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On Biocatalysis as Resourceful Methodology for Complex Syntheses: Selective Catalysis, Cascades and Biosynthesis
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
Andreas Sebastian Klein, Thomas Classen, Jörg Pietruszka
Phenoxymethylpenicillin (27a, penicillin V) is produced—like penicillin G (27b)—fermentative in the fungus Penicillium chrysogenum. By the supplementation of phenoxyacetate first the activated CoA-thioester 37 is formed, which competes with the natural precursor benzoyl-CoA (38) (Fig. 21.15). At high substrate concentrations, penicillin V (27a) is predominantly produced. Due to a higher acid stability, penicillin V (27a) can be given orally compared to penicillin G (27b). Penicillin V (27a) is specifically used for the treatment of bacterial infections, like streptococcal pharyngitis (strep throat), caused only by Gram-positive species. It is further less active against Gram-negative bacteria than penicillin G (27b).
Determination of antibiotics during treatment of hospital wastewater using automated solid-phase extraction followed by UHPLC-MS: occurrence, removal and environmental risks
Published in Environmental Technology, 2023
Zamazwi Lukhanyiso Mthiyane, Nkosinathi Makhubela, Hlengilizwe Nyoni, Lawrence Mzukisi Madikizela, Bethusile Rejoice Maseko, Somandla Ncube
The EICs and the assigned m/z (1+) ions for the 15 antibiotics are given in Table 1. The precursor ions for all the antibiotic analytes belonged to the [M + H]+ ion except for azithromycin and the three penicillins (amoxicillin, ampicillin and penicillin V). The precursor ion for ampicillin (m/z = 382.1434) represented the protonated methanol-adduct, while that for amoxicillin (m/z = 367.1321) represented the dihydrogen adduct. Penicillins have been reported to methanolyze in the presence of methanol forming stable protonated methanol-adducts during positive electrospray ionisation [21,22]. For penicillin V, the observed m/z of the precursor ion was related to chelating with metal ions [23–25]. The highest intensity peak for azithromycin was m/z = 716.4586, while the expected [M + H]+ ion with m/z = 749.4893 had an intensity of only 0.24%. Its spectrum has 4 quasi molecular ion peaks (Figure A2) consisting of m/z = 158.1178 (top peak), 716.4586 (2nd highest peak), 83.0493 (3rd highest peak), 558.3649 (4th highest peak) and 116.0712 (5th highest peak), all of which are common for azithromycin as presented in the PubChem website (https://pubchem.ncbi.nlm.nih.gov/compound/447043#section = MS-MS, last accessed on 05 January 2021). The discrepancies in the MS data for azithromycin have also been reported in literature [26]. The MS2 confirmation spectra for all 15 antibiotics are in Figure A.1–A.3.
Antibiotic residues in the aquatic environment – current perspective and risk considerations
Published in Journal of Environmental Science and Health, Part A, 2021
Ciaran Monahan, Rajat Nag, Dearbháile Morris, Enda Cummins
As summarized in Fig. 3, antibiotics administered in healthcare and agriculture follow a similar pathway to environmental matrices via excretion through urine or feces. Oral bioavailability describes the percentage of a compound which, when taken orally, is absorbed in the GI tract. Bioavailability varies between antibiotics, but they generally have relatively low bioavailability in both humans and animals. Within the same class, antibiotics can have significantly different rates of gastrointestinal uptake due to small differences in structure. For example, benzylpenicillin (penicillin G) has a bioavailability of roughly 30% after oral administration in humans, whereas phenoxymethylpenicillin (penicillin V) has a bioavailability of between 60-70%.[16] Due to generally high excretion rates, a large percentage of the antibiotics administered in healthcare and agriculture are excreted in feces and urine.
Critical evaluation of rate coefficients for hydroxyl radical reactions with antibiotics: A review
Published in Critical Reviews in Environmental Science and Technology, 2018
László Wojnárovits, Tünde Tóth, Erzsébet Takács
The kOH's measured by Song et al. (2008) and Dail and Mezyk (2010) by the direct pulse radiolysis technique for penicillin V, (8.76 ± 0.28) × 109 mol−1 dm3 s−1 and (8.54 ± 0.27) × 109 mol−1 dm3 s−1, respectively, agree with each-other. The k•OH of He et al. (2014), determined in H2O2 photolysis to produce •OH and competition with nitrobenzene, is somewhat smaller than the previous rate coefficients: 6.54 × 109 mol−1 dm3 s−1. We recommend to use the average, (7.95 ± 1.22) × 109 mol−1 dm3 s−1 as the k•OH of penicillin V.