Antifungal; sterol biosynthesis; cytochrome P450 14α-demethylase

A wide range of fungi, including Candida spp., Trichosporon beigelii, Candida neoformans, and A. fumigatus, are susceptible to the effects of ravuconazole. The range of the MIC90 is 0.025 to 0.39 mg/mL. With MICs ranging from 0.05 to 0.39 mg/mL, raviconazole exhibits comparatively higher levels of activity against three strains of Candida krusei. With MICs ranging from 0.05 to 0.39 mg/mL, raviconazole exhibits good activity against T. mentagrophytes, T. rubrum, M. gypseum, and M. canis[1]. About 40 times more active than fluconazole and two to four times more potent than itraconazole are ravuconazoleis against yeasts. Most aspergilli are inhibited by ravuconazole and itraconazole, and against half of the isolates, the activity is cidal. Inactive against Sporothrix schenckii and zygomycetes, ravuconazole and itraconazole are active, albeit not cidal, against the majority of hyaline Hyphomycetes, dermatophytes, and dematiaceous fungi[2].

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ER-30346 is a novel oral triazole with a broad spectrum of potent activity against a wide range of fungi. ER-30346, with MICs at which 90% of the strains tested are inhibited (MIC90s) ranging from 0.025 to 0.78 microgram/ml, was 4 to 32 times more active than itraconazole, fluconazole, and amphotericin B against Candida albicans, Candida parapsilosis, and Candida glabrata. Against Candida tropicalis, ER-30346, with an MIC90 of 12.5 micrograms/ml, was 2 to > 8 times more active than itraconazole and fluconazole, but was 16 times less active than amphotericin B. ER-30346 (MIC90, 0.78 microgram/ml) was four to eight times more active than fluconazole and amphotericin B and had activity comparable to that of itraconazole against Trichosporon beigelli. The MIC90s of ER-30346 were 0.10 microgram/ml for Cryptococcus neoformans and 0.39 microgram/ml for Aspergillus fumigatus. ER-30346 was 2 to 8 times more active than itraconazole and amphotericin B and 32 to > 256 times more active than fluconazole. ER-30346 also showed good activity against dermatophytes, with MICs ranging from 0.05 to 0.39 microgram/ml, and its activity was comparable to or 2 to 16 times higher than those of itraconazole and amphotericin B and > 32 times higher than that of fluconazole.[1]

When ravuconazole is administered at doses ranging from 2 to 40 mg/kg of body weight, both the maximum concentration of the drug in plasma and the area under the concentration-time curve exhibit good linearity. When compared to the control treatment, the administration of 2.5 mg/kg of raveconazole significantly delays mortality. Additionally, ravuconazole has a significant positive therapeutic effect on systemic cryptococcosis[1]. When compared to the CFU in the lungs of the controls, ravuconazole dramatically lowers the CFU in the lungs. Ravuconazole is more effective than itraconazole and equally effective as fluconazole in reducing the number of CFU in oral swabs when compared to the control group's oral swabs in an experimental model of oral candidiasis in rats. [3].

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Ravuconazole/ER-30346 is a novel oral triazole with a broad spectrum of potent activity against a wide range of fungi. In the present study, we investigated the therapeutic effects of oral ER-30346 on experimental local infections caused by Aspergillus fumigatus, Candida albicans, and Cryptococcus neoformans and compared them with those of itraconazole and fluconazole. In experimental murine models of pulmonary aspergillosis, candidiasis, and cryptococcosis, ER-30346 reduced the numbers of CFU in the lungs significantly compared with the numbers of CFU in the lungs of the controls (P < 0.05). ER-30346 was as effective as or more effective than itraconazole against pulmonary aspergillosis. Against pulmonary candidiasis and cryptococcosis, ER-30346 was more effective than itraconazole and was as effective as fluconazole. ER-30346 was also effective against pulmonary candidiasis caused by fluconazole-resistant C. albicans. In mice with intracranial cryptococcosis, ER-30346 reduced the numbers of CFU in the brains significantly compared with the numbers of CFU in the brains of the controls (P < 0.05) and was more effective than itraconazole and as effective as fluconazole. In an experimental model of oral candidiasis in rats, ER-30346 reduced the numbers of CFU in oral swabs significantly compared with the numbers of CFU in oral swabs from the controls (P < 0.05) and was more effective than itraconazole and as effective as fluconazole. Thus, ER-30346 shows efficacy in murine aspergillosis, candidiasis, and cryptococcosis models. Further studies are needed to determine the potential of ER-30346 for use in the treatment of these infections.[3]

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In vivo activity was evaluated with systemic infections in mice. Against systemic candidiasis and cryptococcosis, ER-30346 was comparable in efficacy to fluconazole and was more effective than itraconazole. Of the drugs tested, ER-30346 was the most effective drug against systemic aspergillosis. We studied the levels of ER-30346 in mouse plasma. The maximum concentration of drug in plasma and the area under the concentration-time curve for ER-30346 showed good linearity over a range of doses from 2 to 40 mg/kg of body weight.[1]

The antifungal activity of BMS-207147 (also known as ER-30346) was compared to those of itraconazole and fluconazole against 250 strains of fungi representing 44 fungal species. MICs were determined by using the National Committee for Clinical Laboratory Standards (NCCLS)-recommended broth macrodilution method for yeasts, which was modified for filamentous fungi. BMS-207147 was about two- to fourfold more potent than itraconazole and about 40-fold more active than fluconazole against yeasts. With the NCCLS-recommended resistant MIC breakpoints of > or = 1 microg/ml for itraconazole and of > or = 64 microg/ml for fluconazole against Candida spp., itraconazole and fluconazole were inactive against strains of Candida krusei and Candida tropicalis. In contrast, all but 9 (all C. tropicalis) of the 116 Candida strains tested had BMS-207147 MICs of < 1 microg/ml. The three triazoles were active against about half of the Candida glabrata strains and against all of the Cryptococcus neoformans strains tested. The three triazoles were fungistatic to most yeast species, except for BMS-207147 and itraconazole, which were fungicidal to cryptococci. BMS-207147 and itraconazole were inhibitory to most aspergilli, and against half of the isolates, the activity was cidal. BMS-207147 and itraconazole were active, though not cidal, against most hyaline Hyphomycetes (with the exception of Fusarium spp. and Pseudallescheria boydii), dermatophytes, and the dematiaceous fungi and inactive against Sporothrix schenckii and zygomycetes. Fluconazole, on the other hand, was inactive against most filamentous fungi with the exception of dermatophytes other than Microsporum gypseum. Thus, the spectrum and potency of BMS-207147 indicate that it should be a candidate for clinical development [2].

Antifungal susceptibility test methods.[2]
All isolates (except Malassezia furfur) were tested by the reference broth macrodilution method outlined by the NCCLS and modified for antifungal testing of filamentous fungi. BMS was obtained from Eisai Co., FLU was from Pfizer, ITR was from Janssen Pharmaceutica, and AMB was from Bristol-Myers Squibb Co.
The interpretative MIC breakpoints for FLU and ITR are obtained from the NCCLS guidelines; these breakpoints were meant as interpretative guidelines for Candida spp. The NCCLS-recommended breakpoints for FLU are as follows: ≤8 μg/ml, susceptible; 16 to 32 μg/ml, susceptible-dose dependent (S-DD); and ≥64 μg/ml, resistant. For ITR, the NCCLS-recommended MIC breakpoints as follows: ≤0.13 μg/ml, susceptible; 0.25 to 0.5 μg/ml, S-DD; and ≥1 μg/ml, resistant. At this point, no interpretative MIC breakpoints for BMS have been established. For the purpose of discussion of the MIC results in this report, we will use the ITR interpretative breakpoints for BMS, given that both compounds achieve the same peak levels in plasma in dogs. As for AMB, no interpretative MIC breakpoints have been recommended by the NCCLS, though Candida isolates with AMB MICs of >1 μg/ml appear resistant in animal models. Thus, AMB resistance will be defined in this study as AMB MICs of ≥2 μg/ml when the NCCLS RPMI 1640 method is used.
Broth macrodilution for yeasts was performed according to the guidelines of the NCCLS and modified for filamentous fungi by the method of Espinel-Ingroff and Kerkering. The agar dilution method used for Malassezia furfur was described previously.
The MIC endpoints by the broth macrodilution method were determined as recommended by the NCCLS. AMB MICs were defined as the lowest drug concentrations which inhibited all visible growth (i.e., 100% inhibition). FLU, ITR, and BMS MICs were defined as the lowest drug concentrations which inhibited 80% of the growth in the growth control tube (as determined by comparison with a 1:5 dilution of the growth control), except with Malassezia furfur, where 100% growth inhibition was the endpoint.

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MFCs. [2]
Minimum fungicidal concentrations (MFCs) were determined by subculturing 0.1 ml from each tube with no visible growth in the MIC broth macrodilution series onto drug-free SDA plates, as previously described. Colony counts were determined, and the MFCs were defined in accordance with the level of decrease in the number of CFU per milliliter, i.e., MFC99 means a 99% reduction in the number of CFU of the final inoculum size per milliliter, MFC95 means a 95% reduction, and MFC90 means a 90% reduction.

Mouse
To prepare ravuconazole, mix 10% DMSO with 0.5% CMC.For 48 hours, C. neoformans No. 3 is grown on an SDA plate at 30°C. Sterile saline is used to prepare the challenge organisms. The tail vein is the route of infection in mice (n = 5; p. 5). Oral administration of ravuconazole is initiated 1 hour after infection, twice a day for 5 days in a volume of 0.2 mL per dose. In 0.5% CMC, controls are given 10% DMSO. The dosages of ravuconazole are 8 and 32 mg/kg. Every day after the infection for 21 days, mortality is recorded. Determining the delay in mortality allows for the evaluation of drug efficacy.

[1]. In vitro and in vivo antifungal activities of ER-30346, a novel oral triazole with a broad antifungal spectrum.Antimicrob Agents Chemother. 1996 Oct;40(10):2237-42.

[2]. In vitro activity of a new oral triazole, BMS-207147 (ER-30346)Antimicrob Agents Chemother. 1998 Feb;42(2):313-8.

[3]. Efficacy of ER-30346, a novel oral triazole antifungal agent, in experimental models of aspergillosis, candidiasis, and cryptococcosis.Antimicrob Agents Chemother. 1996 Oct;40(10):2243-7.

Ravuconazole is a member of the class of triazoles that is 1-butyl-1H-1,2,4-triazole in which the butyl group is substituted at positions 2, 2, and 3 by hydroxy, 2,4-difluorophenyl, and 4-(p-cyanophenyl)-1,3-thiazol-2-yl groups, respectively (the R,R stereoisomer). It exhibits antifungal activity by inhibition of 14alpha demethylase, an enzyme involved in sterol synthesis, resulting in lysis of the fungal cell wall and fungal cell death. (NCIO4) It has a role as an ergosterol biosynthesis inhibitor, an antifungal drug, an EC 1.14.14.154 (sterol 14alpha-demethylase) inhibitor and an antileishmanial agent. It is a member of triazoles, a member of fluorobenzenes, a tertiary alcohol, a member of 1,3-thiazoles and a nitrile.
Ravuconazole is a triazole with antifungal activity. Ravuconazole inhibits 14a demethylase, an enzyme involved in sterol synthesis, resulting in lysis of the fungal cell wall and fungal cell death. (NCI04)

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Drug Indication
Investigated for use/treatment in fungal infections, aspergillosis, candidiasis, and onychomycosis.

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In this study, BMS and ITR were inhibitory at 1 μg/ml to all but one of the 16 strains of Aspergillus spp. Similarly, Hata et al. observed the consistent activity of BMS and ITR against Aspergillus spp. The antiaspergillus potencies of BMS and ITR are comparable. FLU was inactive against aspergilli. BMS and ITR were also fungicidal to 50 to 74% of the Aspergillus strains tested.
The activities of BMS and ITR against other filamentous fungi are variable compared to FLU, which was inactive against most filamentous fungi. ITR and BMS were uniformly active against dermatophytes, while FLU was less active against Microsporum gypseum. Acremonium strictum, Paecilomyces variotii, and Penicillium sp. were susceptible to BMS and ITR. Though both ITR and BMS were active against most dematiaceous fungi, ITR appeared to be somewhat more active than BMS. BMS and ITR were less active against most strains of Pseudallescheria boydii, Sporothrix schenckii, and the zygomycetes, and both were generally inactive against Fusarium spp. Unlike Aspergillus spp., BMS and ITR were not fungicidal to the other filamentous fungi.
In summary, BMS is a new triazole that is two- to fourfold more potent than ITR and up to 40-fold more active than FLU against many species of fungi. Its spectrum includes some yeast strains that are resistant to FLU. BMS is like ITR in that it is fungicidal to cryptococci and many strains of aspergilli. The in vitro profile of BMS warrants its development as a therapeutic agent in humans.[2]

C22H17N5OF2S

437.46508

437.112

C, 60.40; H, 3.92; F, 8.69; N, 16.01; O, 3.66; S, 7.33

182760-06-1

Ravuconazole-d4;1329499-27-5

467825

Off-white to yellow solid powder

1.4±0.1 g/cm3

674.9±65.0 °C at 760 mmHg

362.0±34.3 °C

0.0±2.2 mmHg at 25°C

1.666

3.89

1

8

6

31

657

2

FC1=CC(F)=CC=C1[C@](CN2C=NC=N2)(O)[C@@H](C)C3=NC(C4=CC=C(C#N)C=C4)=CS3

OPAHEYNNJWPQPX-RCDICMHDSA-N

InChI=1S/C22H17F2N5OS/c1-14(21-28-20(10-31-21)16-4-2-15(9-25)3-5-16)22(30,11-29-13-26-12-27-29)18-7-6-17(23)8-19(18)24/h2-8,10,12-14,30H,11H2,1H3/t14-,22+/m0/s1

p-(2-((alphaR,betaR)-2,4-Difluoro-beta-hydroxy-alpha-methyl-beta-(1H-1,2,4-triazol-1-ylmethyl)phenethyl)-4-thiazolyl)benzonitrile

BMS 207147; BMS207147; BMS-207147; 182760-06-1; Ravuconazole [INN]; Benzonitrile, 4-[2-[(1R,2R)-2-(2,4-difluorophenyl)-2-hydroxy-1-methyl-3-(1H-1,2,4-triazol-1-yl)propyl]-4-thiazolyl]-; ER-30346 ;ER 30346 ; ER30346.

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 (~114.29 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (5.71 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 (5.71 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 (5.71 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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Solubility in Formulation 4: 10% DMSO+40% PEG300+5% Tween-80+45% Saline: ≥ 2.5 mg/mL (5.71 mM)

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