Impurities contained in antifungal drug ketoconazole are potent activators of human aryl hydrocarbon receptor

Ligands and agonists of the aryl hydrocarbon receptor AhR: Facts and myths

The aryl hydrocarbon receptor (AhR) belongs to the essential helix-loop-helix transcription factors family. This receptor has a central role in determining host physiology and a variety of pathophysiologies ranging from inflammation and metabolism to cancer. AhR is a ligand-driven receptor with intricate pharmacology of activation depending on the type and quantity of ligand present. Therefore, a better understanding of AhR ligands per se is critical to move the field forward. In this minireview, we clarify some facts and myths about AhR ligands and how further studies could shed light on the true nature of AhR activation by these ligands. The review covers select chemical classes and explores parameters that qualify them as true receptor ligands.

Toxicological effects caused by environmental relevant concentrations of ketoconazole in Chironomus sancticaroli (Diptera, Chironomidae) larvae evaluated by oxidative stress biomarkers

Ketoconazole (KTZ), a broad-spectrum fungicidal drug, has been a significant problem in recent decades due to its toxic action on non-target aquatic organisms. Thus, the present study aimed to evaluate determine the effects that environmental relevant concentration of the commercial formulation of KTZ can exert on benthic macroinvertebrates, more specifically on larvae of the insect Chironomus sancticaroli. Acute toxicity tests with KTZ indicated lethal concentration (LC₅₀) of 9.9 μg/L. Analyses of prolonged exposure to KTZ (chronic toxicity) indicated an increase in the rate of mentum deformity by approximately 3 times at concentrations of 0.6 and 2.4 μg/L. All biomarkers analyzed showed an increase after exposure to KTZ (0.6 and 2.4 μg/L), with average values of 115 % for superoxide dismutase (SOD), 63 % for catalase (CAT), 111 % for glutathione S-transferase (GST) and 59 % for malonaldehyde (MDA) in C. sancticaroli larvae. Thus, the toxic effects on survival, development (length and weight), mentum and redox responses caused by commercial KTZ in low concentrations were observed on C. sancticaroli larvae. In addition, the results suggest that biochemical biomarkers can be used for studies involving environmental disturbances.

A New Strategy for the Software-Assisted LC Separations of Ketoconazole and Its Impurities

Analytical quality by design and the use of dissimilar chromatographic systems can be employed to accelerate chromatographic separations. Herein, a software (S-Matrix)-assisted platform was used to proficiently screen, optimize and select the optimal parameters for the chromatographic separation of ketoconazole and its related impurities. This approach evaluated the various chromatographic parameters in a stepwise manner based on the statistical tools and provided an in-depth understanding of the critical parameters influencing the peak selectivities and separations. It was demonstrated that dissimilar conditions, such as different stationary phases, mobile phase pH and organic modifiers (i.e., critical method variables), can improve the peak resolution, while the critical quality attributes can provide conditions appropriate for quantification purposes via a quality target analytical method. Furthermore, an orthogonal method was established to support the primary method. The orthogonality between the two methods was defined by the correlation matrix between the two systems using the Pearson correlation coefficient and was found to be 0.12. Using the optimized method, the primary method was validated as per International Council for Harmonization in the range of 0.05-1.0% for impurities and 80.0-120.0% for ketoconazole, thereby indicating the suitability of the method for use in quality control laboratories.

Ecotoxicological effect of ketoconazole on the antioxidant system of Daphnia similis

The occurrence of emerging pharmaceutical pollutants (i.e. small drugs, antibiotics) present in aquatic environments shown to be a current environmental problem still without apparent solution. In this regard, the use of ecotoxicological techniques has been shown fundamental for the appraisal of damage to affected living organisms. Herein, ecotoxicological tests were conducted, focusing on the evaluation of the effects of ketoconazole (KTZ) on the antioxidant system of the model body Daphnia similis. In order to study the biochemical changes caused by KTZ in the antioxidant system, the enzymatic biomarkers glutathione S-transferase (GST), catalase (CAT), and ascorbate peroxidase (APX) were monitored. Toxicological tests were conducted using KTZ concentrations (0-10 μg·L^-1). Prolonged exposure to KTZ (336 h) caused changes upon the expression of antioxidant enzymes and simultaneously affected the reproductive system in those organisms. Moreover, a decrease in GST and APX activity was observed caused by KTZ exposure, respectively 79.2% (3.53 μmol min^-1 mg^-1 protein) and 24.4% (0.88 μmol min^-1 mg^-1 protein). On the other hand, it was observed an increase of 27% (0.17 μmol min^-1 mg^-1 protein) in CAT activity. Through this study, it was possible to observe the toxicological effects of KTZ, which proves its action as an oxidative stress-inducing agent and endocrine modifier in daphnids organisms.

Qualitative and quantitative assessment of related substances in the Compound Ketoconazole and Clobetasol Propionate Cream by HPLC-TOF-MS and HPLC

Related substances in pharmaceutical formulations are associated with their safety, efficacy and stability. However, there is no overall study already published on the assessment of related substances in the Compound Ketoconazole and Clobetasol Propionate Cream. In this work, a reliable HPLC-TOF-MS qualitative method was developed for the analysis of related substances in this preparation with a quick and easy extraction procedure. Besides the active pharmaceutical ingredients, two compounds named ketoconazole impurity B′ optical isomer and ketoconazole impurity E were identified. Furthermore, a new HPLC method for qualitative and quantitative assessment on related substances and degradation products, which were found in the stability test, was established and validated. The single standard to determine multi-components method was applied in the quantitative analysis, which was an effective way for reducing cost and improving accuracy. This study can provide a creative idea for routine analysis of quality control of the Compound Ketoconazole and Clobetasol Propionate Cream.

Itraconazole cis-diastereoisomers activate aryl hydrocarbon receptor AhR and pregnane X receptor PXR and induce CYP1A1 in human cell lines and human hepatocytes

Triazole antimycotic itraconazole contains in its structure three chiral centres; therefore, it forms eight stereoisomers. Commercial preparations of itraconazole are a mixture of four cis-diastereoisomers. There is much evidence that efficacy, adverse effects, and toxicity of chiral drugs may be stereospecific. Therefore, we have prepared 4 pure cis-diastereoisomers of itraconazole and investigated their effects on transcriptional activities of xenoreceptors aryl hydrocarbon receptor AhR and pregnane X receptor PXR. Gene reporter assays showed that itraconazole dose-dependently activated both AhR and PXR, and the activation of AhR but not of PXR was enantiospecific. Itraconazole diastereoisomers transformed AhR and PXR into their DNA-binding forms, as demonstrated by electromobility shift assays. Cytochrome P450 CYP1A1 mRNA and protein were induced by itraconazole diastereoisomers in human hepatoma cells HepG2, human skin cells HaCaT, and in primary human hepatocytes. The expression of CYP3A4 in human intestinal LS180 cells was not influenced by itraconazole, but we observed downregulation of CYP3A4 in human hepatocytes. Collectively, we show that itraconazole is a dual activator of AhR and PXR, with differential effects on the target genes for xenoreceptors. The enantiospecific pattern was observed only in gene reporter assays for AhR. The data presented here might be of toxicological and clinical importance.

Hydroxystilbenes and methoxystilbenes activate human aryl hydrocarbon receptor and induce CYP1A genes in human hepatoma cells and human hepatocytes

Natural polyphenol resveratrol (trihydroxystilbene) is a partial agonist of human aryl hydrocarbon receptor AhR, thereby, displaying a plethora of biological effects. Biological activities of metoxylated and hydroxylated stilbenes were studied in the past. The aim of the current study was to describe the effects of 13 different hydroxy- and methoxystilbenes, including their cis/trans isomers on the transcriptional activity of AhR and the expression of CYP1A genes in hepatic cancer cells HepG2 and in primary human hepatocytes. Techniques of gene reporter assays, qRT-PCR, Simple Western blotting by Sally Sue™ and electrophoretic mobility shift assay EMSA were employed. All compounds activated AhR, but their efficacies, potencies and dose-response profiles differed substantially. The strongest activators of AhR and inducers of CYP1A1 in HepG2 cells were DMU-212 ((E)-3,4,5,4´-tetramethoxystilbene), trans-piceatannol, cis-piceatannol, trans-trismethoxyresveratrol and trans-pinostilbene. While DMU-212 and trans-trismethoxyresveratrol also induced CYP1A1 and CYP1A2 in primary human hepatocytes, the effects of trans-piceatannol, cis-piceatannol and trans-pinostilbene weaned off. On the other hand, trans-4-methoxystilbene was strong CYP1A inducer in hepatocytes but not in HepG2 cells. Differences between effects of stilbenes in HepG2 cells and human hepatocytes are probably due to the extensive phase I and phase II xenobiotic metabolism in human hepatocytes. The data obtained may be of toxicological relevance.