Interaction of the antifungal ketoconazole and its diphenylphosphine derivatives with lipid bilayers: Insights into their antifungal action

Ketoconazole (Ke) is an important antifungal drug, and two of its diphenylphosphinemethyl derivatives (KeP: Ph2PCH2-Ke and KeOP: Ph2P(O)CH2-Ke) have shown improved antifungal activity, namely against a yeast strain lacking ergosterol, suggesting alternative modes of action for azole compounds. In this context, the interactions of these compounds with a model of the cell membrane were investigated, using POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) large unilamellar vesicles and taking advantage of the intrinsic fluorescence of Ke, KeP and KeOP. Steady-state fluorescence spectra and anisotropy, including partition and aggregation studies, as well as fluorescence lifetime measurements, were carried out. In addition, the ability of the compounds to increase membrane permeability was assessed through carboxyfluorescein leakage. The membrane/water mole fraction partition coefficients (Kp,x): (3.31 ± 0.36) x105, (8.31 ± 1.60) x105 and (4.66 ± 0.72) x106, for Ke, KeP and KeOP, respectively, show that all three compounds have moderate to high affinity for the lipid bilayer. Moreover, KeP, and particularly KeOP interact more efficiently with POPC bilayers than Ke, which correlates well with their in vitro antifungal activity. Furthermore, although the three compounds disturb the lipid bilayer, KeOP is the quickest and most efficient one. Hence, the higher affinity and ability to permeabilize the membrane of KeOP when compared to that of KeP, despite the higher lipophilicity of the latter, points to an important role of Ph2P(O)CH2- oxygen. Overall, this work suggests that membrane interactions are important for the antifungal activity of these azoles and should be considered in the design of new therapeutic agents.

Exploring the impact of CYP2D6 and UGT2B7 gene-drug interactions, and CYP-mediated DDI on oxycodone and oxymorphone pharmacokinetics using physiologically-based pharmacokinetic modeling and simulation

Oxycodone is one of the most commonly used opioids to treat moderate to severe pain. It is metabolized mainly by CYP3A4 and CYP2D6, while only a small fraction of the dose is excreted unchanged into the urine. Oxymorphone, the metabolite primarily formed by CYP2D6, has a 40- to 60-fold higher mu-opioid receptor affinity than the parent compound. While CYP2D6-mediated gene-drug-interactions (GDIs) and drug-drug interactions (DDIs) are well-studied, they only account for a portion of the variability in oxycodone and oxymorphone exposure. The combined impact of CYP2D6-mediated GDIs and DDIs, CYP3A4-mediated DDIs, and UGT2B7 GDIs is not fully understood yet and hard to study in head-to-head clinical trials given the relatively large number of scenarios. Instead, we propose the use of a physiologically-based pharmacokinetic model that integrates available information on oxycodone's metabolism to characterize and predict the impact of DDIs and GDIs on the exposure of oxycodone and its major, pharmacologically-active metabolite oxymorphone. To this end, we first developed and verified a PBPK model for oxycodone and its metabolites using published clinical data. The verified model was then applied to determine the dose-exposure relationship of oxycodone and oxymorphone stratified by CYP2D6 and UGT2B7 phenotypes respectively, and administered perpetrators of CYP-based drug interactions. Our simulations demonstrate that the combination of CYP2D6 UM and a UGT2B7Y (268) mutation may lead to a 2.3-fold increase in oxymorphone exposure compared to individuals who are phenotyped as CYP2D6 NM / UGT2B7 NM. The extent of oxymorphone exposure increases up to 3.2-fold in individuals concurrently taking CYP3A4 inhibitors, such as ketoconazole. Inhibition of the CYP3A4 pathway results in a relative increase in the partial metabolic clearance of oxycodone to oxymorphone. Oxymorphone is impacted to a higher extent by GDIs and DDIs than oxycodone. We predict oxymorphone exposure to be highest in CYP2D6 UMs/UGT2B7 PMs in the presence of ketoconazole (strong CYP3A4 index inhibitor) and lowest in CYP2D6 PMs/UGT2B7 NMs in the presence of rifampicin (strong CYP3A4 index inducer) covering a 55-fold exposure range.

Preparation, characterization, and evaluation of ketoconazole-loaded pineapple cellulose green nanofiber gel

The present study involves the isolation of cellulose nanofibers from pineapple crown waste by a combined alkali-acid treatment method. The extracted pineapple nanofibers were characterized by Fourier-transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, nuclear magnetic resonance, high-resolution transmission electron microscopy, and dynamic light scattering. The extracted pineapple nanofibers were then incorporated in Carbopol 934P containing ketoconazole to prepare a ketoconazole-loaded pineapple nanofibrous gel. The prepared gel formulation was evaluated for viscosity, spreadability, extrudibility, pH, drug content, and texture profile analysis. The anticipated gel formulation was further evaluated by in vitro drug release (98.57 ± 0.58 %), ex vivo drug permeation, cytotoxicity, and histopathological studies. The permeation of the drug through skin determined by the ex-vivo diffusion study was found to be 38.27 % with a flux rate of 4.06 ± 0.26 μg/cm2/h. Further, the cytotoxicity study of pineapple nanofiber and ketoconazole-loaded nanofiber gel displayed no cytotoxic on healthy vero cells in the concentration range from 10 to 80 μg/ml. The histopathological analysis exhibited no signs of distress and inflammation. In conclusion, ketoconazole-loaded pineapple nanofiber gel could be considered as a promising delivery system for topical applications.

Vincristine Disposition and Neurotoxicity Are Unchanged in Humanized CYP3A5 Mice

Previous studies have suggested that the incidence of vincristine-induced peripheral neuropathy (VIPN) is potentially linked with cytochrome P450 (CYP)3A5, a polymorphic enzyme that metabolizes vincristine in vitro, and with concurrent use of azole antifungals such as ketoconazole. The assumed mechanism for these interactions is through modulation of CYP3A-mediated metabolism, leading to decreased vincristine clearance and increased susceptibility to VIPN. Given the controversy surrounding the contribution of these mechanisms, we directly tested these hypotheses in genetically engineered mouse models with a deficiency of the entire murine Cyp3a locus [Cyp3a(-/-) mice] and in humanized transgenic animals with hepatic expression of functional and nonfunctional human CYP3A5 variants. Compared with wild-type mice, the systemic exposure to vincristine was increased by only 1.15-fold (95% confidence interval, 0.84-1.58) in Cyp3a(-/-) mice, suggesting that the clearance of vincristine in mice is largely independent of hepatic Cyp3a function. In line with these observations, we found that Cyp3a deficiency or pretreatment with the CYP3A inhibitors ketoconazole or nilotinib did not influence the severity and time course of VIPN and that exposure to vincristine was not substantially altered in humanized CYP3A5*3 mice or humanized CYP3A5*1 mice compared with Cyp3a(-/-) mice. Our study suggests that the contribution of CYP3A5-mediated metabolism to vincristine elimination and the associated drug-drug interaction potential is limited and that plasma levels of vincristine are unlikely to be strongly predictive of VIPN. SIGNIFICANCE STATEMENT: The current study suggests that CYP3A5 genotype status does not substantially influence vincristine disposition and neurotoxicity in translationally relevant murine models. These findings raise concerns about the causality of previously reported relationships between variant CYP3A5 genotypes or concomitant azole use with the incidence of vincristine neurotoxicity.

Physiologically Based Pharmacokinetic Modeling of the Drug-Drug Interaction Between CYP3A4 Substrate Glasdegib and Moderate CYP3A4 Inducers in Lieu of a Clinical Study

Glasdegib (DAURISMO) is a hedgehog pathway inhibitor approved for the treatment of acute myeloid leukemia (AML). Cytochrome P450 3A4 (CYP3A4) has been identified as a major metabolism and clearance pathway for glasdegib. The role of CYP3A4 in the clearance of glasdegib has been confirmed with clinical drug-drug interaction (DDI) studies following the coadministration of glasdegib with the strong CYP3A4 inhibitor ketoconazole and the strong inducer rifampin. To evaluate potential drug interactions with CYP3A4 modulators, the coadministration of glasdegib with a moderate CYP3A4 inducer, efavirenz, was evaluated using physiologically based pharmacokinetic (PBPK) modeling using the Simcyp simulator. The glasdegib compound file was developed using measured physicochemical properties, data from human intravenous and oral pharmacokinetics, absorption, distribution, metabolism, and excretion studies, and in vitro reaction phenotyping results. The modeling assumptions, model parameters, and assignments of fractional CYP3A4 metabolism were verified using results from clinical pharmacokinetics (PK) and DDI studies with ketoconazole and rifampin. The verified glasdegib and efavirenz compound files, the latter of which was available in the Simcyp simulator, were used to estimate the potential impact of efavirenz on the PK of glasdegib. PBPK modeling predicted a glasdegib area under the concentration-time curve ratio of 0.45 and maximum plasma concentration ratio of 0.75 following coadministration with efavirenz. The PBPK results, in lieu of a formal clinical study, informed the drug label, with the recommendation to double the clinical dose of glasdegib when administered in conjunction with a moderate CYP3A4 inducer, followed by a resumption of the original dose 7 days post-discontinuation.

Ketoconazole-loading strategy to improve antifungal activity and overcome cytotoxicity on human renal proximal tubular epithelial cells

Ketoconazole (KTZ), an antifungal agent used to treat localized or systemic fungal infections by inhibiting ergosterol synthesis, exhibits restricted efficacy within eukaryotic cells owing to its elevated toxicity and limited solubility in water. This study aims to improve the biological activity and overcome cytotoxic effects in the renal system of the hydrophobic KTZ by incorporating it into poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) utilizing biomaterial nano-engineering techniques. KTZ-loaded PLGA NPs (KTZ-NPs) were prepared by single emulsion solvent evaporation method and characterized by using dynamic light scattering (DLS), electrophoretic light scattering (ELS), Fourier transform-infrared (FT-IR) spectroscopy and scanning light microscopy (SEM). Particle size and zeta potential of KTZ-NPs were determined as 182.0 ± 3.27 nm and -27.4 ± 0.56 mV, respectively. Antifungal activity was analyzed with the time-kill and top agar dilution methods onCandida albicans(C. albicans) andAspergillus flavus(A. flavus). Both KTZ and KTZ-NPs caused a significant decrease inA. flavuscell growth; however, the same effect was only observed in time-killing analysis onC. albicans, indicating a methodological difference in the antifungal analysis. According to the top agar method, the MIC value of KTZ-NPs againstA. flavuswas 9.1μg ml-1, while the minimum inhibition concentration (MIC) value of KTZ was 18.2μg ml-1. The twofold increased antifungal activity indicates that nanoparticular drug delivery systems enhance the water solubility of hydrophobic drugs. In addition, KTZ-NPs were not cytotoxic on human renal proximal tubular epithelial cells (HRPTEpCs) at fungistatic concentration, thus reducing fungal colonization without cytotoxic on renal excretion system cells.

Evaluation of the inhibitory effect of azoles on pharmacokinetics of lenvatinib in rats both in vivo and in vitro by UPLC-MS/MS

BACKGROUND

Lenvatinib is a multitargeted tyrosine kinase inhibitor used in the treatment of a variety of solid tumors. This study aims to investigate the potential pharmacokinetic interactions between lenvatinib and various azoles (ketoconazole, voriconazole, isavuconazole and posaconazole) when orally administered to rats.

METHODS

A total of 30 Sprague-Dawley rats were randomly allocated into five groups and administered 20 mg/kg of ketoconazole, voriconazole, isavuconazole and 30 mg/kg of posaconazole and 0.5% CMC-Na, through gavage for a duration of 7 days prior to the commencement of the experiment. On the final day, the rats were given 10 mg/kg of lenvatinib. The blood concentration of lenvatinib was determined using UPLC-MS-MS. In vitro lenvatinib were incubated with azoles and rat liver microsomes (RLMs) or human liver microsomes (HLMs). Molecular docking was lastly used to examine the binding strength of the enzymes and ligands with Autodock Vina.

RESULTS

AUC and Cmax of lenvatinib significantly increased with each of the azoles (p < 0.05), whereas CLz/F decreased 0.83-flod, 0.41-fold (p < 0.05) and 0.72-fold (p < 0.01) in voriconazole, isavuconazole and ketoconazole in rats. The IC50 of lenvatinib with the azoles were 0.237, 1.300, 0.355 and 2.403 μM in RLMs and 0.160, 1.933, 3.622 and 1.831 μM in HLMs. Molecular docking analysis suggested that azoles exhibited a strong binding ability towards the target enzymes.

CONCLUSION

It is imperative to acknowledge the potential drug-drug interactions mediated by CYP3A4 between azoles and lenvatinib, as these interactions hold significant implications for their clinical utilization.

Antifungal susceptibility profile of yeasts isolated from the oral cavity of cats

BACKGROUND

Microorganisms living in the oral cavity play an important role in health and disease of the host. Cats are susceptible to oral infections, and it is documented that fungi in the oral cavity could impact these infections. Antifungal resistance has been increasing in recent years.

OBJECTIVES

This study was designed to identify yeast isolates from the oral cavity of healthy cats and to evaluate their antifungal susceptibility pattern.

METHODS

Oral specimens were collected from 60 cats and cultured at 37°C for 10 days. Yeasts were isolated and identified. Their antifungal susceptibility pattern was determined according to CLSI M44-A.

RESULTS

Three yeast genera were isolated, including Candida spp (55.5%), Rhodotorula spp (33.3%) and Hanseniaspora spp (11.1%). Antifungal susceptibility profiling showed that, apart from a dose-dependent effect of itraconazole, Hanseniaspora spp was susceptible to all seven drugs studied. The Candida species were susceptible to all drugs except ketoconazole (sensitivity 80%) and caspofungin (sensitivity 40%). In R. glutinis and R. minuta, 100% sensitivity was observed for amphotericin B, posaconazole, ketoconazole and voriconazole.

CONCLUSIONS

The results suggest that, in comparison with humans and other animals, cats have a different oral mycoflora in terms of species, number and diversity. However, these isolates have similar susceptibility patterns to those seen in isolates from other animals and humans. More studies should be done to further characterize the oral mycobiota of cats and its role in oral infections.

Revisiting Supersaturation of a Biopharmaceutical Classification System IIB Drug: Evaluation via a Multi-Cup Dissolution Approach and Molecular Dynamic Simulation

As a subclass of the biopharmaceutical classification system (BCS) class II, basic drugs (BCS IIB) exhibit pH-dependent solubility and tend to generate supersaturation in the gastrointestinal tract, leading to less qualified in vitro-in vivo correlation (IVIVC). This study aims to develop a physiologically based multi-cup dissolution approach to improve the evaluation of the supersaturation for a higher quality of IVIVC and preliminarily explores the molecular mechanism of supersaturation and precipitation of ketoconazole affected by Polyvinylpyrrolidone-vinyl acetate copolymer (PVPVA) and hydroxypropyl methyl-cellulose (HPMC). The concentration of ketoconazole in each cup of the dynamic gastrointestinal model (DGIM) was measured using fiber optical probes. Molecular interactions between ketoconazole and PVPVA or HPMC were simulated by Materials Studio. The results demonstrated that PVPVA and HPMC improved and maintained the supersaturation of ketoconazole. PVPVA exhibited superior precipitation inhibitory effect on ketoconazole molecule aggregation due to slightly stronger van der Waals forces as well as unique electrostatic forces, thereby further enhancing in vitro drug absorption, which correlated well with in vivo drug absorption. Compared with a conventional dissolution apparatus paddle method, the DGIM improved the mean prediction error through the IVIVC from 19.30% to 9.96%, reaching the qualification criteria. In conclusion, the physiologically based multi-cup dissolution approach enables improved evaluation of supersaturation in gastrointestinal transportation of BCS IIB drug ketoconazole, enabling screening screen precipitation inhibitors and achieving qualified IVIVC for drug formulation studies.

Treatment with the Topical Antimicrobial Peptide Omiganan in Mild-to-Moderate Facial Seborrheic Dermatitis versus Ketoconazole and Placebo: Results of a Randomized Controlled Proof-of-Concept Trial

Facial seborrheic dermatitis (SD) is an inflammatory skin disease characterized by erythematous and scaly lesions on the skin with high sebaceous gland activity. The yeast Malassezia is regarded as a key pathogenic driver in this disease, but increased Staphylococcus abundances and barrier dysfunction are implicated as well. Here, we evaluated the antimicrobial peptide omiganan as a treatment for SD since it has shown both antifungal and antibacterial activity. A randomized, patient- and evaluator-blinded trial was performed comparing the four-week, twice daily topical administration of omiganan 1.75%, the comparator ketoconazole 2.00%, and placebo in patients with mild-to-moderate facial SD. Safety was monitored, and efficacy was determined by clinical scoring complemented with imaging. Microbial profiling was performed, and barrier integrity was assessed by trans-epidermal water loss and ceramide lipidomics. Omiganan was safe and well tolerated but did not result in a significant clinical improvement of SD, nor did it affect other biomarkers, compared to the placebo. Ketoconazole significantly reduced the disease severity compared to the placebo, with reduced Malassezia abundances, increased microbial diversity, restored skin barrier function, and decreased short-chain ceramide Cer[NSc34]. No significant decreases in Staphylococcus abundances were observed compared to the placebo. Omiganan is well tolerated but not efficacious in the treatment of facial SD. Previously established antimicrobial and antifungal properties of omiganan could not be demonstrated. Our multimodal characterization of the response to ketoconazole has reaffirmed previous insights into its mechanism of action.

CYP51-mediated cholesterol biosynthesis is required for the proliferation of CD4+ T cells in Sjogren's syndrome

CYtochrome P450, family 51 (CYP51) is an important enzyme for de novo cholesterol synthesis in mammalian cells. In the present study, we found that the expression of CYP51 positively correlated with CD4+ T cell activation both in vivo and in vitro. The addition of ketoconazole, a pharmacological inhibitor of CYP51, prevented the proliferation and activation of anti-CD3/CD28-expanded mouse CD4+ T cells in a dose-dependent fashion. Liquid chromatography-tandem mass spectrometry indicated an increase in levels of lanosterol in T cells treated with ketoconazole during activation. Ketoconazole-induced blockade of the cholesterol synthesis pathway also caused Sterol regulatory element binding protein 2 (SREBP2) activation in CD4+ T cells. Additionally, ketoconazole treatment elicited an integrated stress response in T cells that up-regulated activating transcription factor 4 (ATF4) and DNA-damage inducible transcript 3 (DDIT3/CHOP) at the translational level. Furthermore, treatment with ketoconazole significantly decreased the amount of CD4+ T cells infiltrating lesions in the submandibular glands of NOD/Ltj mice. In summary, our results suggest that CYP51 plays an essential role in the proliferation and survival of CD4+ T cells, which makes ketoconazole an inhibitor of CD4+ T cell proliferation and of the SS-like autoimmune response through regulating the biosynthesis of cholesterol and inducing the integrated stress response.

ERG11 Gene Variability and Azole Susceptibility in Malassezia pachydermatis

Malassezia pachydermatis is part of the normal skin microbiota of various animal species but under certain circumstances becomes an opportunistic pathogen producing otitis and dermatitis. Commonly these Malassezia diseases are effectively treated using azoles. However, some cases of treatment failure have been reported. Alterations in the ERG11 gene have been associated with in vitro azole resistance in M. pachydermatis. In the present study, in vitro antifungal susceptibility of 89 different strains of M. pachydermatis isolated from different animal species and health status was studied. The susceptibility to fluconazole (FLZ), itraconazole (ITZ), ketoconazole and amphotericin B was tested by a disk diffusion method and 17 strains were also subjected to an ITZ E-test. Mueller-Hinton supplemented with 2% glucose and methylene blue was used as culture medium in both susceptibility assays. Multilocus sequence typing was performed in 30 selected strains using D1D2, ITS, CHS2 and β-tubulin genes. Also, ERG11 gene was sequenced. The four antifungals tested were highly effective against most of the strains. Only two strains showed no inhibition zone to antifungals and a strain showed an increased MIC to ITZ. The study of the ERG11 sequences revealed a high diversity of DNA sequences and a total of 23 amino acid substitutions, from which only two have been previously described. Also, three deleterious substitutions (A302T, G459D and G461D) previously associated with azole resistance in this yeast were recovered. A correlation between certain genotypes and ERG11 mutations was observed. Some of the ERG11 mutations recovered were correlated with a reduced susceptibility to azoles.

Identification of biomarkers and outcomes of endocrine disruption in human ovarian cortex using In Vitro Models

Endocrine disrupting chemicals (EDCs) are raising concerns about adverse effects on fertility in women. However, there is a lack of information regarding mechanisms and effects in humans. Our study aims to identify mechanisms of endocrine disruption using two EDCs, diethylstilbestrol (DES) and ketoconazole (KTZ)¹. Human ovarian cortical tissue obtained from Caesarean section patients was exposed to 10^-9 M - 10^-5 M KTZ and 10^-10 M - 10^-6 M DES in vitro for 6 days. Follicle survival and growth were studied via histology analysis and liquid-chromatography-mass spectrometry-based steroid quantification. RNA-sequencing was performed on COV434, KGN, and primary ovarian cells that were exposed for 24 h. Significantly lower unilaminar follicle densities were observed in DES 10^-10 M group, whereas low KTZ exposure reduced secondary follicle density. KTZ 10^-5 M reduced levels of pregnenolone and progesterone. RNA-sequencing revealed that 445 and 233 differentially expressed genes (false discovery rate < 0.1) altogether in DES and KTZ exposed groups. Gene set variation analysis showed that both chemicals modulated pathways that are important for folliculogenesis and steroidogenesis. We selected stearoyl-CoA desaturase (SCD) and 7-dehydrocholesterol reductase (DHCR7) for further validation. Up-regulation of both genes in response to KTZ was confirmed by qPCR and in situ RNA hybridization. Further validation with immunofluorescence focused on the expression of SCD in growing follicles in exposed ovarian tissue. In conclusion, SCD may serve as a potential novel human-relevant biomarker of EDC exposure and effects on ovaries.

Fungicidal Activity of Zinc Oxide Nanoparticles against Azole-Resistant Aspergillus flavus Isolated from Yellow and White Maize

The risk of resistance development and adverse effects on human health and the environment has increased in the last decade. Furthermore, many antifungal agents fail to inhibit the pathogenesis of azole-resistant Aspergillus flavus. In this report, we isolated and identified azole-resistant A. flavus isolates from two sources of maize (white and yellow maize). The susceptibilities of Aspergillus flavus isolates were investigated by conventional antifungals such as Terbinfine, Fluconazole, Ketoconazole, Voricazole, Amphotericin, and Nystatin. Then zinc oxide nanoparticles associated with Chlorella vulgaris, which are synthesized by using the precipitation method, were examined against isolated fungi. The results showed that twelve species of white corn were isolated out of fifty isolates, while the number of isolates from the yellow corn source was only four. Interestingly, the following antifungals have an impact effect against azole-resistant A. flavus isolates: the inhibition zones of ketoconazole, voricazole, and terbinafine were 40 mm, 20 mm, and 12 mm, respectively, while the remaining antifungal agents have no effect. Similarly, the inhibition zones of the following antifungal agents were as follows: 41 mm for Terbinfine, 13 mm for Voricazole, and 11 mm for Ketoconazole against Aspergillus flavus that was isolated from yellow corn. The physiochemical characterization of zinc oxide nanoparticles provides evidence that ZnO-NPs associate with Chlorella vulgaris and have been fabricated by the precipitation method with a diameter of 25 nm. The zinc oxide nanoparticle was then used to isolate azole-resistant A. flavus, and the results show that ZnO-NPs have an effect on azole-resistant A. flavus isolation. The inhibition zone of zinc oxide nanoparticles against A. flavus (that was isolated from white corn) was 50 mm with an MIC of 50 mg/mL, while the inhibition zone of zinc oxide nanoparticles against Azole-resistant A. flavus isolated from yellow corn was 14 nm with an MIC of 25 mg/mL, which indicated that zinc oxide nanoparticles gave a better result against Azole-resistant A. flavus isolated from maize.

Stimulatory and Inhibitory Effects of Steroid Hormones and Human Cytochrome P450 (CYP) 3A Inhibitors on Cortisol 6β-Hydroxylation Catalyzed by CYP3A Subfamilies

OBJECTIVE

The inhibitory and stimulatory effects of several compounds, including steroid hormones and azole antifungal agents, on cortisol 6β-hydroxylation activity by cytochrome P450 (CYP) 3A4, polymorphically expressed CYP3A5, and fetal CYP3A7 were compared with those on testosterone 6β-hydroxylation to clarify the catalytic properties of the predominant forms of the human CYP3A subfamily.

METHODS

6β-Hydroxylation activities of cortisol and testosterone by CYP3A4, CYP3A5, and CYP3A7 in the absence or presence of dehydroepiandrosterone (DHEA), α-naphthoflavone (ANF), ketoconazole, itraconazole, and voriconazole were measured using high-performance liquid chromatography.

RESULTS

Lower concentrations of DHEA and ANF increased cortisol 6β-hydroxylation activities catalyzed by CYP3A4 but not those catalyzed by CYP3A5 and CYP3A7. The inhibition strength of azole antifungal agents against cortisol 6β-hydroxylation catalyzed by all CYP3A subfamilies was similar to that of testosterone 6β-hydroxylation. Although the Michaelis constant (Km) increased 2-fold in the presence of 20 μM DHEA compared to that of the control, the maximal velocity (Vmax) values gradually increased with increasing DHEA. For ANF, both Km and Vmax values increased, although the Km value decreased at 2.5 μM concentrations. Ketoconazole and itraconazole competitively inhibited cortisol 6β-hydroxylation mediated by CYP3A4 with similar inhibition constants.

CONCLUSION

The inhibitory/stimulatory pattern among CYP3A subfamily members differed between cortisol and testosterone, and CYP3A4 was found to be the most sensitive in terms of inhibition by azole antifungals among the CYP3A subfamily members investigated.

In Vitro Combination of Terbinafine with Ketoconazole Against Aspergillus Species with Terbinafine High MIC Values Isolated From Otomycosis

Otomycosis is a common mycotic infection of the external auditory canal, and Aspergillus species are one of the most frequent causative agents worldwide. The limited antifungal arsenal, the high toxicity and side effects of antifungal agents, and the growing resistance to the currently available antifungals underscore the need for new therapeutic strategies. The present study aimed to evaluate the combined in vitro efficacy of terbinafine and ketoconazole against Aspergillus species with terbinafine high MIC values isolated from patients with otomycosis.84 Aspergillus species with high MIC values to terbinafine (≥ 4 µg/ml), consisting of A. flavus, A. tubingensis, A. niger, and A. terreus, were included in this study. The checkerboard microdilution method evaluated the in vitro interactions using the CLSI reference technique. Synergistic effects were observed for 66.67% (56/84) of all isolates (FICI ranging from 0.19 to 0.5). However, the interactions of terbinafine and ketoconazole exhibited indifference in 33.33% (28/84) of the isolates, and no antagonism was observed for any combination. The interaction of terbinafine and ketoconazole showed synergistic activity against Aspergillus species with high MIC values, suggesting that this is an alternative and promising approach for treating otomycosis.

Evaluation of Anti-Candida albicans Activity and Release of Ketoconazole in PMMA-G-PEG 4000 Films

Modified release systems depend on the selection of an appropriate agent capable of controlling the release of the drug, sustaining the therapeutic action over time, and/or releasing the drug at the level of a particular tissue or target organ. Polyethylene glycol 4000 (PEG 4000) is commonly employed in drug release formulations while polymethyl methacrylate (PMMA) is non-toxic and has a good solubility in organic solvents. This study aimed at the incorporation of ketoconazole in PMMA-g-PEG 4000 and its derivatives, thus evaluating its release profile and anti-Candida albicans and cytotoxic activities. Ketoconazole was characterized and incorporated into the copolymers. The ketoconazole incorporated in the copolymer and its derivatives showed an immediate release profile. All copolymers with ketoconazole showed activity against Candida albicans and were non-toxic to human cells in the entire concentration tested.

Synergistic Activity of Ketoconazole and Miconazole with Prochloraz in Inducing Oxidative Stress, GSH Depletion, Mitochondrial Dysfunction, and Apoptosis in Mouse Sertoli TM4 Cells

Triazole and imidazole fungicides represent an emerging class of pollutants with endocrine-disrupting properties. Concerning mammalian reproduction, a possible causative role of antifungal compounds in inducing toxicity has been reported, although currently, there is little evidence about potential cooperative toxic effects. Toxicant-induced oxidative stress (OS) may be an important mechanism potentially involved in male reproductive dysfunction. Thus, to clarify the molecular mechanism underlying the effects of azoles on male reproduction, the individual and combined potential of fluconazole (FCZ), prochloraz (PCZ), miconazole (MCZ), and ketoconazole (KCZ) in triggering in vitro toxicity, redox status alterations, and OS in mouse TM4 Sertoli cells (SCs) was investigated. In the present study, we demonstrate that KCZ and MCZ, alone or in synergistic combination with PCZ, strongly impair SC functions, and this event is, at least in part, ascribed to OS. In particular, azoles-induced cytotoxicity is associated with growth inhibitory effects, G0/G1 cell cycle arrest, mitochondrial dysfunction, reactive oxygen species (ROS) generation, imbalance of the superoxide dismutase (SOD) specific activity, glutathione (GSH) depletion, and apoptosis. N-acetylcysteine (NAC) inhibits ROS accumulation and rescues SCs from azole-induced apoptosis. PCZ alone exhibits only cytostatic and pro-oxidant properties, while FCZ, either individually or in combination, shows no cytotoxic effects up to 320 µM.

Cytochrome P450 Inhibition by Antimicrobials and Their Mixtures in Rainbow Trout Liver Microsomes In Vitro

Antimicrobials are ubiquitous in the environment and can bioaccumulate in fish. In the present study, we determined the half-maximal inhibitory concentrations (IC50) of 7 environmentally abundant antimicrobials (ciprofloxacin, clarithromycin, clotrimazole, erythromycin, ketoconazole, miconazole, and sulfamethoxazole) on the cytochrome P450 (CYP) system in rainbow trout (Oncorhynchus mykiss) liver microsomes, using 7-ethoxyresorufin O-deethylation (EROD, CYP1A) and 7-benzyloxy-4-trifluoromethylcoumarin O-debenzylation (BFCOD, CYP3A) as model reactions. Apart from ciprofloxacin and sulfamethoxazole, all antimicrobials inhibited either EROD or BFCOD activities or both at concentrations <500 µM. Erythromycin was the only selective and time-dependent inhibitor of BFCOD. Compared with environmental concentrations, the IC50s of individual compounds were generally high (greater than milligrams per liter); but as mixtures, the antimicrobials resulted in strong, indicatively synergistic inhibitions of both EROD and BFCOD at submicromolar (~micrograms per liter) mixture concentrations. The cumulative inhibition of the BFCOD activity was detectable even at picomolar (~nanograms per liter) mixture concentrations and potentiated over time, likely because of the strong inhibition of CYP3A by ketoconazole (IC50 = 1.7 ± 0.3 µM) and clotrimazole (IC50 = 1.2 ± 0.2 µM). The results suggest that if taken up by fish, the mixtures of these antimicrobials may result in broad CYP inactivation and increase the bioaccumulation risk of any other xenobiotic normally cleared by the hepatic CYPs even at biologically relevant concentrations. Environ Toxicol Chem 2022;41:663-676. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

In vivo comparative study of the efficacy of β-sitosterol, ketoconazole 2% and mupirocin for the treatment cutaneous leishmaniosis

Cutaneous leishmaniosis (CL) is an important parasitic disease characterized by specific skin lesion, includes the vector that cause the CL and treatment in general. The study aimed to identify the effect of three different drugs which are β-sitosterol, ketoconazole 2% and mupirocin in the treatment of cutaneous leishmaniosis. The study was conducted at Dermatological Unit of Al Hussein Teaching Hospital/Thi-Qar/Iraq from October to November 2021. The patients presented with a lesion will be involved in this study and its involved isolation of parasites from the lesion of patients and the parasite was replicated in (NNN) media then the inoculum was concentered. A total of 40 male of mice (Mus musculus) of BALB/c strain injected by parasite suspension, after the appearance of lesion, β-sitosterol, ketoconazole 2% and mupirocin was applied on a lesions daily for 2 weeks, the statistical analysis was done by SPSS program. In the current study, the β-sitosterol was most effective in the treatment of skin leishmanial lesion than the other drugs with mean is (11.9±1.449 mm) in compared with the other drugs under P-value < 0.046 with the complete recovery. β-sitosterol was highly effect on the L. tropica infections with complete recovery and no scar appearance than ketoconazole and mupirocin and can be used for treatment of the disease lesion.

The function of adrenal glands in children and adolescents during and after oncological treatment

The purpose of this work was to present the current state of knowledge on the effects of frequently used therapeutic forms, selected pharmacotherapy (including glucocorticosteroids, immune checkpoint inhibitors, mitotane, metyrapone, aminoglutetimide, etomidate, ketoconazole, fluconazole), but also radiation therapy on the functioning of the hypothalamic-pituitary-adrenal axis in children and adolescent during and after oncological treatment. The most common pediatric cancers, where complications of adrenal insufficiency occur, are presented. Moreover, current recommendations how to diagnose the function of the adrenal axis in oncological pediatric patients, as well during oncological treatment as after it, including patients treated with steroids and also patients in severe stages, are reported. The rules of the treatment of adrenal dysfunction in those patients are presented. This understanding is of key importance for oncologists and endocrinologists in the process of diagnosing, treating and developing patient health care, as well as during therapy as after it, offering safety and improving the quality of life.

[Effects of ketoconazole on physiological function of liver and testis in mice]

Objective: To investigate the effects of different doses of ketoconazole (KCZ) on the physiological functions of the liver and testis in Kunming mice. Methods: Forty male Kunming mice were randomly divided into four groups (n=10): normal group, KCZ low-dose group (30 mg/kg), medium-dose group (50 mg/kg), and high-dose group (70 mg/kg). The mice in the drug groups were injected subcutaneously (0.1 ml/10 g) with the corresponding dose of KCZ once a day, and the concentrations of KCZ in the KCZ low, middle, and high dose groups were 3 mg/ml, 5 mg/ml and 7 mg/ml respectively, and the normal group was injected with the same amount of normal saline for 3 weeks. The activities of aspartate transaminase (AST) and alanine aminotransferase (ALT) in serum, and γ-glutamyl transpeptidase (γ-GT), lactate dehydrogenase (LDH) and acid phosphatase (ACP) in testicular tissue were measured. HE staining was used to observe the pathological changes of the liver and testis. Results: Compared with the normal group, the activities of AST and ALT were increased significantly (P＜0.01), and the activities of γ-GT, ACP and LDH were decreased markedly in KCZ groups (P＜0.01). KCZ could affect the above indexes in a dose-dependent manner. HE staining showed that the hepatocytes were denatured, arranged loosely, and the cytoplasm was light in color. The lumen of the seminiferous tubules of the testis were enlarged, and the number of spermatogenic cells and sperm at all levels were decreased. Conclusion: KCZ could cause physiological function damage and pathological histological changes of the liver and testis, increase the levels of liver transaminase, reduce the activities of testicular specific enzymes of mice. Besides, the degree of damage was increased with the increase of dose.

Itraconazole inhibits nuclear delivery of extracellular vesicle cargo by disrupting the entry of late endosomes into the nucleoplasmic reticulum

Extracellular vesicles (EVs) are mediators of intercellular communication under both healthy and pathological conditions, including the induction of pro-metastatic traits, but it is not yet known how and where functional cargoes of EVs are delivered to their targets in host cell compartments. We have described that after endocytosis, EVs reach Rab7+ late endosomes and a fraction of these enter the nucleoplasmic reticulum and transport EV biomaterials to the host cell nucleoplasm. Their entry therein and docking to outer nuclear membrane occur through a tripartite complex formed by the proteins VAP-A, ORP3 and Rab7 (VOR complex). Here, we report that the antifungal compound itraconazole (ICZ), but not its main metabolite hydroxy-ICZ or ketoconazole, disrupts the binding of Rab7 to ORP3-VAP-A complexes, leading to inhibition of EV-mediated pro-metastatic morphological changes including cell migration behaviour of colon cancer cells. With novel, smaller chemical drugs, inhibition of the VOR complex was maintained, although the ICZ moieties responsible for antifungal activity and interference with intracellular cholesterol distribution were removed. Knowing that cancer cells hijack their microenvironment and that EVs derived from them determine the pre-metastatic niche, small-sized inhibitors of nuclear transfer of EV cargo into host cells could find cancer therapeutic applications, particularly in combination with direct targeting of cancer cells.

Effects of CYP3A inhibitors ketoconazole, voriconazole, and itraconazole on the pharmacokinetics of sunitinib and its main metabolite in rats

Sunitinib is a small molecule inhibitor of multiple receptor tyrosine kinases such as platelet derived growth factor receptor, vascular endothelial growth factor receptor, kit receptor and other receptors. The US Food and Drug Administration (FDA) has approved sunitinib for the treatment of advanced renal cell carcinoma and gastrointestinal stromal tumors. It has been reported that sunitinib was mainly metabolized by CYP3A but its pharmacokinetic interactions have not been revealed. In this study, we investigated whether CYP3A inhibitors (ketoconazole, voriconazole, and itraconazole) could influence the pharmacokinetics of sunitinib and its equipotent metabolite N-desethyl sunitinib in a drug-drug interaction study in Sprague Dawley (SD) rats. The results showed that ketoconazole and voriconazole significantly increased the exposure of sunitinib, decreased the exposure of N-desethyl sunitinib, and inhibited the metabolism of sunitinib in rats. However, itraconazole showed only a weak effect on pharmacokinetics and metabolism. Coadministration of sunitinib with ketoconazole and voriconazole should be avoided if possible or if not, there should be therapeutic drug monitoring of the levels of sunitinib and N-desethyl sunitinib. Therefore, drug-drug interaction should be considered when sunitinib is administered in conjunction with CYP3A inhibitors, which might lead to toxicity.

Establishment of a Novel Human Fetal Adrenal Culture Model that Supports de Novo and Manipulated Steroidogenesis

CONTEXT

Disorders affecting adrenal steroidogenesis promote an imbalance in the normally tightly controlled secretion of mineralocorticoids, glucocorticoids, and androgens. This may lead to differences/disorders of sex development in the fetus, as seen in virilized girls with congenital adrenal hyperplasia (CAH). Despite the important endocrine function of human fetal adrenals, neither normal nor dysregulated adrenal steroidogenesis is understood in detail.

OBJECTIVE

Due to significant differences in adrenal steroidogenesis between human and model species (except higher primates), we aimed to establish a human fetal adrenal model that enables examination of both de novo and manipulated adrenal steroidogenesis.

DESIGN AND SETTING

Human adrenal tissue from 54 1st trimester fetuses were cultured ex vivo as intact tissue fragments for 7 or 14 days.

MAIN OUTCOME MEASURES

Model validation included examination of postculture tissue morphology, viability, apoptosis, and quantification of steroid hormones secreted to the culture media measured by liquid chromatography-tandem mass spectrometry.

RESULTS

The culture approach maintained cell viability, preserved cell populations of all fetal adrenal zones, and recapitulated de novo adrenal steroidogenesis based on continued secretion of steroidogenic intermediates, glucocorticoids, and androgens. Adrenocorticotropic hormone and ketoconazole treatment of ex vivo cultured human fetal adrenal tissue resulted in the stimulation of steroidogenesis and inhibition of androgen secretion, respectively, demonstrating a treatment-specific response.

CONCLUSIONS

Together, these data indicate that ex vivo culture of human fetal adrenal tissue constitutes a novel approach to investigate local effects of pharmaceutical exposures or emerging therapeutic options targeting imbalanced steroidogenesis in adrenal disorders, including CAH.

Antifungal Activity of Melaleuca alternifolia Essential Oil (TTO) and Its Synergy with Itraconazole or Ketoconazole against Trichophyton rubrum

Over the past 20–30 years, Trichophyton rubrum represented the most widespread dermatophyte with a prevalence accounting for 70% of dermatophytosis. The treatment for cutaneous infections caused by Trichophyton spp. are imidazoles (ketoconazole (KTZ)) and triazoles (itraconazole (ITZ)). T. rubrum can develop resistance to azoles after prolonged exposure to subinhibitory concentrations resulting in therapeutic failures and chronic infections. These problems have stimulated the search for therapeutic alternatives, including essential oils, and their potential use in combination with conventional antifungals. The purpose of this study was to evaluate the antifungal activity of tea tree oil (TTO) (Melaleuca alternifolia essential oil) and the main components against T. rubrum and to assess whether TTO in association with KTZ/ITZ as reference drugs improves the antifungal activity of these drugs. We used a terpinen-4-ol chemotype (35.88%) TTO, and its antifungal properties were evaluated by minimum inhibitory and minimum fungicidal concentrations in accordance with the CLSI guidelines. The interaction between TTO and azoles was evaluated through the checkerboard and isobologram methods. The results demonstrated both the fungicide activity of TTO on T. rubrum and the synergism when it was used in combination with azoles. Therefore, this mixture may reduce the minimum effective dose of azole required and minimize the side effects of the therapy. Synergy activity offered a promise for combination topical treatment for superficial mycoses.

Kinetics of cytochrome P450 3A4 inhibition by heterocyclic drugs defines a general sequential multistep binding process

Cytochrome P450 (P450) 3A4 is the enzyme most involved in the metabolism of drugs and can also oxidize numerous steroids. This enzyme is also involved in one-half of pharmacokinetic drug-drug interactions, but details of the exact mechanisms of P450 3A4 inhibition are still unclear in many cases. Ketoconazole, clotrimazole, ritonavir, indinavir, and itraconazole are strong inhibitors; analysis of the kinetics of reversal of inhibition with the model substrate 7-benzoyl quinoline showed lag phases in several cases, consistent with multiple structures of P450 3A4 inhibitor complexes. Lags in the onset of inhibition were observed when inhibitors were added to P450 3A4 in 7-benzoyl quinoline O-debenzylation reactions, and similar patterns were observed for inhibition of testosterone 6β-hydroxylation by ritonavir and indinavir. Upon mixing with inhibitors, P450 3A4 showed rapid binding as judged by a spectral shift with at least partial high-spin iron character, followed by a slower conversion to a low-spin iron-nitrogen complex. The changes were best described by two intermediate complexes, one being a partial high-spin form and the second another intermediate, with half-lives of seconds. The kinetics could be modeled in a system involving initial loose binding of inhibitor, followed by a slow step leading to a tighter complex on a multisecond time scale. Although some more complex possibilities cannot be dismissed, these results describe a system in which conformationally distinct forms of P450 3A4 bind inhibitors rapidly and two distinct P450-inhibitor complexes exist en route to the final enzyme-inhibitor complex with full inhibitory activity.

Aggressive Cushing's Disease: Molecular Pathology and Its Therapeutic Approach

Cushing's disease is a syndromic pathological condition caused by adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas (ACTHomas) mediated by hypercortisolemia. It may have a severe clinical course, including infection, psychiatric disorders, hypercoagulability, and metabolic abnormalities, despite the generally small, nonaggressive nature of the tumors. Up to 20% of ACTHomas show aggressive behavior, which is related to poor surgical outcomes, postsurgical recurrence, serious clinical course, and high mortality. Although several gene variants have been identified in both germline and somatic changes in Cushing's disease, the pathophysiology of aggressive ACTHomas is poorly understood. In this review, we focused on the aggressiveness of ACTHomas, its pathology, the current status of medical therapy, and future prospects. Crooke's cell adenoma (CCA), Nelson syndrome, and corticotroph pituitary carcinoma are representative refractory pituitary tumors that secrete superphysiological ACTH. Although clinically asymptomatic, silent corticotroph adenoma is an aggressive ACTH-producing pituitary adenoma. In this review, we summarize the current understanding of the pathophysiology of aggressive ACTHomas, including these tumors, from a molecular point of view based on genetic, pathological, and experimental evidence. The treatment of aggressive ACTHomas is clinically challenging and usually resistant to standard treatment, including surgery, radiotherapy, and established medical therapy (e.g., pasireotide and cabergoline). Temozolomide is the most prescribed pharmaceutical treatment for these tumors. Reports have shown that several treatments for patients with refractory ACTHomas include chemotherapy, such as cyclohexyl-chloroethyl-nitrosourea combined with 5-fluorouracil, or targeted therapies against several molecules including vascular endothelial growth factor receptor, cytotoxic T lymphocyte antigen 4, programmed cell death protein 1 (PD-1), and ligand for PD-1. Genetic and experimental evidence indicates that some possible therapeutic candidates are expected, such as epidermal growth factor receptor tyrosine kinase inhibitor, cyclin-dependent kinase inhibitor, and BRAF inhibitor. The development of novel treatment options for aggressive ACTHomas is an emerging task.

In vitro and in vivo human metabolism and pharmacokinetics of S- and R-praziquantel

Racemic praziquantel (PZQ) is the drug of choice for the treatment of schistosomiasis. R-Praziquantel (R-PZQ) has been shown as the therapeutic form, whereas S-PZQ is less efficacious and responsible for the bitter taste of the tablet. This study aimed at investigating the metabolism of R- and S-PZQ as this could have implications on efficacy and safety of racemate and R-PZQ specific formulations under development. In vitro CYP reaction phenotyping assay using 10 recombinant CYP (rCYP) isoenzymes showed hepatic CYP1A2, 2C19, 2D6, 3A4, and 3A5 were the major enzymes involved in metabolism of PZQ. Enzyme kinetic studies were performed by substrate depletion and metabolite formation methods, by incubating PZQ and its R- or S-enantiomers in human liver microsomes (HLM) and the rCYP enzymes. The effect of selective CYP inhibitors on PZQ metabolism was assessed in HLM. CYP1A2, 2C19, and 3A4 exhibited different catalytic activity toward PZQ, R- and S-enantiomers. Metabolism of R-PZQ was mainly catalyzed by CYP1A2 and CYP2C19, whereas metabolism of S-PZQ was mainly by CYP2C19 and CYP3A4. Based on metabolic CLint obtained through formation of hydroxylated metabolites, CYP3A4 was estimated to contribute 89.88% to metabolism of S-PZQ using SIMCYP® IVIVE prediction. Reanalysis of samples from a human PZQ-ketoconazole (KTZ) drug-drug interaction pharmacokinetic study confirmed these findings in that KTZ, a potent inhibitor of CYP3A, selectively increased area under the curve of S-PZQ by 68% and that of R-PZQ by just 9%. Knowledge of enantioselective metabolism will enable better understanding of variable efficacy of PZQ in patients and the R-PZQ formulation under development.

Dechlorination and demethylation of ochratoxin A enhance blocking activity of PXR activation, suppress PXR expression and reduce cytotoxicity

The pregnane X receptor (PXR) has been established to induce chemoresistance and metabolic diseases. Ochratoxin A (OTA), a mycotoxin, decreases the expression of PXR protein in human primary hepatocytes. OTA is chlorinated and has a methylated lactone ring. Both structures are associated with OTA toxicity. The study was to test the hypothesis that structural modifications differentially impact PXR blocking activity over cytotoxicity. To test this hypothesis, OTA-M and OTA-Cl/M were synthesized. OTA-M lacked the methyl group of the lactone-ring, whereas OTA-Cl/M had neither the methyl group nor the chlorine atom. The blocking activity of PXR activation was determined in a stable cell line, harboring both PXR (coding sequence) and its luciferase element reporter. OTA-Cl/M showed the highest blocking activity, followed by OTA-M and OTA. OTA-Cl/M was 60 times as potent as the common PXR blocker ketoconazole based on calculated IC₅₀ values. OTA-Cl/M decreased by 90 % the expression of PXR protein and was the least cytotoxic among the tested compounds. Molecular docking identified that OTA and its derivatives interacted with different sets of residues in PXR, providing a molecular basis for selectivity. Excessive activation of PXR has been implicated in chemoresistance and metabolic diseases. Downregulation of PXR protein expression likely delivers an effective mechanism against structurally diverse PXR agonists.

Canine sporotrichosis: polyphasic taxonomy and antifungal susceptibility profiles of Sporothrix species in an endemic area in Brazil

Sporotrichosis, a mycosis caused by pathogenic species of the genus Sporothrix, affects diverse species of mammals. Until 2007, Sporothrix schenckii was considered the unique etiologic agent of sporotrichosis. Canine sporotrichosis is a poorly reported disease, and the majority of cases are from Rio de Janeiro, Brazil. There are scarce studies on the characterization of canine isolates of Sporothrix schenckii complex, as well as few antifungal susceptibility data available. The aim of this study was to characterize the clinical isolates of Sporothrix from dogs from Brazil at species level and evaluate their antifungal susceptibility profile. Polyphasic taxonomy was used to characterization at species level (morphological, phenotypical characteristics, and molecular identification). Antifungal susceptibility profiles (amphotericin B, itraconazole, ketoconazole, posaconazole, and terbinafine) were determined using the Clinical and Laboratory Standards Institute broth microdilution method (M38-A2). According to phenotypic identification and molecular analysis, 46 isolates included in this study were identified as S. brasiliensis and one as S. schenckii. Amphotericin B presented the highest minimum inhibitory concentration values, and the other drugs showed effective in vitro antifungal activity. This is the first report of S. schenckii in dogs from Brazil, since S. brasiliensis is the only species that has been described in canine isolates from Rio de Janeiro to date. Nevertheless, no differences were observed in the antifungal susceptibility profiles between the S. brasiliensis and S. schenckii isolates, and it is important to continuously study new canine clinical isolates from Rio de Janeiro, Brazil.

Comparative evaluation of E-test and CLSI methods for Itraconazole, Fluconazole and Ketoconazole susceptibilities of Microsporum canis strains

The incidence of resistance to antifungal agents for dermatophytes is increasing, but most of the methods currently available to test the antifungal susceptibility of Microsporum canis still require standardization. The aims of this study were: (i) to evaluate the antifungal susceptibility of M. canis strains recovered from animals to ketoconazole (KTZ), fluconazole (FLZ) and itraconazole (ITZ) using a modified CLSI broth microdilution (CLSI M38-A2-BMD) and the E-test® protocols and (ii) to estimate the agreement between the methods. Tentative azole epidemiological cutoff values (ECVs) were also proposed in order to interpret the results of in vitro susceptibility tests and to establish the agreement between the E-test and CLSI BMD methods. A total of forty clinical M. canis strains from animals with skin lesions were tested, and the essential (EA) and categorical agreement (CA) between the two methods were determined. KTZ displayed the lowest MIC values, while ITZ and FLZ the highest. The ECV for KTZ and ITZ were 4 μg/ml, while those of FLZ was 64 μg/ml. Based on ECVs, about 88% of M. canis strains were susceptible to all azoles being a cross-resistance with ITZ-FLZ registered for one strain. A total of five M. canis strains showed MIC > ECV for FLZ using CLSI, while one strain showed MIC > ECV for ITZ using both tests. KTZ, ITZ and FLZ showed EA ranging from 92.5 to 95%, for all azoles and CA > 97% except for FLZ (87.5%). The good CA between the E-test and the CLSI BMD provides evidence of the reliability of the former method to test the antifungal susceptibility of M. canis for ITZ and KTZ and not for FLZ.

Proposal of a Safe and Effective Study Design for CYP3A-Mediated Drug-Drug Interactions

Numerous drug-drug interaction (DDI) trials have to be conducted in healthy volunteers based on current regulatory guidelines. Because the worst-case scenario of strong cytochrome P450 (CYP) inhibitors has to be tested, the results and their validity have to be balanced with the risk to volunteer safety. The use of ketoconazole in clinical DDI studies has been discouraged by regulatory agencies due to an alleged risk of liver injury. In order to reduce the risk to healthy volunteers, we carried out a study with single-day exposure to each of 6 perpetrator azole fungistatic drugs. They were evaluated regarding their CYP3A inhibition using microdosed midazolam and a limited sampling strategy. Ratios of areas under the concentration-time curves ranged from 1.93 with isavuconazole to 8.42 with ketoconazole. The highest number of adverse events occurred with voriconazole, followed by ketoconazole; 2 dropouts occurred due to adverse events following itraconazole administration. Literature data on adverse events of azole fungistatic drugs in DDI trials are rare and inconclusive. Only in recent years with the newer drugs are they more precise and reliable. It can be concluded that the duration of preexposure of perpetrator drugs can be reduced to 1 hour before administration of the victim drug. This still can be sufficient to achieve the scientific objectives of the trial with the lowest possible risk.

Comparison of in vitro antifungal activity of novel triazoles with available antifungal agents against dermatophyte species caused tinea pedis

OBJECTIVE

Dermatophytes are a group of keratinophilic fungi that invade and infect the keratinized tissues and cause dermatophytosis. We investigated effectiveness of novel triazole (luliconazole and lanaconazole) in comparison with available antifungal agents against dermatophyte species isolated from patients with tinea pedis.

MATERIAL AND METHODS

A total of 60 dermatophytes species were isolated from the patients with tinea pedis. Identification of species was done by DNA sequencing of the ITS1-5.8S rDNA-ITS2 rDNA region. In vitro antifungal susceptibility testing with luliconazole and lanaconazole and available antifungal agent was done in accordance with the Clinical and Laboratory Standards Institute, M38-A2 document.

RESULTS

In all investigated isolates, luliconazole had the lowest minimum inhibitory concentration (MIC) (MIC range=0.0005-0.004μg/mL), while fluconazole (MIC range=0.4-64μg/mL) had the highest MICs. Geometric mean MIC was the lowest for luliconazole (0.0008μg/mL), followed by lanoconazole (0.003μg/mL), terbinafine (0.019μg/mL), itraconazole (0.085 μg/mL), ketoconazole (0.089μg/mL), econazole (0.097μg/mL), griseofulvin (0.351 μg/mL), voriconazole (0.583μg/mL) and fluconazole (11.58μg/mL).

CONCLUSION

The novel triazoles showed potent activity against dermatophytes and promising candidates for the treatment of tinea pedis caused by Trichophyton and Epidermophyton species. However, further studies are warranted to determine the clinical implications of these investigations.

Identification and Antifungal Activity Profile of Candida Species Isolated from Patients with Pemphigus Vulgaris with Oral Lesions

Pemphigus vulgaris is an autoimmune disease that mostly affects the mucosa and oral cavity. Candida species can invade the mucosal lesions of these patients and cause diseases. The aim of this study was to identify the fungal agents isolated from mucosal lesions and evaluate antifungal activity profile against the isolates. A total of 25 patients with pemphigus vulgaris with active oral lesions and 25 healthy people serving as a control group were included in this study. Identification of the fungal isolates was performed based on conventional methods and DNA sequence analysis of the internal transcribed spacer (ITS) rDNA gene region. The sequence results were deposited in the NCBI database using the Basic Local Alignment Search Tool. Antifungal activity of fluconazole, itraconazole, ketoconazole, posaconazole, econazole, and amphotericin B against the isolates were evaluated based on the CLSI M-44 A protocol. Oral candidiasis was detected in 20% of the patients. Candida species isolated from oral lesions of patients with pemphigus were identified as Candida albicans 22/25, Candida glabrata 2/25, and Candida dubliniensis 1/25. All of the isolates were sensitive to amphotericin and econazole, 96% to fluconazole and posaconazole, and 92% to ketoconazole and itraconazole. One patient showed a profile resistant to fluconazole, posaconazole, and ketoconazole, simultaneously. Ninety six percent of control group isolates were sensitive to six antifungals. Candida albicans was the most prevalent species isolated from oral lesions of patients with pemphigus vulgaris and the control group. Amphotericin B and econazole were the most effective antifungals against the isolates.

Spinal cytochrome P450c17 plays a key role in the development of neuropathic mechanical allodynia: Involvement of astrocyte sigma-1 receptors

While evidence indicates that sigma-1 receptors (Sig-1Rs) play an important role in the induction of peripheral neuropathic pain, there is limited understanding of the role that the neurosteroidogenic enzymes, which produce Sig-1R endogenous ligands, play during the development of neuropathic pain. We examined whether sciatic nerve injury upregulates the neurosteroidogenic enzymes, cytochrome P450c17 and 3β-hydroxysteroid dehydrogenase (3β-HSD), which modulate the expression and/or activation of Sig-1Rs leading to the development of peripheral neuropathic pain. Chronic constriction injury (CCI) of the sciatic nerve induced a significant increase in the expression of P450c17, but not 3β-HSD, in the ipsilateral lumbar spinal cord dorsal horn at postoperative day 3. Intrathecal administration of the P450c17 inhibitor, ketoconazole during the induction phase of neuropathic pain (day 0 to day 3 post-surgery) significantly reduced the development of mechanical allodynia and thermal hyperalgesia in the ipsilateral hind paw. However, administration of the 3β-HSD inhibitor, trilostane had no effect on the development of neuropathic pain. Sciatic nerve injury increased astrocyte Sig-1R expression as well as dissociation of Sig-1Rs from BiP in the spinal cord. These increases were suppressed by administration of ketoconazole, but not by administration of trilostane. Co-administration of the Sig-1R agonist, PRE084 restored the development of mechanical allodynia originally suppressed by the ketoconazole administration. However, ketoconazole-induced inhibition of thermal hyperalgesia was not affected by co-administration of PRE084. Collectively these results demonstrate that early activation of P450c17 modulates the expression and activation of astrocyte Sig-1Rs, ultimately contributing to the development of mechanical allodynia induced by peripheral nerve injury.

Hepatoprotective effect of ketoconazole in chronic liver injury model

Ketoconazole is a first orally available anti-fungal drug which has been reported as a potent inhibitor of human cytochrome P-450. The present study was designed to examine the heptoprotective effect of ketoconazole in both in vitro and in vivo liver injury models. Hepatocyte injury was induced by 8mM CCl4 while hepatic fibrosis model was established by injecting 1 ml/kg CCl4 followed by treatment with ketoconazole. Effect of ketoconazole treatment on injured hepatocytes was determined by lactate dehydrogenase release and trypan blue assay. Analysis of ketoconazole treatment and prevention on liver fibrosis was assessed by sirius red staining, masson trichome staining, PCR and liver function tests for bilirubin and alanine transaminase (ALAT).A significant reduction (P<0.05) in LDH release and reduced number of dead cells was observed in hepatocytes treated with ketoconazole. Sirus red and masson trichome stainings showed reduced levels of collagen in both treated and preventive groups and down regulation of alpha smooth muscle actin was observed with up-regulations of MMP-2, CK-8 and CK-18. Hepatic functional assessment demonstrated reduced serum levels of bilirubin and ALAT. Treatment of fibrotic liver with ketoconazole improves hepatic microenvironment and enhanced reduction of liver injury after fibrosis. Cytochrome P-450 inhibitors seems a favored therapeutic option in attenuation of liver fibrosis.

Enabling Heterologous Synthesis of Lupulones in the Yeast Saccharomyces cerevisiae

Lupulones, naturally produced by glandular trichomes of hop (Humulus lupulus), are prenylated phloroglucinol derivatives that contribute the bitter flavor of beer and demonstrate antimicrobial and anticancer activities. It is appealing to develop microbial cell factories such that lupulones may be produced via fermentation technology in lieu of extraction from limited plant resources. In this study, the yeast Saccharomyces cerevisiae transformants harboring a synthetic lupulone pathway that consisted of five genes from hop were constructed. The transformants accumulated several precursors but failed to accumulate lupulones. Overexpression of 3-hydroxy-3-methyl glutaryl co-enzyme A reductase, the key enzyme in precursor formation in the mevalonate pathway, also failed to achieve a detectable level of lupulones. To decrease the consumption of the precursors, the ergosterol biosynthesis pathway was chemically downregulated by a small molecule ketoconazole, leading to successful production of lupulones. Our study demonstrated a combination of molecular biology and chemical biology to regulate the metabolism for heterologous production of lupulones. The strategy may be valuable for future engineering microbial process for other prenylated natural products.

Synthesis and Antifungal Potential of Some Novel Benzimidazole-1,3,4-Oxadiazole Compounds

Discovery of novel anticandidal agents with clarified mechanisms of action, could be a rationalist approach against diverse pathogenic fungal strains due to the rise of resistance to existing drugs. In support to this hypothesis, in this paper, a series of benzimidazole-oxadiazole compounds were synthesized and subjected to antifungal activity evaluation. In vitro activity assays indicated that some of the compounds exhibited moderate to potent antifungal activities against tested Candida species when compared positive control amphotericin B and ketoconazole. The most active compounds 4h and 4p were evaluated in terms of inhibitory activity upon ergosterol biosynthesis by an LC-MS-MS method and it was determined that they inhibited ergosterol synthesis concentration dependently. Docking studies examining interactions between most active compounds and lanosterol 14-α-demethylase also supported the in vitro results.

Comparative Studies of Steroidogenesis Inhibitors (Econazole, Ketoconazole) on Human Breast Cancer MCF-7 Cell Proliferation by Growth Experiments, Thymidine Incorporation and Flow Cytometric DNA Analysis

The effects of aminoglutethimide, econazole and ketoconazole on human breast cancer cells in culture were compared with those of tamoxifen using four methods (growth experiments, thymidine incorporation, monoparameter and bivariate DNA content flow cytometry analysis). Aminoglutethimide (1 nM-10 microM) had no effect on cell proliferation after 8 days of treatment and did not decrease thymidine tritiated incorporation during logarithmic phase. Even at 20 microM, similar results were obtained with flow cytometry. Econazole and ketoconazole (1 nM-1 microM) decreased MCF-7 cell proliferation in a time- and dose-dependent fashion. They also decreased tritiated thymidine incorporation. By using flow cytometry and a monoclonal antibody against bromodeoxyuridine, we showed an accumulation of MCF-7 cells treated by imidazoles derivatives in G0-G1 phase of the cell cycle.

Improvement of the chemical inhibition phenotyping assay by cross-reactivity correction

BACKGROUND

The fraction of an absorbed drug metabolized by the different hepatic cytochrome P450 (CYP) enzymes, relative to total hepatic CYP metabolism (fmCYP), can be estimated by measuring the inhibitory effects of presumably selective CYP inhibitors on the intrinsic metabolic clearance of a drug using human liver microsomes. However, the chemical inhibition data are often affected by cross-reactivities of the chemical inhibitors used in this assay.

METHODS

To overcome this drawback, the cross-reactivities exhibited by six chemical inhibitors (furafylline, montelukast, sulfaphenazole, ticlopidine, quinidine and ketoconazole) were quantified using specific CYP enzyme marker reactions. The determined cross-reactivities were used to correct the in vitro fmCYPs of nine marketed drugs. The corrected values were compared with reference data obtained by physiologically based pharmacokinetics simulation using the software SimCYP.

RESULTS

Uncorrected in vitro fmCYPs of the nine drugs showed poor linear correlation with their reference data (R2=0.443). Correction by factoring in inhibitor cross-reactivities significantly improved the correlation (R2=0.736).

CONCLUSIONS

Correcting in vitro chemical inhibition results for cross-reactivities appear to offer a straightforward and easily adoptable approach to provide improved fmCYP data for a drug.

A polymorphism in the CYP17A1 gene influences the therapeutic response to steroidogenesis inhibitors in Cushing's syndrome

CONTEXT

Steroidogenesis inhibitors, such as ketoconazole (KTZ) and metyrapone (MTP), are used to lower hypercortisolism in patients with Cushing's syndrome (CS). Cortisol normalization is not reached in all patients taking these medications.

OBJECTIVE

To test the hypothesis that variants in genes affecting steroidogenesis contribute to different responses to KTZ and/or MTP in patients with CS.

PATIENTS AND METHODS

Fifty-four CS patients (46 women; mean [±SD] age, 39.7±12.7; 83% with Cushing's disease [CD] and 17% with an adrenal adenoma) preoperatively treated with KTZ (20%), MTP (37%) or a combination of both (43%). Thirty-nine of these (72%) were described in a previous study investigating the outcome of preoperative treatment with KTZ or MTP in CS patients. Following single-nucleotide polymorphisms (SNPs) were analysed: rs6410 (CYP11B1 gene), rs1799998 and rs4546 (CYP11B2 gene), and rs6163 (CYP17A1 gene). The associations between SNPs and cortisol levels at the end of medical treatment were evaluated.

RESULTS

Normalization of urinary free cortisol (UFC) was achieved in 50% of patients after 5 months of treatment. Patients carrying the CC genotype of SNP rs6163 were more likely to be controlled than AC/AA (OR 0.25 [95%CI, 0.075-0.88]; P=.031). When only patients reaching eucortisolism after medical treatment were analysed, median interquartile range (IQR) duration of treatment was shorter in patients carrying the CC genotype of SNP rs6163 as compared to AA/AC carriers (4 [4.57] months vs 5.2 [6.1] months; P=.026).

CONCLUSIONS

A polymorphism in the CYP17A1 gene was associated with the response to steroidogenesis inhibitors in CS. Genetic differences in the steroidogenic enzymes might account for inter-individual variations in the responsiveness to adrenal-blocking agents.

Regulation of hepatic abcb4 and cyp3a65 gene expression and multidrug/multixenobiotic resistance (MDR/MXR) functional activity in the model teleost, Danio rerio (zebrafish)

Multidrug/multixenobiotic resistance (MDR/MXR) confers resistance to a diverse range of potentially toxic pharmaceuticals and environmental contaminants through a cellular response that involves the coordinated induction and activity of the ATP-binding cassette (ABC) transporter P-glycoprotein (P-gp) and the Phase I metabolizing enzyme cytochrome P450 3A (CYP3A). In mammals, ligand-mediated pregnane X receptor (PXR) transcriptional activity regulates the induction of P-gp and CYP3A; however, this mechanism has not been well-characterized in piscine species. Zebrafish (Danio rerio) treated with the Pxr agonist pregnenolone 16α-carbonitrile (PCN) showed decreased P-gp (zebrafish Abcb4) and CYP3A (zebrafish Cyp3a65) mRNA levels after 48h exposure; however, treatment with PCN also resulted in increased hepatic MDR/MXR functional activity (i.e. increased Rhodamine 123 efflux) in vivo. Consistent with mammalian-like MDR/MXR regulated by PXR, the PCN-mediated modulation of hepatic Abcb4 and Cyp3a65 mRNA levels and MDR/MXR functional activity was attenuated by co-treatment with PCN and the mammalian PXR antagonist, ketoconazole (KTC). These results provide evidence that zebrafish Pxr may play a role in MDR/MXR through transcriptional regulation of abcb4 and cyp3a65 gene expression.

Copper nanoflowers as effective antifungal agents for plant pathogenic fungi

Flower-shaped copper nanoparticles were synthesised by a green and ecofriendly chemical reduction approach using copper sulphate and cytyltrimethal ammonium bromide. The UV-vis spectrophotometer analysis showed maximum absorption at about 552 nm, which is specifically reported for copper nanoparticles. The crystal lattice structure of copper nanoflowers was confirmed by X-ray diffraction analysis. Further, the transmission electron microscopic studies revealed the flower shape copper nanoparticles in the size range of 100-500 nm. The stability of thus synthesised copper nanoflowers was assessed by zeta potential analysis, which was found to be 35 mV indicating the most stable nature of nanoflowers. The antifungal activity of these copper nanoflowers was evaluated by Kirby-Bauer disk diffusion method against selected common plant pathogenic fungi. It was found that the chemosynthesised copper nanoflowers demonstrated significant inhibitory activity against the plant pathogenic Aspergillus niger, Fusarium moniliforme, F. culmorum, F. oxysporum and F. tricinctum. The maximum antifungal activity was shown against A. niger followed by F. moniliforme, F. oxysporum and F. tricinctum, whereas the minimum activity was reported against F. culmorum. Similarly, the effect of the copper nanoflowers was also evaluated in combination with commercial antifungal agent (ketoconazole), which demonstrated the enhanced activity of antifungal agent.

In vitro additive interaction between ketoconazole and antimony against intramacrophage Leishmania (Leishmania) amazonensis amastigotes

Leishmaniasis is a group of diseases caused by protozoa of Leishmania genus. The currently available treatments for this disease are expensive, present high toxicity and are associated to difficulties of healing and parasite resistance. Therefore, the development of strategies for leishmaniasis treatment is indispensable and includes reposition of existing drugs, as well as drug combination therapy. The aim of this study was to assess the nature of ketoconazole and antimony association on the cytotoxic effect against Leishmania (Leishmania) amazonensis amastigotes. The calculated mean sum of fractional 50% inhibitory concentration (x¯ΣFIC₅₀) was 2.54 and 1.43 for free and intracellular amastigotes, respectively, values that suggest an additive interaction between ketoconazole and antimony concerning to Leishmania toxicity only in the intramacrophage parasite form. Despite the clinical efficacy of ketoconazole-antimony combination has been shown in the literature, our study is the first to describe the nature of ketoconazole-antimony interaction against L. (L.) amazonensis amastigotes. Moreover, our results point out the need for future in vivo studies to confirm the nature of ketoconazole-antimony interaction and also to determine possible effective dosage regimens related to ketoconazole administration in association with the optimal lower dose of antimony.

Candidiasis: Prevalence and resistance profiling in a tertiary care hospital of Pakistan

OBJECTIVE

To determine Candida colonisation/infection in renal transplant patients and to determine the resistance pattern against antifungal drugs.

METHODS

This prospective, observational study was conducted at Al-Sayyed Hospital, Rawalpindi, Pakistan, from January to October 2014, in collaboration with the Microbiology and Public Health Laboratory's, Islamabad campus..The clinical specimens investigated included respiratory tract secretions, blood, urine, high vaginal swab, skin scrapings, and plastic devices samples.

RESULTS

Of the 7,850 samples, 164(2.08%) were positive for Candida. Candida albicans were most prevalent as they were found in 114(69%) samples. Besides, 56(34%) of the positive samples were resistant to one or more antifungal agents. Highest resistance was obtained against fluconazole. We found only 5(3.04%) positive samples of Candida glabrata; of them, 3(60%)were resistant. In case of Candida spp, 27(48%) resistance was observed. In Candida albicans, 23(41%) of the samples were found to be resistant. Most of the Candida isolates was recovered from bronchial alveolar lavage.

CONCLUSIONS

Although Candida albicans remained the main responsible species for Candida infections, but non-albican Candida species are also emerging.

Effect of ketoconazole, a strong CYP3A inhibitor, on the pharmacokinetics of venetoclax, a BCL-2 inhibitor, in patients with non-Hodgkin lymphoma

AIMS

To examine the effect of a strong cytochrome P450 (CYP) 3A inhibitor, ketoconazole, on the pharmacokinetics, safety and tolerability of venetoclax.

METHODS

Twelve patients with non-Hodgkin lymphoma (NHL) were enrolled in this Phase 1, open-label, fixed-sequence study. Patients received a single 50 mg dose of venetoclax orally on Day 1 and Day 8, and a 400 mg once daily dose of ketoconazole on Days 5-11. Blood samples were collected predose and up to 96 h after each venetoclax dose on Day 1 and Day 8.

RESULTS

Eleven patients had evaluable pharmacokinetic data and were therefore included in the statistical analyses. Compared to administration of a single 50 mg dose of venetoclax alone, ketoconazole increased the venetoclax mean maximum observed plasma concentration (Cmax ) and area under the plasma concentration-time curve from time 0 to infinity (AUC∞ ) by 2.3-fold (90% confidence interval [CI]: 2.0-2.7) and 6.4-fold (90% CI: 4.5-9.2; range: 2- to 12-fold), respectively.

CONCLUSIONS

Coadministration of venetoclax with multiple doses of ketoconazole resulted in a significant increase of venetoclax exposures, strongly suggesting that CYP3A plays a major role in elimination of venetoclax in patients. These results suggest the need to avoid concomitant use with strong and moderate inhibitors or inducers of CYP3A during the venetoclax ramp-up phase in chronic lymphocytic leukaemia (CLL) patients. For patients who have completed the ramp-up phase, a modification in venetoclax dose for use with strong and moderate inhibitors or inducers of CYP3A is recommended.

In Vitro Biotransformation of Two Human CYP3A Probe Substrates and Their Inhibition during Early Zebrafish Development

At present, the zebrafish embryo is increasingly used as an alternative animal model to screen for developmental toxicity after exposure to xenobiotics. Since zebrafish embryos depend on their own drug-metabolizing capacity, knowledge of their intrinsic biotransformation is pivotal in order to correctly interpret the outcome of teratogenicity assays. Therefore, the aim of this in vitro study was to assess the activity of cytochrome P450 (CYP)—a group of drug-metabolizing enzymes—in microsomes from whole zebrafish embryos (ZEM) of 5, 24, 48, 72, 96 and 120 h post-fertilization (hpf) by means of a mammalian CYP substrate, i.e., benzyloxy-methyl-resorufin (BOMR). The same CYP activity assays were performed in adult zebrafish liver microsomes (ZLM) to serve as a reference for the embryos. In addition, activity assays with the human CYP3A4-specific Luciferin isopropyl acetal (Luciferin-IPA) as well as inhibition studies with ketoconazole and CYP3cide were carried out to identify CYP activity in ZLM. In the present study, biotransformation of BOMR was detected at 72 and 96 hpf; however, metabolite formation was low compared with ZLM. Furthermore, Luciferin-IPA was not metabolized by the zebrafish. In conclusion, the capacity of intrinsic biotransformation in zebrafish embryos appears to be lacking during a major part of organogenesis.

Enhanced effect in combination of curcumin- and ketoconazole-loaded methoxy poly (ethylene glycol)-poly (ε-caprolactone) micelles

In order to enhance water-solubility and realize controlled release while keeping synergistic effects of ketoconazole and curcumin, drug-loaded methoxy poly (ethylene glycol)-b-poly (ε-caprolactone) micelles were prepared through thin membrane hydration method. Transmission electric microscopy and dynamitic light scattering characterization revealed the formation of ketoconazole- and curcumin-loaded micelles with an average size of 44.70nm and 39.56nm, respectively. The drug-loaded micelles endowed the two drugs' slow controlled release with water-solubility enhanced to 85 and 82000 folds higher than the corresponding raw drugs, respectively. In vitro antifungal activity test, chequerboard test and inhibition zone test indicated that efficacy of ketoconazole-loaded micelles was improved by introduction of curcumin-loaded micelles with a low fractional inhibitory concentration index (0.073). Biofilm formation inhibition assay also demonstrated that participation of curcumin-loaded micelles obviously strengthened the inhibition of fungal biofilms formation induced by ketoconazole-loaded micelles. The high synergistic activity of combinations is encouraging and the MPEG-PCL micelle is a potential drug delivery system for the combination of ketoconazole and curcumin.

Physiologically-Based Pharmacokinetic Modeling of Macitentan: Prediction of Drug-Drug Interactions

INTRODUCTION

Macitentan is a novel dual endothelin receptor antagonist for the treatment of pulmonary arterial hypertension (PAH). It is metabolized by cytochrome P450 (CYP) enzymes, mainly CYP3A4, to its active metabolite ACT-132577.

METHODS

A physiological-based pharmacokinetic (PBPK) model was developed by combining observations from clinical studies and physicochemical parameters as well as absorption, distribution, metabolism and excretion parameters determined in vitro.

RESULTS

The model predicted the observed pharmacokinetics of macitentan and its active metabolite ACT-132577 after single and multiple dosing. It performed well in recovering the observed effect of the CYP3A4 inhibitors ketoconazole and cyclosporine, and the CYP3A4 inducer rifampicin, as well as in predicting interactions with S-warfarin and sildenafil. The model was robust enough to allow prospective predictions of macitentan-drug combinations not studied, including an alternative dosing regimen of ketoconazole and nine other CYP3A4-interacting drugs. Among these were the HIV drugs ritonavir and saquinavir, which were included because HIV infection is a known risk factor for the development of PAH.

CONCLUSION

This example of the application of PBPK modeling to predict drug-drug interactions was used to support the labeling of macitentan (Opsumit).