Burkhard Fugmann

First Assessment in Humans of the Safety, Tolerability, Pharmacokinetics, and Ex Vivo Pharmacodynamic Antimalarial Activity of the New Artemisinin Derivative Artemisone

ABSTRACT In preclinical studies, artemisone (BAY 44-9585), a new artemisinin derivative, was shown to possess enhanced efficacy over artesunate, and it does not possess the neurotoxicity characteristic of the current artemisinins. In a phase I program with double-blind, randomized, placebo-controlled, single and multiple ascending oral-dose studies, we evaluated the safety, tolerability, pharmacokinetics, and ex vivo pharmacodynamic antimalarial activity of artemisone. Single doses (10, 20, 30, 40, and 80 mg) and multiple doses (40 and 80 mg daily for 3 days) of artemisone were administered orally to healthy subjects. Plasma concentrations of artemisone and its metabolites were measured by liquid chromatography/tandem mass spectrometry (LC/MS-MS). Artemisone was well tolerated, with no serious adverse events and no clinically relevant changes in laboratory and vital parameters. The pharmacokinetics of artemisone over the 10- to 80-mg range demonstrated dose linearity. After the single 80-mg dose, artemisone had a geometric mean maximum concentration of 140.2 ng/ml (range, 86.6 to 391.0), a short elimination half-life (t1/2) of 2.79 h (range, 1.56 to 4.88), a high oral clearance of 284.1 liters/h (range, 106.7 to 546.7), and a large volume of distribution of 14.50 liters/kg (range, 3.21 to 51.58). Due to artemisones short t1/2, its pharmacokinetics were comparable after single and multiple dosing. Plasma samples taken after multiple dosing showed marked ex vivo pharmacodynamic antimalarial activities against two multidrug-resistant Plasmodium falciparum lines. Artemisone equivalent concentrations measured by bioassay revealed higher activity than artemisone measured by LC/MS-MS, confirming the presence of active metabolites. Comparable to those of other artemisinins, artemisones t1/2 is well suited for artemisinin-based combination therapy for the treatment of P. falciparum malaria.

In vitro pharmacology of BAY X1005, a new inhibitor of leukotriene synthesis

BAY X1005, (R)-2-[4-(quinolin-2-yl-methoxy)phenyl]-2-cyclopentyl acetic acid, is an enantioselective inhibitor of leukotriene biosynthesis. It effectively inhibits the synthesis of LTB4 in A23187-stimulated leukocytes from rats, mice and humans (IC50 0.026, 0.039 and 0.22 μmol/l, respectively) as well as the formation of LTC4 (IC50 0.021 μmol/l) in mouse peritoneal macrophages stimulated with opsonized zymosan. The compound is, however, less active in inhibiting LTB4 synthesis in human whole blood (IC50 17.0 and 11.6 μmol/l, as measured by RIA or HPLC, respectively). BAY X1005 exhibits a high enantioselectivity in human whole blood (31 times over the (S)-enantiomer). BAY X1005 is shown to be a selective inhibitor of the formation of 5-lipoxygenase-derived metabolitesin vitro, without effects on other routes of arachidonic acid metabolism such as 12-lipoxygenase in human whole blood and cyclooxygenase in both mouse macrophages and human whole blood. BAY X1005 is devoid of any antioxidant activity (methemoglobin induction and xanthine-xanthine oxidase assay), without effects on granule release and with only weak effects on reactive oxygen species generation in human PMNL.

Efficacy of Topically Delivered Moxifloxacin against Wound Infection by Pseudomonas aeruginosa and Methicillin-Resistant Staphylococcus aureus

ABSTRACT Wound infection is a common risk for patients with chronic nonhealing wounds, causing high morbidity and mortality. Currently, systemic antibiotic treatment is the therapy of choice, despite often leading to several side effects and the risk of an insufficient tissue penetration due to impaired blood supply. If systemically delivered, moxifloxacin penetrates well into inflammatory blister fluid, muscle, and subcutaneous adipose tissues and might therefore be a possible option for the topical treatment of skin and infected skin wounds. In this study, topical application of moxifloxacin was investigated in comparison to mupirocin, linezolid, and gentamicin using a porcine wound infection and a rat burn infection model. Both animal models were performed either by an inoculation with methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa. Wound fluid, tissue, and blood samples were taken, and bacterial counts as well as the moxifloxacin concentration were determined for a 14-day follow-up. A histological comparison of the rat burn wound tissues was performed. Both strains were susceptible to moxifloxacin and gentamicin, whereas mupirocin and linezolid were effective only against MRSA. All antibiotics showed efficient reduction of bacterial counts, and except with MRSA, infected burn wounds reached bacterial counts below 105 CFU/g tissue. Additionally, moxifloxacin was observed to promote wound healing as determined by histologic analysis, while no induction of bacterial resistance was observed during the treatment period. The use of topical antibiotics for the treatment of infected wounds confers many benefits. Moxifloxacin is therefore an ideal candidate, due to its broad antibacterial spectrum, its high efficiency, and its potential to promote wound healing.

Necatorone, an alkaloidal pigment from the gilled toadstool lactarius necator (agaricales)☆

Abstract Necatorone, an alkaloid possessing an unusual 5,10-dihydroxydibenzo [de,h] [1,6] naphthyridin-6-one structure has been isolated from fruit-bodies of the toadstool Lactarius necator .

Pivotal Role for α1-Antichymotrypsin in Skin Repair

α1-Antichymotrypsin (α1-ACT) is a specific inhibitor of leukocyte-derived chymotrypsin-like proteases with largely unknown functions in tissue repair. By examining human and murine skin wounds, we showed that following mechanical injury the physiological repair response is associated with an acute phase response of α1-ACT and the mouse homologue Spi-2, respectively. In both species, attenuated α1-ACT/Spi-2 activity and gene expression at the local wound site was associated with severe wound healing defects. Topical application of recombinant α1-ACT to wounds of diabetic mice rescued the impaired healing phenotype. LC-MS analysis of α1-ACT cleavage fragments identified a novel cleavage site within the reactive center loop and showed that neutrophil elastase was the predominant protease involved in unusual α1-ACT cleavage and inactivation in nonhealing human wounds. These results reveal critical functions for locally acting α1-ACT in the acute phase response following skin injury, provide mechanistic insight into its function during the repair response, and raise novel perspectives for its potential therapeutic value in inflammation-mediated tissue damage.

Evaluation of artemisone combinations in Aotus monkeys infected with Plasmodium falciparum.

ABSTRACT Artemisone (single oral dose, 10 mg/kg of body weight) cured nonimmune Aotus monkeys of their Plasmodium falciparum infections when combined with mefloquine (single oral dose, 5 and 10 mg/kg but not 2.5 mg/kg). In combination with amodiaquine (20 mg/kg/day), artemisone (10 mg/kg/day) given orally for 3 days cured all infected monkeys. Three days of treatment with artemisone (30 mg/kg/day) and clindamycin (100 mg/kg/day) was also curative.

Alkaloidal pigments from Lactarius necator and L. atroviridis

Abstract Two new alkaloids, 4,4′-binecatorone and 10-deoxy-4,4′-binecatorone, have been isolated from fruiting bodies of Lactarius necator . The American species L. atroviridis contains 10,10′-dideoxy-4,4′-binecatorone as the main alkaloid which is responsible for the green appearance of this toadstool.

Synthesis of necatorone

Abstract The mutagenic fungal alkaloid necatorone has been obtained by a six-step synthesis starting from 2-(3,4-dimethoxyphenyl) ethylamine and 2-nitro-5-methoxybenzoyl chloride.

Pigments from the Puffball Calvatia rubro-flava − Isolation, Structural Elucidation and Synthesis

The orange pigment rubroflavin (1) from the dried fruit bodies of Calvatia rubro-flava (Lycoperdaceae) owes its high optical rotation to a methanesulfinyl group directly attached to a 1,4-benzoquinone semicarbazone chromophore. Rubroflavin is present in fresh fungi in its leuco form 4, which is easily oxidized to 1. Thermal fragmentation of 1 yields (−)-3-methanesulfinyl-5-(methylthio)phenol (6), whose configuration was assigned as (S) by quantum mechanical calculations. This result is supported by CD comparison of 6 with (S)-4-(methanesulfinyl)toluene, and the synthesis of (S)-1 from esters of deoxyrubroflavin (8) by stereoselective sulfoxidation. In the same manner, optically active (S,S)-oxyrubroflavin (2) and (S)-craniformin (3) were obtained. NMR measurements in different solvents indicate that 1 and the related 1,4-benzoquinone semicarbazones are in equilibrium with their azophenol tautomers.

Moxifloxacingel gegen MRSA im infizierten Großtiermodell

Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of infections in wounds and associated with high morbidity [1]. The emergence of bacterial resistance to multiple antibiotics [2] has led to an increased urgency to develop new therapeutic options for wound infections. The aim of this study was to assess the antimicrobial activity of moxifloxacin in a preclinical large animal model of MRSA wound infection. Methods: Six full thickness BO-wound chambers [3] were implanted on each flank of 2 female Goettingen minipigs under general anaesthesia. 7 days after implantation wounds were inoculated with 1 × 108 colony forming units (cfu) of MRSA. After wound infection had been established and quantified (3 days after inoculation), wounds were randomised and topically treated with either placebo-gel (carrier-control n = 7), 0.1 % linezolid (n = 3), 0.1 % mupirocin (n = 3), 2 % mupirocin (commercial ointment; n = 4) or 0.1 % moxifloxacin (n = 7). Topical treatment and wound fluid collection was carried out every other day for 2 weeks for quantitative bacterial analysis to monitor wound infection. Animals were photographed every day to document macroscopic signs of infection. The animals were sacrificed 21 days post-inoculation and tissue biopsies were taken for histological analysis and quantitative bacterial counts. Results: No macroscopic difference was seen between the active treatment groups, whereas pus accumulation was seen in the carrier control group. Pre-treatment all wounds showed a high and stable bacterial infection (> 105 cfu/ml wound fluid). Antibiotic therapy with linezolid, mupirocin and moxifloxacin significantly reduced bacterial counts in wound fluid and tissue in contrast to the carrier control. Moxifloxacin showed a strong antimicrobial activity (with up to 103 reduction in bacterial counts) compared to carrier control (fluid p = 0.012, tissue p = 0.013). Linezolid and mupirocin showed comparable results. Conclusion: All antibiotics showed high efficacy towards MRSA infection in this porcine full-thickness wound infection model. The activity of moxifloxacin is comparable to that of clinically used antibiotics (linezolid, mupirocin) and no side effects were observed. Moxifloxacin has promise to be a potential new therapeutic option for the treatment of MRSA wound infection.