A preliminary assessment of oral monepantel's tolerability and pharmacokinetics in individuals with treatment-refractory solid tumors.

PURPOSE: Monepantel is an approved veterinary anthelmintic with a strong safety profile. Preclinical evidence suggests novel mTOR pathway-associated anticancer activity. An open-label Phase I trial assessed tolerability, pharmacokinetics, pharmacodynamics and PET-CT imaging following oral Zolvix® monepantel administration to adults with treatment refractory, progressing and unresectable solid tumors. METHODS: Subjects were scheduled to daily home-based monepantel administration for 28 days in a 3 + 3 dose escalation study (5.0, 25.0 and 62.5 mg/kg bw). RESULTS: Of 41 reported drug-related AEs, 68% were Grade 1 and 24% were Grade 2; 35 AEs related to gastrointestinal effects including very poor palatability. DLT and MTD could not be determined due to early termination. Myelosuppression was not observed at the lowest level tested. Three of four Cohort 1 subjects had reduced mTOR pathway marker p-RPS6KB1 levels in PBMCs and achieved RECISTv1.1 SD by CT; one had progressive bony metastases by FDG-PET. One subject recorded PD on day 28, correlating with no detectable plasma monepantel from day 7. Monepantel sulfone dominated monepantel in pharmacokinetics. Both Cohort 2 subjects withdrew early due to AEs and the trial was terminated. CONCLUSIONS: Short-term 5 mg/kg bw monepantel administration provides a combined steady-state trough plasma monepantel and monepantel sulfone concentration of 0.5 µM. Gastrointestinal AEs including very poor palatability are concerning and suggested to be resolved by future drug product reformulation. RECISTv1.1, p-RPS6KB1 and plasma tumor marker outcomes provide preliminary evidence of anticancer activity.

Metabolic pathways of anthelmintic drug monepantel in sheep and in its parasite (Haemonchus contortus).

Monepantel (MOP) is a new anthelmintic drug intended for the treatment and control of gastrointestinal roundworms (nematodes) infection and associated disease in sheep. The aim of our study was to find out metabolic pathways of MOP in sheep in vivo and in its parasite Haemonchus contortus ex vivo. MOP biotransformation in two H. contortus strains with different sensitivity to anthelmintics was also compared. Ultra high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) technique is used for the identification of MOP metabolites in ovine urine, faeces, and nematodes. MOP biotransformation study in sheep in vivo led to the identification of 13 MOP metabolites; 7 of them have not been described previously in in vitro study. The study of MOP biotransformation in H. contorus ex vivo reveals four MOP metabolites. The nitrile hydrolysis as a new biotransformation pathway in helminths ex vivo is reported here for the first time. Unlike sheep, H. contorus nematodes are not able to metabolize MOP via phase II biotransformation. Nematodes of resistant White river (WR) strain form more types of MOP metabolites than nematodes of sensitive inbred susceptible Edinburgh (ISE) strain. Based on obtained results, schemes of metabolic pathways of MOP in sheep and nematodes are proposed.

Investigation of the metabolism of monepantel in ovine hepatocytes by UHPLC/MS/MS.

Monepantel (MOP) belongs to a new class of anthelmintic drugs known as aminoacetonitrile derivatives. It was approved for use in veterinary practice in Czech Republic in 2011. So far, biotransformation and transport of MOP in target animals have been studied insufficiently, although the study of metabolic pathways of anthelmintics is very important for the efficacy of safety of therapy and evaluation of the risk of drug-drug interactions. The aim of this study was to identify MOP metabolites and to suggest the metabolic pathways of MOP in sheep. For this purpose, primary culture of ovine hepatocytes was used as a model in vitro system. After incubation, medium samples and homogenates of hepatocytes were extracted separately using solid-phase extraction. Analysis was performed using a hybrid quadrupole-time-of-flight analyzer with respect to high mass accuracy measurements in full scan and tandem mass spectra for the confirmation of an elemental composition. The obtained results revealed S-oxidation to sulfoxide and sulfone and arene hydroxylation as MOP phase I biotransformations. From phase II metabolites, MOP glucuronides, sulfates, and acetylcysteine conjugates were found. Based on the obtained results, a scheme of the metabolic pathway of MOP in sheep has been proposed.

Isolation, identification, and culture optimization of a novel glycinonitrile-hydrolyzing fungus-Fusarium oxysporum H3.

Microbial transformation of glycinonitrile into glycine by nitrile hydrolase is of considerable interest to green chemistry. A novel fungus with high nitrile hydrolase was newly isolated from soil samples and identified as Fusarium oxysporum H3 through 18S ribosomal DNA, 28S ribosomal DNA, and the internal transcribed spacer sequence analysis, together with morphology characteristics. After primary optimization of culture conditions including pH, temperature, carbon/nitrogen sources, inducers, and metal ions, the enzyme activity was greatly increased from 326 to 4,313 U/L. The preferred carbon/nitrogen sources, inducer, and metal ions were glucose and yeast extract, caprolactam, and Cu(2+), Mn(2+), and Fe(2+), respectively. The maximum enzyme formation was obtained when F. oxysporum H3 was cultivated at 30 °C for 54 h with the initial pH of 7.2. There is scanty report about the optimization of nitrile hydrolase production from nitrile-converting fungus.

Changes in apical dendritic structure correlate with sustained ERK1/2 phosphorylation in medial prefrontal cortex of a rat model of dopamine D1 receptor agonist sensitization.

Rats lesioned with 6-hydroxydopamine (6-OHDA) as neonates exhibit behavioral and neurochemical abnormalities in adulthood that mimic Lesch-Nyhan disease, schizophrenia, and other developmental disorders of frontostriatal circuit dysfunction. In these animals a latent sensitivity to D1 agonists is maximally exposed by repeated administration of dopamine agonists in the postpubertal period (D1 priming). In neonate-lesioned, adult rats primed with SKF-38393, we found selective, persistent alterations in the morphology of pyramidal neuron apical dendrites in the prelimbic area of the medial prefrontal cortex (mPFC). In these animals, dendrite bundling patterns and the typically straight trajectories of primary dendritic shafts were disrupted, whereas the diameter of higher-order oblique branches was increased. Although not present in neonate-lesioned rats treated with saline, these morphological changes persisted at least 21 days after repeated dosing with SKF-38393, and were not accompanied by markers of neurodegenerative change. A sustained increase in phospho-ERK immunoreactivity in wavy dendritic shafts over the same period suggested a relationship between prolonged ERK phosphorylation and dendritic remodeling in D1-primed rats. In support of this hypothesis, pretreatment with the MEK1/2-ERK1/2 pathway inhibitors PD98059 or SL327, prior to each priming dose of SKF-38393, prevented the morphological changes associated with D1 priming. Together, these findings demonstrate that repeated stimulation of D1 receptors in adulthood interacts with the developmental loss of dopamine to profoundly and persistently modify neuronal signaling and dendrite morphology in the mature prefrontal cortex. Furthermore, sustained elevation of ERK activity in mPFC pyramidal neurons may play a role in guiding these morphological changes in vivo.

Interaction of biogenic amines with components of cigarette smoke. Formation of cyanomethylamine derivatives.

A reaction of the biogenic amines 5-hydroxytryptamine, dopamine, histamine, p-tyramine, beta-phenylethylamine and tryptamine with components of cigarette smoke was observed. The adducts formed from 5-hydroxytryptamine and beta-phenylethylamine were purified by chromatographic procedures and identified by high resolution mass spectrometry. The structures of some of these compounds were established as cyanomethylamine derivatives, i.e. RCH2CH2NHCH2CN. In the case of 5-hydroxytryptamine, a cyanomethyl-beta-1,2,3,4-tetrahydrocarboline product formed via a Pictet-Spengler condensation reaction was isolated. The mass spectra of such adducts and their fragment ions were observed to be identical to those of chemically synthesized cyanomethylamines. Both formaldehyde and cyanide, which are known to be present in cigarette smoke, were involved in the reaction with the primary amines. The reaction was time dependent and was enhanced by an increase in temperature or by incubation under alkaline conditions. Cyanomethyl adduct formation was increased when smoke from cigarettes with higher tar and nicotine content was used. When the amines were incubated with human saliva obtained after cigarette smoking, cyanomethylamine products were readily detected.

Comparative effects of indole and aminoacetonitrile derivatives on dimethylnitrosamine-demethylase and aryl hydrocarbon hydroxylase activities.

The effect of in vivo administration of indole and five 3-indolyl derivatives including L-tryptophan, as well as of aminoacetonitrile and 3 of its derivatives, were studied on the carcinogen-metabolizing hepatic mixed-function oxidases dimethylnitrosamine (DMN)-demethylase I and II and aryl hydrocarbon hydroxylase (AHH). Indole, 3-indolylmethanol, 3-indolyl-acetonitrile, 3-indolylacetone and L-tryptophan induce AHH activity from 3- to 6-fold of the control level, whereas beta-3-indolylethanol has no effect; the latter compound produces a 21% decrease of the endoplasmic reticulum content in the tissue. Only L-tryptophan induces DMN-demethylase I and only L-tryptophan and 3-indolylmethanol induce DMN-demethylase II, representing a doubling of enzyme activity in all 3 instances. Aminoacetonitrile is a potent repressor of DMN-demethylase I. Substitutions on the amino group bring about strong decrease or abolishment of mixed-function oxidase repressor activity; thus, iminodiacetonitrile has only about 1/5th the repressor activity of the parent compound, whereas nitrilotriacetonitrile and dimethylaminoacetonitrile appear to be inactive. Aminoacetonitrile and its derivatives studied have no effect on DMN-demethylase II and AHH activities. The mixed-function oxidase-modifying effects of the indole compounds and of aminoacetonitrile and its derivatives illustrate the potential complexity of effects of dietary constituents on the carcinogenic responses.

[Comparative pharmacological effects of dl-amphetaminil and dl-amphetamine in the rat]. / Vergleich pharmakologischer Effekte von dl-Amphetaminil und dl-Amphetamin bei der Ratte

The present investigation shows that amphetamine and amphetaminil produce identical pharmacological effects (increase in motility and body temperature, anorexia, stereotypic behaviour). There was neither a qualitative difference under "open field" conditions nor a difference in the capacity of modifying the reserpine induced syndrome. In isomolar doses amphetamine was somewhat more effective. Almost the same amounts of amphetamine were found in blood and brain following amphetamine or amphetaminil administration, with exception of somewhat higher peak levels after amphetamine. These results favor the hypothesis that amphetaminil effects are produced by the amphetamine molecule.

Studies on the CNS-availability of amphetamine from amphetaminil.

The biotransformation of amphetaminil to amphetamine was confirmed using 3H- and 14C-labelled ampehtaminil. The metabolites were isolated, identified and quantified from blood, brain, adipose tissue and urine. These studies showed that the intact molecule of amphetaminil passes into the circulation only to a very small extent. The time spent by the amphetaminil in the alimentary canal does not appear to be a critical factor in the stability and degradation of this substance. The proportion of unchanged amphetaminil represents no more than 2% of the total radioactivity in the blood. The amphetamine, which results from the cleavage of amphetaminil, enters the CNS and is excreted in the urine after hydroxylation and glucuronidation. The other cleavage product, benzaldehyde, seems to be rapidly converted into hippuric acid, which is excreted. Amphetaminil is enriched in adipose tissue, especially after i.p. injection; but this fraction will be cleaved upon re-entering the blood, and it can only enter the brain as amphetamine.

[Stability of amphetaminil. 2. In vivo studies]. / Untersuchungen zur Stabilität von Amphetaminil

The metabolism of radioactively labelled alpha-phenyl-alpha-N-(beta-phenyl-isopropyl)-aminoacetonitrile (amphetaminil, AN 1-R) (tritium-labelled in the amphetamine-part, 14C-labelled in the benzaldehyde-part of the molecule) in the rat was examined. In the body amphetaminil is cleft very quickly into the original compounds of its chemical synthesis (amphetamine, benzaldehyde and hydrocyanic acid) independent of the mode of application (i.p. or oral). Blood: In the interval from 5-90 min after application of amphetaminil only 1-2 percent of the total radioactivity are received from amphetaminil. The main part of the tritium- and 14C-radioactivity is distributed among amphetamine, p-OH-amphetamineglucuronide and hippuric acid. Brain: In the brain only a minimum amount of amphetaminil can be present, if any. The share of amphetamine of the total activity amounts to more than 90 percent. Adipose tissue: In the adipose tissue the ratio of the two isotopes of the substances extracted at pH 5 is almost equal to that of the administered amphetaminil. It seems that the substance is enriched there because of its pronounced lipophilia. After i.p. application the concentration is about 12 times higher than after oral application. Urine: In the urine there could be detected amphetamine, p-OH-amphetamineglucuronide and hippuric acid but no amphetaminil.