Macrolides erythromycin

Clarithromycin is a derivative of erythromycin (macrolide). Advantages over erythromycin include lower frequency of gastrointestinal side-effects and lower dosage frequency. Clarithromycin is administered every 12 hours. As with all macrolides it should be used with caution in patients who are at risk of developing QT interval prolongation caused either by electrolyte imbalances or the concomitant use of other drugs. 

Flurithromycin (120), a fluorinated erythromycin macrolide, has been isolated from a mutant strain of Streptomyces erythraeus. It shows antibacterial activity against Streptococcus pneumoniae (MIC 0.0015-... 

The performance of HSCCC-ESI-MS was evaluated by analyzing erythromycins and didemnins [10]. Because erythromycins (macrolide antibiotics) show weak UV absorbance and cannot be detected easily with a conventional UV detector, mass spectrometric detection is a very useful technique for analysis of these antibiotics. A mixture of erythromycin A (Er-A,... 

Erythromycin was discovered in 1952 in the metabolic products of a strain of Streptomyces erythreus. Clarithromycin and azithromycin are semisynthetic derivatives of erythromycin. Macrolide antibiotics contain a many-membered lactone ring (14-membered rings for erythromycin and clarithromycin, and a 15-membered ring for azithromycin) to which are attached one or more deoxy sugars. Clarithromycin differs from erythromycin only by methylation of the hydroxyl group at the 6 position, and azithromycin differs by the addition of a methyl-substituted... 

Erythromycin Macrolide antibiotic bacteriostatic inhibitor of protein synthesis (50S) activ-... 

The performance of HSCCC-ESI-MS was evaluated by analyzing erythromycins and didemnins. ° Because erythromycins (macrolide antibiotics) show weak UV absorbance and cannot be detected easily with a conventional UV detector, mass spectrometric detection is a very usefiil technique for analysis of these antibiotics. A mixture of erythromycin A (Er-A, MW 733), erythromycin estolate (Er-E, MW 789), and erythromycin ethyl succinate (Er-S, MW 789) was analyzed using HSCCC-ESI-MS with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (4 7 4 3). TIC showed, clearly, four peaks corresponding to Er-A, Er-E, Er-S, and an unknown substance. The mass spectra of Er-E and Er-S gave [M -f H]+ at miz 862 and 789 and [M - - H - H2O] at mIz 844 and 772, respectively. In the mass spectmm of Er-A, [M -I- H - H20] was observed at miz 761 however, no [M + H] was given. The mass spectrum of the unknown peak indicated that it consists of two components with molecular weights of 843 and 772, which correspond to dehydrated Er-S and Er-E, respectively. 

The University of Idaho and USFWS, with funds from the Bonneville Power Administration, are also gathering data for registration of erythromycin. Erythromycin is intended for control of bacterial kidney disease in salmonid fingerlings that can also be transmitted by broodstock to the eggs (9). If research is completed on schedule and data indicate that the compound is safe and effective, registration is scheduled for 1994 (see Antibiotics, MACROLIDES). 

Many natural products are lactones, and it is not unusual to find examples in which the ring size is rather large. A few naturally occuning lactones are shown in Figure 19.8. The macrolide antibiotics, of which erythromycin is one example, are macrocyclic (large-ring) lactones. The lactone ring of erythromycin is 14-membered. 

The fungus Streptomyces erythreus is the source of a number of structurally related macrolide antibiotics that are collectively known as the erythromycins. The erythromycins occupy a prominent position in medicine by virtue of their useful antibacterial properties. Their use in therapy over the course of the last three decades has been widespread, and has resulted in the saving of many human lives. In this chapter, we address the landmark total synthesis of erythronolide B (1), the biosynthetic precursor of all the erythromycins, by E.J. Corey and his coworkers which was carried out at Harvard in the 1970s.1... 

Another group of antibiotics that can be inactivated by hydrolysis are 14- and 15- membered macrolides [2]. Esterases cleave the lactone ring. The plasmid encoded ere genes are found in members of the Enter-obacteriaceae and increase the intrinsic resistance. Furthermore, these esterases can also be found in some isolates of erythromycin resistant staphylococci. 

The lincosamides, another group of anti-infectives, are effective against many gram-positive organisms, such as streptococci and staphylococci. However, because of their high potential for toxicity, the lincosamides are usually used only for the treatment of serious infections in which penicillin or erythromycin (a macrolide) is not effective... 

The results showed that the compounds studied with more frequency in the aquatic environment, and of which, logically, there is more information, are the antibiotics, analgesics and anti-inflammatories (like diclofenac, ibuprofen, naproxen, acetylsalicylic acid, and paracetamol), as well as the p-blocker atenolol. In the category of antibiotics, several families are included, like the macrolides (erythromycin), the fluoroquinolones (ofloxacin and ciprofloxacin), sulfonamides (sulfamethoxazole), penicillins (amoxicillin), the metronidazol, and trimethoprim. Other therapeutic groups also widely studied and frequently found in the environmental waters are the lipid regulators (gemfibrozil and bezafibrat), antiepileptic carbamaze-pine, and antidepressants (diazepam, fluoxetine, paroxetine) (see Table 3). 

Fig. 5.11 Erythromycins erythromycin is a mixture of macrolide antibiotics consisting largely of erythromycin A.

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