces and urine 5 days after i.v. and oral administration was 58% and 68%, respectively, for [14C]flutrimazole, and 81% and 79% for [14C]clotrimazole. In both cases, most of the radioactivity was recovered in the faeces. The high radioactivity obtained in faeces after i.v. administration of both drugs confirms biliary elimination. For both flutrimazole and clotrimazole, less than 1% of the total recovered in the urine after i.v. administration was recovered as unchanged drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Clotrimazole as an inhibitor of benzo[a]pyrene metabolite-DNA adduct formation in vitro and of microsomal mono-oxygenase activity

The fungistatic drug clotrimazole (1-[(o-chlorophenyl)diphenylmethyl]imidazole) in concentrations of 5 or 50 microM completely prevented the formation of benzo[a]pyrene metabolite-DNA adducts in vitro catalyzed by liver microsomes from phenobarbital-or 3-methylcholanthrene-treated rats, respectively. Microsomal 7-ethoxycoumarin de-ethylase and aryl hydrocarbon hydroxylase were effectively inhibited by clotrimazole and three clotrimazole derivatives in all induction states tested, with I50 values down to 7 x 10(-8) M. The mechanism of inhibition was noncompetitive in phenobarbital-stimulated microsomes. Microsomal epoxide hydratase in vitro was enhanced up to 450% by clotrimazole and one of the analogues in concentrations between 5 and 500 microM. Clotrimazole spectrally interacted with reduced cytochrome P-450, exhibiting a double-banded Soret region with peaks at 427 and 446 nm, and partially prevented cytochrome P-450-CO complex formation. When administered in vivo, clotrimazole effectively induced cytochrome P-450 content, mono-oxygenase activity and epoxide hydratase activity in rat liver microsomes. The induction pattern was similar to that obtained with phenobarbital. The analogues were less potent inducers.

Frozen conformers of clotrimazole: reaction of imadazole with 1-Chloro-9-hydroxy-9-phenylxanthene

1-Chloro-9-hydroxy-9-phenylxanthene reacts with imidazole at 180 degrees to form a 5:1 mixture of the 9-(imidazo-1-yl)- and 9-(imidazo-2-yl)-1-chloro-9-phenylxanthenes. These products lack significant antifungal activity.