- Exploring the Biocatalytic Potential of a Self-Sufficient Cytochrome P450 from Thermothelomyces thermophila
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Among nature's arsenal of oxidative enzymes, cytochrome P450s (CYPs) catalyze the most challenging reactions, the hydroxylations of non-activated C?H bonds. Human CYPs are studied in drug development due to their physiological role at the forefront of metabolic detoxification, but their challenging handling makes them unsuitable for application. CYPs have a great potential for biocatalysis, but often lack appropriate features such as high and soluble expression, self-sufficient internal electron transport, high stability, and an engineerable substrate scope. We have probed these characteristics for a recently described CYP that originates from the thermophilic fungus Thermothelomyces thermophila (CYP505A30), a homolog of the well-known P450-BM3 from Bacillus megaterium. CYP505A30 is a natural monooxygenase-reductase fusion, is well expressed, and moderately tolerant towards temperature and solvent exposure. Although overall comparable, we found the stability of the enzyme's domains to be inverse to P450-BM3, with a more stable reductase compared to the heme domain. After analysis of a homology model, we created mutants of the enzyme based on literature data for P450-BM3. We then probed the enzyme variants in bioconversions using a panel of active pharmaceutical ingredients, and activities were detected for a number of structurally diverse compounds. Ibuprofen was biooxidized in a preparative scale whole cell bioconversion to 1-, 2- and 3-hydroxyibuprofen. (Figure presented.).
- Fürst, Maximilian J. L. J.,Kerschbaumer, Bianca,Rinnofner, Claudia,Migglautsch, Anna K.,Winkler, Margit,Fraaije, Marco W.
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p. 2487 - 2496
(2019/03/26)
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- Enrichment of Relevant Oxidative Degradation Products in Pharmaceuticals With Targeted Chemoselective Oxidation
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The ability to produce and isolate relatively pure amounts of relevant degradation products is key to several aspects of drug product development: (a) aid in the unambiguous structural identification of such degradation products, fulfilling regulatory requirements to develop safe formulations (International Conference on Harmonization Q3B and M7); (b) pursue as appropriate safety evaluations with such material, such as chronic toxicology or Ames testing; (c) for a specified degradation product in a late-stage regulatory filing, use pure and well-characterized material as the analytical standard. Producing such materials is often a resource- and time-intensive activity, either relying on the isolation of slowly formed degradation products from stressed drug product or by re-purposing the drug substance synthetic route. This problem is exacerbated if the material of interest is an oxidative degradation product, because typical oxidative stressing (H2O2 and radical initiators) tends to produce a myriad of irrelevant species beyond a certain stress threshold, greatly complicating attempts for isolating the relevant degradation product. In this article, we present reagents and methods that may allow the rapid and selective enrichment of active pharmaceutical ingredient with the desired oxidative degradation product, which can then be isolated and used for purposes described above.
- Nanda, Kausik K.,Mozziconacci, Olivier,Small, James,Allain, Leonardo R.,Helmy, Roy,Wuelfing, W. Peter
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p. 1466 - 1475
(2019/01/22)
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- Abiotic degradation and environmental toxicity of ibuprofen: Roles of mineral particles and solar radiation
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The growing medical and personal needs of human populations have escalated release of pharmaceuticals and personal care products into our natural environment. This work investigates abiotic degradation pathways of a particular PPCP, ibuprofen, in the presence of a major mineral component of soil (kaolinite clay), as well as the health effects of the primary compound and its degradation products. Results from these studies showed that the rate and extent of ibuprofen degradation is greatly influenced by the presence of clay particles and solar radiation. In the absence of solar radiation, the dominant reaction mechanism was observed to be the adsorption of ibuprofen onto clay surface where surface silanol groups play a key role. In contrast, under solar radiation and in the presence of clay particles, ibuprofen breaks down to several fractions. The decay rates were at least 6-fold higher for irradiated samples compared to those of dark conditions. Toxicity of primary ibuprofen and its secondary residues were tested on three microorganisms: Bacillus megaterium, Pseudoaltermonas atlantica; and algae from the Chlorella genus. The results from the biological assays show that primary PPCP is more toxic than the mixture of secondary products. Overall, however, biological assays carried out using only 4-acetylbenzoic acid, the most abundant secondary product, show a higher toxic effect on algae compared to its parent compound.
- Rubasinghege, Gayan,Gurung, Rubi,Rijal, Hom,Maldonado-Torres, Sabino,Chan, Andrew,Acharya, Shishir,Rogelj, Snezna,Piyasena, Menake
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- Investigations in sono-enzymatic degradation of ibuprofen
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The drug ibuprofen (IBP) appears frequently in the wastewater discharge from pharmaceutical industries. This paper reports studies in degradation of IBP employing hybrid technique of sono-enzymatic treatment. This paper also establishes synergy between individual mechanisms of enzyme and sonolysis for IBP degradation by identification of degradation intermediates, and Arrhenius & thermodynamic analysis of the experimental data. Positive synergy between sonolysis and enzyme treatment is attributed to formation of hydrophilic intermediates during degradation. These intermediates form due to hydroxylation and oxidation reactions induced by radicals formed during transient cavitation. Activation energy and enthalpy change in sono-enzymatic treatment are lower as compared to enzyme treatment, while frequency factor and entropy change are higher as compared to sonolysis. Degradation of IBP in sono-enzymatic treatment is revealed to be comparable with other hybrid techniques like photo-Fenton, sono-photocatalysis, and sono-Fenton.
- Chakma, Sankar,Moholkar, Vijayanand S.
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p. 485 - 494
(2015/11/24)
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- Degradation of ibuprofen by hydrodynamic cavitation: Reaction pathways and effect of operational parameters
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Ibuprofen (IBP) is an anti-inflammatory drug whose residues can be found worldwide in natural water bodies resulting in harmful effects to aquatic species even at low concentrations. This paper deals with the degradation of IBP in water by hydrodynamic cavitation in a convergent-divergent nozzle. Over 60% of ibuprofen was degraded in 60 min with an electrical energy per order (EEO) of 10.77 kWh m-3 at an initial concentration of 200 μg L-1 and a relative inlet pressure pin = 0.35 MPa. Five intermediates generated from different hydroxylation reactions were identified; the potential mechanisms of degradation were sketched and discussed. The reaction pathways recognized are in line with the relevant literature, both experimental and theoretical. By varying the pressure upstream the constriction, different degradation rates were observed. This effect was discussed according to a numerical simulation of the hydroxyl radical production identifying a clear correspondence between the maximum kinetic constant kOH and the maximum calculated OH production. Furthermore, in the investigated experimental conditions, the pH parameter was found not to affect the extent of degradation; this peculiar feature agrees with a recently published kinetic insight and has been explained in the light of the intermediates of the different reaction pathways.
- Musmarra, Dino,Prisciandaro, Marina,Capocelli, Mauro,Karatza, Despina,Iovino, Pasquale,Canzano, Silvana,Lancia, Amedeo
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- Photolysis and photocatalysis of ibuprofen in aqueous medium: Characterization of by-products via liquid chromatography coupled to high-resolution mass spectrometry and assessment of their toxicities against Artemia Salina
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The degradation of the pharmaceutical compound ibuprofen (IBP) in aqueous solution induced by direct photolysis (UV-A and UV-C radiation) and photocatalysis (TiO2/UV-A and TiO2/UV-C systems) was evaluated. Initially, we observed that whereas photocatalysis (both systems) and direct photolysis with UV-C radiation were able to cause an almost complete removal of IBP, the mineralization rates achieved for all the photodegradation processes were much smaller (the highest value being obtained for the TiO 2/UV-C system: 37.7%), even after an exposure time as long as 120 min. Chemical structures for the by-products formed under these oxidative conditions (11 of them were detected) were proposed based on the data from liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) analyses. Taking into account these results, an unprecedented route for the photodegradation of IBP could thus be proposed. Moreover, a fortunate result was achieved herein: tests against Artemia salina showed that the degradation products had no higher ecotoxicities than IBP, which possibly indicates that the photocatalytic (TiO2/UV-A and TiO2/UV-C systems) and photolytic (UV-C radiation) processes can be conveniently employed to deplete IBP in aqueous media. Copyright
- Da Silva, Julio Cesar Cardoso,Teodoro, Janaina Aparecida Reis,Afonso, Robson Jose De Cassia Franco,Aquino, Sergio Francisco,Augusti, Rodinei
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p. 145 - 153
(2014/02/14)
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- Preparation of human drug metabolites using fungal peroxygenases
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The synthesis of hydroxylated and O- or N-dealkylated human drug metabolites (HDMs) via selective monooxygenation remains a challenging task for synthetic organic chemists. Here we report that aromatic peroxygenases (APOs; EC 1.11.2.1) secreted by the agaric fungi Agrocybe aegerita and Coprinellus radians catalyzed the H2O2-dependent selective monooxygenation of diverse drugs, including acetanilide, dextrorphan, ibuprofen, naproxen, phenacetin, sildenafil and tolbutamide. Reactions included the hydroxylation of aromatic rings and aliphatic side chains, as well as O- and N-dealkylations and exhibited different regioselectivities depending on the particular APO used. At best, desired HDMs were obtained in yields greater than 80% and with isomeric purities up to 99%. Oxidations of tolbutamide, acetanilide and carbamazepine in the presence of H218O2 resulted in almost complete incorporation of 18O into the corresponding products, thus establishing that these reactions are peroxygenations. The deethylation of phenacetin-d1 showed an observed intramolecular deuterium isotope effect [(kH/kD) obs] of 3.1 ± 0.2, which is consistent with the existence of a cytochrome P450-like intermediate in the reaction cycle of APOs. Our results indicate that fungal peroxygenases may be useful biocatalytic tools to prepare pharmacologically relevant drug metabolites.
- Poraj-Kobielska, Marzena,Kinne, Matthias,Ullrich, Rene,Scheibner, Katrin,Kayser, Gernot,Hammel, Kenneth E.,Hofrichter, Martin
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experimental part
p. 789 - 796
(2012/07/14)
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- Phospho-ibuprofen (MDC-917) is a novel agent against colon cancer: Efficacy, metabolism, and pharmacokinetics in mouse models
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We have developed a novel chemical modification of conventional nonsteroidal anti-inflammatory drugs to reduce their toxicity and enhance their efficacy. Phospho-ibuprofen [(PI) 2-(4-isobutyl-phenyl)-propionic acid-4-(diethoxy-phosphoryloxy)-butyl ester (MDC-917)], a novel derivative of ibuprofen, strongly inhibited the growth of human colon cancer cells in vitro and SW480 human colon cancer xenografts in nude mice. PI was metabolized minimally by cultured cells, but extensively by liver microsomes and mice, undergoing regioselective oxidation to produce 1-OH-PI and carboxyl-PI, which can be hydrolyzed to 1-OH-ibuprofen and carboxyl-ibuprofen, respectively. PI also can be hydrolyzed to release ibuprofen, which can generate 2-OH-ibuprofen, carboxyl-ibuprofen, and ibuprofen glucuronide. After a single oral administration (400 mg/kg) of PI, ibuprofen and ibuprofen glucuronide are the main plasma metabolites of PI; they have, respectively, Cmax of 530 and 215 μM, Tmax of 1 and 2 h, elimination t1/2 of 7.7 and 5.3 h, and area under the concentration-time curve (0-24 h) of 1816 and 832 μM X h. Intact PI was detected in several tissues but not in plasma; at a higher PI dose (1200 mg/kg), PI plasma levels were 12.4 μM. PI generated the same metabolites in mouse plasma as conventional ibuprofen, but with much lower levels, perhaps accounting for the enhanced safety of PI. The antitumor effect of PI was significantly associated with plasma ibuprofen levels (p = 0.016) but not with xenograft ibuprofen levels (p = 0.08), suggesting a complex anticancer effect. These results provide a pharmacological basis to explain, at least in part, the anticancer efficacy and safety of this promising compound and indicate that PI merits further evaluation as an anticancer agent.
- Xie, Gang,Sun, Yu,Nie, Ting,Mackenzie, Gerardo G.,Huang, Liqun,Kopelovich, Levy,Komninou, Despina,Rigas, Basil
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experimental part
p. 876 - 886
(2012/03/27)
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