Synthesis and Evaluation of Structurally Diverse C-2-Substituted Thienopyrimidine-Based Inhibitors of the Human Geranylgeranyl Pyrophosphate Synthase.

Novel analogues of C-2-substituted thienopyrimidine-based bisphosphonates (C2-ThP-BPs) are described that are potent inhibitors of the human geranylgeranyl pyrophosphate synthase (hGGPPS). Members of this class of compounds induce target-selective apoptosis of multiple myeloma (MM) cells and exhibit antimyeloma activity in vivo. A key structural element of these inhibitors is a linker moiety that connects their (((2-phenylthieno[2,3-d]pyrimidin-4-yl)amino)methylene)bisphosphonic acid core to various side chains. The structural diversity of this linker moiety, as well as the side chains attached to it, was investigated and found to significantly impact the toxicity of these compounds in MM cells. The most potent inhibitor identified was evaluated in mouse and rat for liver toxicity and systemic exposure, respectively, providing further optimism for the potential value of such compounds as human therapeutics.

Identification of 3,4-Dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine Derivatives as Novel Selective Inhibitors of Plasmodium falciparum Dihydroorotate Dehydrogenase.

Plasmodium falciparum's resistance to available antimalarial drugs highlights the need for the development of novel drugs. Pyrimidine de novo biosynthesis is a validated drug target for the prevention and treatment of malaria infection. P. falciparum dihydroorotate dehydrogenase (PfDHODH) catalyzes the oxidation of dihydroorotate to orotate and utilize ubiquinone as an electron acceptor in the fourth step of pyrimidine de novo biosynthesis. PfDHODH is targeted by the inhibitor DSM265, which binds to a hydrophobic pocket located at the N-terminus where ubiquinone binds, which is known to be structurally divergent from the mammalian orthologue. In this study, we screened 40,400 compounds from the Kyoto University chemical library against recombinant PfDHODH. These studies led to the identification of 3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine and its derivatives as a new class of PfDHODH inhibitor. Moreover, the hit compounds identified in this study are selective for PfDHODH without inhibition of the human enzymes. Finally, this new scaffold of PfDHODH inhibitors showed growth inhibition activity against P. falciparum 3D7 with low toxicity to three human cell lines, providing a new starting point for antimalarial drug development.

Nonclinical Safety Profile of Sotorasib, a KRASG12C-Specific Covalent Inhibitor for the Treatment of KRAS p.G12C-Mutated Cancer.

Sotorasib is a first-in-class KRASG12C covalent inhibitor in clinical development for the treatment of tumors with the KRAS p.G12C mutation. A comprehensive nonclinical safety assessment package, including secondary/safety pharmacology and toxicology studies, was conducted to support the marketing application for sotorasib. Sotorasib was negative in a battery of genotoxicity assays and negative in an in vitro phototoxicity assay. Based on in vitro assays, sotorasib had no off-target effects against various receptors, enzymes (including numerous kinases), ion channels, or transporters. Consistent with the tumor-specific target distribution (ie, KRASG12C), there were no primary pharmacology-related on-target effects identified. The kidney was identified as a target organ in the rat but not the dog. Renal toxicity in the rat was characterized by tubular degeneration and necrosis restricted to a specific region suggesting that the toxicity was attributed to the local formation of a putative toxic reactive metabolite. In the 3-month dog study, adaptive changes of hepatocellular hypertrophy due to drug metabolizing enzyme induction were observed in the liver that was associated with secondary effects in the pituitary and thyroid gland. Sotorasib was not teratogenic and had no direct effect on embryo-fetal development in the rat or rabbit. Human, dog, and rat circulating metabolites, M24, M10, and M18, raised no clinically relevant safety concerns based on the general toxicology studies, primary/secondary pharmacology screening, an in vitro human ether-à-go-go-related gene assay, or mutagenicity assessment. Overall, the results of the nonclinical safety program support a high benefit/risk ratio of sotorasib for the treatment of patients with KRAS p.G12C-mutated tumors.

Structure-Based Virtual Screening Identifies Multiple Stable Binding Sites at the RecA Domains of SARS-CoV-2 Helicase Enzyme.

With the emergence and global spread of the COVID-19 pandemic, the scientific community worldwide has focused on search for new therapeutic strategies against this disease. One such critical approach is targeting proteins such as helicases that regulate most of the SARS-CoV-2 RNA metabolism. The purpose of the current study was to predict a library of phytochemicals derived from diverse plant families with high binding affinity to SARS-CoV-2 helicase (Nsp13) enzyme. High throughput virtual screening of the Medicinal Plant Database for Drug Design (MPD3) database was performed on SARS-CoV-2 helicase using AutoDock Vina. Nilotinib, with a docking value of -9.6 kcal/mol, was chosen as a reference molecule. A compound (PubChem CID: 110143421, ZINC database ID: ZINC257223845, eMolecules: 43290531) was screened as the best binder (binding energy of -10.2 kcal/mol on average) to the enzyme by using repeated docking runs in the screening process. On inspection, the compound was disclosed to show different binding sites of the triangular pockets collectively formed by Rec1A, Rec2A, and 1B domains and a stalk domain at the base. The molecule is often bound to the ATP binding site (referred to as binding site 2) of the helicase enzyme. The compound was further discovered to fulfill drug-likeness and lead-likeness criteria, have good physicochemical and pharmacokinetics properties, and to be non-toxic. Molecular dynamic simulation analysis of the control/lead compound complexes demonstrated the formation of stable complexes with good intermolecular binding affinity. Lastly, affirmation of the docking simulation studies was accomplished by estimating the binding free energy by MMPB/GBSA technique. Taken together, these findings present further in silco investigation of plant-derived lead compounds to effectively address COVID-19.

Safety assessment of metarrestin in dogs: A clinical candidate targeting a subnuclear structure unique to metastatic cancer cells.

Pancreatic cancer is a leading cause of cancer-related deaths in the U.S. Ninety percent of patients with stage IV pancreatic cancer die within one year of diagnosis due to complications of metastasis. A metastatic potential of cancer cells has been shown to be closely associated with formation of perinucleolar compartment (PNC). Metarrestin, a first-in-class PNC inhibitor, was evaluated for its toxicity, toxicokinetics, and safety pharmacology in beagle dogs following every other day oral (capsule) administration for 28 days to support its introduction into clinical trials. The study consisted of four dose groups: vehicle; 0.25, 0.75 and 1.50 mg/kg/dose. Metarrestin reached its maximum concentration in blood at 3 h (overall median Tmax) across all doses with a mean t1/2 over 168 h of 55.5 h. Dose dependent increase in systemic exposure (Cmax and AUClast) with no sex difference was observed on days 1 and 27. Metarrestin accumulated from Day 1 to Day 27 at all dose levels and in both sexes by an overall factor of about 2.34. No mortality occurred during the dosing period; however, treatment-related clinical signs of toxicity consisting of hypoactivity, shaking/shivering, thinness, irritability, salivation, abnormal gait, tremors, ataxia and intermittent seizure-like activity were seen in both sexes at mid and high dose groups. Treatment-related effects on body weight and food consumption were seen at the mid and high dose levels. Safety pharmacology study showed no treatment-related effects on blood pressure, heart rate, corrected QT, PR, RR, or QRS intervals, or respiratory function parameters (respiratory rate, tidal volume, minute volume). There were no histopathological changes observed, with the exception of transient thymic atrophy which was considered to be non-adverse. Based primarily on clinical signs of toxicity, the No Observed Adverse Effect Level (NOAEL) in dogs was considered to be 0.25 mg/kg metarrestin after every other day dosing for 28 days with a mean of male and female Cmax = 82.5 ng/mL and AUClast = 2521 h*ng/mL, on Day 27.

Simultaneous determination and risk assessment of metalaxyl and azoxystrobin in potato by liquid chromatography with tandem mass spectrometry.

A liquid chromatography with tandem mass spectrometry method was developed and validated to simultaneously determine metalaxyl and azoxystrobin in soil, potato, and potato foliage samples. The samples were extracted by 20 mL of acetonitrile and purified with dispersive solid-phase extraction using octadecyl silane as sorbent. The method showed good linearity (determination coefficients ≥ 0.9926) for metalaxyl (2.5-500 ng/mL) and azoxystrobin (5-1000 ng/mL). The limits of detection and quantification for both fungicides were 1.5-20 µg/kg. The average recoveries in soil, potato, and potato foliage were 83.07-92.87% for metalaxyl and 82.71-98.53% for azoxystrobin. The intra- and inter-day relative standard deviations were all less than 9%. The method was successfully applied on the residual analysis of metalaxyl and azoxystrobin in field trial samples. The results showed that the concentrations of metalaxyl and azoxystrobin in potato samples collected from Guizhou and Hunan were below 50 and 100 µg/kg (maximum residue limit set by China), respectively, at 5 days after the last application. When following the recommended application manual, metalaxyl and azoxystrobin do not present health concerns to the population because the risk quotients are far below 100%. All the above data could help and promote the safe and proper use of metalaxyl and azoxystrobin in potato.

Pharmacodynamics of the Orotomides against Aspergillus fumigatus: New Opportunities for Treatment of Multidrug-Resistant Fungal Disease.

F901318 is an antifungal agent with a novel mechanism of action and potent activity against Aspergillus spp. An understanding of the pharmacodynamics (PD) of F901318 is required for selection of effective regimens for study in phase II and III clinical trials. Neutropenic murine and rabbit models of invasive pulmonary aspergillosis were used. The primary PD endpoint was serum galactomannan. The relationships between drug exposure and the impacts of dose fractionation on galactomannan, survival, and histopathology were determined. The results were benchmarked against a clinically relevant exposure of posaconazole. In the murine model, administration of a total daily dose of 24 mg/kg of body weight produced consistently better responses with increasingly fractionated regimens. The ratio of the minimum total plasma concentration/MIC (Cmin/MIC) was the PD index that best linked drug exposure with observed effect. An average Cmin (mg/liter) and Cmin/MIC of 0.3 and 9.1, respectively, resulted in antifungal effects equivalent to the effect of posaconazole at the upper boundary of its expected human exposures. This pattern was confirmed in a rabbit model, where Cmin and Cmin/MIC targets of 0.1 and 3.3, respectively, produced effects previously reported for expected human exposures of isavuconazole. These targets were independent of triazole susceptibility. The pattern of maximal effect evident with these drug exposure targets was also apparent when survival and histopathological clearance were used as study endpoints. F901318 exhibits time-dependent antifungal activity. The PD targets can now be used to select regimens for phase II and III clinical trials.IMPORTANCE Invasive fungal infections are common and often lethal. There are relatively few antifungal agents licensed for clinical use. Antifungal drug toxicity and the emergence of drug resistance make the treatment of these infections very challenging. F901318 is the first in a new class of antifungal agents called the orotomides. This class has a novel mechanism of action that involves the inhibition of the fungal enzyme dihydroorotate dehydrogenase. F901318 is being developed for clinical use. A deep understanding of the relationship between dosages, drug concentrations in the body, and the antifungal effect is fundamental to the identification of the regimens to administer to patients with invasive fungal infections. This study provides the necessary information to ensure that the right dose of F901318 is used the first time. Such an approach considerably reduces the risks in drug development programs and ensures that patients with few therapeutic options can receive potentially life-saving antifungal therapy at the earliest opportunity.

Evaluation of 7-arylaminopyrazolo[1,5-a]pyrimidines as anti-Plasmodium falciparum, antimalarial, and Pf-dihydroorotate dehydrogenase inhibitors.

Malaria remains one of the most serious global infectious diseases. An important target for antimalarial chemotherapy is the enzyme dihydroorotate dehydrogenase from Plasmodium falciparum (PfDHODH), which is responsible for the conversion of dihydroorotate to orotate in the de novo pyrimidine biosynthetic pathway. In this study, we have designed and synthesized fifteen 7-arylpyrazolo[1,5-a]pyrimidine derivatives using ring bioisosteric replacement and molecular hybridization of functional groups based on the highly active 5-methyl-N-(naphthalen-2-yl)-2-(trifluoromethyl)- [1,2,4]triazolo[1,5-a]pyrimidin-7-amine. The compounds were tested against Plasmodium falciparum, as antimalarials in mice with P. berghei, and as inhibitors of PfDHODH. Thirteen compounds were found to be active against P. falciparum, with IC50 values ranging from 1.2 ± 0.3 to 92 ± 26 µM in the anti-HRP2 and hypoxanthine assays. Four compounds showed the highest selective index (SI), which is a ratio between cytotoxicity and activity in vitro. The inhibition of PfDHODH showed that compound 30 (R2 = CH3; R5 = CF3; Ar = 7-ß-naphthyl) displayed higher and selective inhibitory activity, with IC50 = 0.16 ± 0.01 µM, followed by 25 (R2 = CH3; R5 = CH3; Ar = 7-ß-Naphthyl) and 19 (R2 = CF3; R5 = CF3; Ar = 7-ß-naphthyl), with IC50 = 4 ± 1 µM and 6 ± 1 µM, respectively. The trifluoromethyl group at the 2- or 5-positions of the pyrazolo[1,5-a]pyrimidine ring led to increased drug activity. The docking results agreed with the values obtained from enzymatic assays.

Ranking the Binding Energies of p53 Mutant Activators and Their ADMET Properties.

The guardian of the genome, p53, is the most mutated protein found in all cancer cells. Restoration of wild-type activity to mutant p53 offers promise to eradicate cancer cells using novel pharmacological agents. Several molecules have already been found to activate mutant p53. While the exact mechanism of action of these compounds has not been fully understood, a transiently open pocket has been identified in some mutants. In our study, we docked twelve known activators to p53 into the open pocket to further understand their mechanism of action and rank the best binders. In addition, we predicted the absorption, distribution, metabolism, excretion and toxicity properties of these compounds to assess their pharmaceutical usefulness. Our studies showed that alkylating ligands do not all bind at the same position, probably due to their varying sizes. In addition, we found that non-alkylating ligands are capable of binding at the same pocket and directly interacting with Cys124. The comparison of the different ligands demonstrates that stictic acid has a great potential as a p53 activator in terms of less adverse effects although it has poorer pharmacokinetic properties.

Discovery of novel Bcr-Abl inhibitors targeting myristoyl pocket and ATP site.

Bcr-Abl plays an essential role in the pathogenesis and development of chronic myeloid leukaemia (CML). Inhibition of Bcr-Abl has great potential for therapeutic intervention in CML. In order to obtain novel and potent Bcr-Abl inhibitors, twenty seven 4,6-disubstituted pyrimidines were synthesized and evaluated herein. The biological results indicated that four compounds of them (C4, C5, C16, and C23) were potent Bcr-Abl inhibitors which were comparable to positive control. Moreover, C4 and C5 displayed promising antiproliferative activity against K562 cells. The results suggested that these 4,6-disubstituted pyrimidines could serve as promising leads for further optimization of Bcr-Abl inhibitors.

Assessment of genotoxicity and acute toxic effect of the imatinib mesylate in plant bioassays.

Imatinib mesylate (IM) is at present one of the most widely used cytostatic drugs in developed countries but information on its ecotoxicological activities is scarce. This article describes the results of the first investigation in which genotoxic and acute toxic properties of the drug were studied in higher plants. IM was tested in two widely used plant bioassays namely in micronucleus (MN) assays with meiotic tetrad cells of Tradescantia (clone #4430) and in mitotic root tip cells of Allium cepa. Additionally, acute toxic effects (inhibition of cell division and growth of roots) were monitored in the onions. Furthermore, we studied the impact of the drug on the fertility of higher plants in pollen abortion experiments with three wildlife species (Chelidonium majus, Tradescantia palludosa and Arabidopsis thaliana). In MN assays with Tradesacantia a significant effect was seen with doses ⩾10µM; the Allium MN assay was even more sensitive (LOEL⩾1.0µM). A significant decrease of the mitotic indices was detected at levels ⩾10µM in the onions and reduction of root growth with ⩾100µM. In the pollen fertility assays clear effects were observed at doses ⩾147.3mgkg(-1). Data concerning the annual use of the drug in European countries (France, Germany, Slovenia) enable the calculation of the predicted environmental concentration (PEC) values which are in the range between 3.3 and 5.0ngL(-1). Although comparisons with the genotoxic potencies of other commonly used cytostatic drugs and with highly active heavy metal compounds show that IM is an extremely potent genotoxin in higher plants, it is evident that the environmental concentrations are ⩾5 orders of magnitude lower as the levels which are required to cause adverse effects.

Pre-clinical pharmacokinetics and acute toxicological evaluation of a monastrol derivative anticancer candidate LaSOM 65 in rats.

1. The present work investigated the pharmacokinetic and tissue distribution as well as acute toxicity of a new chemical entity (NCE), the anticancer candidate LaSOM 65 in Wistar rats. 2. LaSOM 65 pharmacokinetics was investigated after intravenous (i.v., 1 mg/kg) and oral (p.o., 10 and 30 mg/kg) dosing. Tissue distribution was assessed after i.v. bolus dose. Acute toxicity was evaluated after i.v. (1, 2.5 and 5 mg/kg) and p.o. (50, 100 and 150 mg/kg) administration. 3. Short half-life (1.75 ± 0.71 h), a clearance of 0.85 ± 0.18 L/h/kg and a volume of distribution of 1.76 ± 0.24 L/kg were observed after i.v. dosing. The compound showed good bioavailability and linear pharmacokinetics after oral doses. The NCE distributes consistently in lung and fatty tissues, with penetration ratios of 2.7 and 1.4, respectively. The other tissues investigated presented smaller penetration ratios. Adverse clinical symptoms were observed only after i.v. administration, and regressed 3 h after dosing. Compared with controls, no statistical differences were found for serum analysis, body weight and relative organ weight, indicating no acute toxicological effects. 4. Overall, LaSOM 65 showed good pharmacokinetic characteristics and no signs of acute toxicity, indicating that it is a promising anticancer candidate.

Design, synthesis and bioevalution of novel benzamides derivatives as HDAC inhibitors.

A series of novel benzamides derivatives was designed and synthesized as HDAC inhibitors. Exploration of the structure-activity relationships resulted in compounds that are potent in vitro. In addition, the best compound 1a exhibited an acceptable pharmacokinetic profile with bioavailability in rat of 81% and could be considered as a candidate compound for further development.

Toxicity of metalaxyl, azoxystrobin, dimethomorph, cymoxanil, zoxamide and mancozeb to Phytophthora infestans isolates from Serbia.

A study of the in vitro sensitivity of 12 isolates of Phytophthora infestans to metalaxyl, azoxystrobin, dimethomorph, cymoxanil, zoxamide and mancozeb, was conducted. The isolates derived from infected potato leaves collected at eight different localities in Serbia during 2005-2007. The widest range of EC(50) values for mycelial growth of the isolates was recorded for metalaxyl. They varied from 0.3 to 3.9 µg mL(-1) and were higher than those expected in a susceptible population of P. infestans. The EC(50) values of the isolates were 0.16-0.30 µg mL(-1) for dimethomorph, 0.27-0.57 µg mL(-1) for cymoxanil, 0.0026-0.0049 µg mL(-1) for zoxamide and 2.9-5.0 µg mL(-1) for mancozeb. The results indicated that according to effective concentration (EC(50)) the 12 isolates of P. infestans were sensitive to azoxystrobin (0.019-0.074 µg mL(-1)), and intermediate resistant to metalaxyl, dimethomorph and cymoxanil. According to resistance factor, all P. infestans isolates were sensitive to dimethomorph, cymoxanil, mancozeb and zoxamide, 58.3% of isolates were sensitive to azoxystrobin and 50% to metalaxyl. Gout's scale indicated that 41.7% isolates were moderately sensitive to azoxystrobin and 50% to metalaxyl.

Non-clinical safety assessment and toxicokinetics of voriconazole and anidulafungin in the juvenile rat: a combination study design in support of a Paediatric Investigation Plan.

Anidulafungin and voriconazole are potent antifungal agents that may provide a powerful therapeutic option over current therapies when coadministered. A non-clinical combination toxicity study was required as part of the voriconazole Paediatric Investigation Plan. Rats received anidulafungin or voriconazole alone or in combination once daily from postnatal day (PND) 21-56 with a recovery period to PND 84. Doses used were based upon the approximate adult rat no observed adverse-effect level (NOAEL). Transient and reversible reductions in bodyweight, haematology, serum chemistry, liver weight and minimal liver changes were associated with anidulafungin. Voriconazole caused an increase in gamma-glutamyltransferase in female rats only. No increased toxicity was observed with the combination. Toxicokinetics were determined using a validated dual-analyte bioanalytical method. Systemic exposure at juvenile rat NOAELs was comparable to that found with adult rats in previous studies. There were no drug-drug interactions affecting exposure of either drug. Juvenile rats were not more sensitive to each drug dosed alone compared with adult rat data on the single drugs. No novel, additive or synergistic toxicities were noted with the combination in juvenile rats. This study will support future studies of the combination of voriconazole and anidulafungin in children with invasive fungal infection.

Renal toxicity of lisinopril and rosuvastatin, alone and in combination, in Wistar rats.

The aim of study was to evaluate the effect of commonly used lisinopril, rosuvastatin and their combined action on site-specific nephrotoxicity in rats using clusterin and microalbumin nephrotoxic biomarkers and other related parameters using oral gavage. Rosuvastatin at 2 different doses showed increase in urinary microalbumin levels whereas lisinopril and its combination with rosuvastatin at 2 different doses did not show urinary microalbumin excretion indicating beneficial effects of lisinopril in terms of reducing microalbumin. Urinary clusterin levels significantly increased in high-dose treated animals of lisinopril and rosuvastatin. The use of lisinopril plus rosuvastatin at low dose also led to worsened renal function by raising urinary clusterin levels (217 ± 4.6 ng/ml) when compared with the control (143 ± 3.3 ng/ml). Renal histopathology showed multifocal regeneration of tubules indicating proximal tubule damaged. These results indicate that lisinopril (50 mg/kg), rosuvastatin (100 mg/kg), lisinopril+rosuvastatin (20+40 mg/kg) and lisinopril+rosuvastatin (50+100 mg/kg) showed toxicity only on proximal tubules.

Determination and stability of CP-31398 in plasma from experimental animals by LC-MS/MS.

A sensitive and accurate approach for the determination of CP-31398 (N-{2-[(E)-2-(4-methoxy-phenyl)-vinyl]-quinazolin-4-yl}-N',N'-dimethyl-propane-1,3-diamine hydrochloride) in rat and dog plasma by LC-MS/MS was validated to support preclinical toxicological and pharmacological studies. Based on the results of stability experiments with diluted CP-31398 solutions using NMR, LC-MS/MS and LC-Q-TOF, all sample preparation and handling steps were performed under yellow light to avoid CP-31398 decomposition. CP-31398 was extracted by protein precipitation with acetonitrile and separated using a Phenomenex Luna 3µm phenyl-hexyl, 100Å, 30×2.0mm column (rat plasma) or a Phenomenex Synergi 4µ Polar-RP, 80Å, 30×2.0mm column (dog plasma) at a flow rate of 0.30mL/min. The mobile phase consisted of A: 1% formic acid in water and B: 1% formic acid in methanol or acetonitrile. Total run times for rat and dog samples were 7 and 8min, respectively, with accompanying retention times of 1.8 for both columns. A turbo ion spray interface was used as the ion source operating in positive mode. Calibration curves were linear from 5 to 1000ng/mL. Linearity was assessed using the external standard method. Within-run and between-run accuracy was 93-109% of the true value for all analytes with precision (SD) of 8% or less for all experiments. The validated method was applied to preclinical toxicology studies in rats and dogs after oral administration of CP-31398.

Discovery of a novel class of 2-aminopyrimidines as CDK1 and CDK2 inhibitors.

A series of new 2-(2-aminopyrimidin-4-yl)phenol derivatives were synthesized as potential antitumor compounds. Substitution with pyrrolidine-3,4-diol at the 4-position of phenol provided potent inhibitory activity against CDK1 and CDK2. X-ray crystal structural studies were performed to account for the effect of the substituent on both the enzymatic and cell growth inhibitory activities.

Therapeutic and toxicologic studies in a murine model of invasive pulmonary aspergillosis.

Invasive pulmonary aspergillosis remains problematic in immunocompromised patient populations. We studied potential therapeutic options in a murine model of pulmonary aspergillosis in triamcinolone-suppressed DBA/2 mice infected intranasally with conidia from Aspergillus fumigatus. Mice were treated with liposomal-amphotericin B (AmBi; AmBisome), lipid-complexed amphotericin B (ABLC; Abelcet), voriconazole (VCZ), micafungin (MICA), caspofungin (CAS) or deoxycholate amphotericin B (AMBd) given alone or in combination. Monotherapy with AmBi, ABLC, AMBd, CAS or MICA had activity in prolonging survival; however, only AMBd or CAS reduced fungal burden in the lungs and kidneys. Combinations of AmBi plus CAS or MICA prolonged survival, but were not better than monotherapy. VCZ was ineffective and AMBd plus CAS showed a possible antagonism. AmBi or ABLC at higher dosages, or loading-doses of AmBi resulted in reduced survival. Histopathology showed increased incidence of serious renal and mild hepatic toxicity in triamcinolone-treated mice given an amphotericin B regimen compared to no or only triamcinolone (minimal renal changes occurred with CAS or VCZ with or without triamcinolone); suggestive of combined toxicity of triamcinolone and the amphotericin B in AmBi or ABLC. Infected treated mice showed progressive pulmonary disease including abscesses, angioinvasion and abundant intralesional fungi. High loading-doses of AmBi were associated with nephrosis and damage to other tissues. No monotherapy or combination regimen showed superiority for the treatment of pulmonary aspergillosis in corticosteroid suppressed mice and the potential for combined drug toxicity was enhanced in these mice. High dosages of lipid-formulated amphotericin B also proved unsatisfactory. Additional studies are needed to evaluate improved treatment.

Preparation and characterization of novel 4-bromo-3,4-dimethyl-1-phenyl-2-phospholene 1-oxide and the analogous phosphorus heterocycles or phospha sugars.

4-Bromo-3,4-dimethyl-1-phenyl-2-phospholene 1-oxide (3c) was first synthesized from 3,4-dimethyl-1-phenyl-2-phospholene 1-oxide (2c) by a bromo-radical substitution reaction occurred at C-4 position by N-bromosuccinimide and 2,2'-azobisisobutyronitrile. The novel phospha sugar analogue 3c exerted high anti-proliferative effect on U937 cells evaluated by MTT in vitro methods and was much more efficient than that of Gleevec, which is known as a molecule targeting chemotherapeutical agent. The substitution of 2-phospholenes at C-3 and C-4 position with methyl groups as well as 4-bromo substituent suggests a good anti-proliferative effect.