Ampicillins Benzyl 6- -penicillinate

Davies RJ, Hendrick DJ, Pepys J. Asthma due to inhaled chemical agents ampicillin, benzyl penicillin, 6 amino peniciUanic acid and related substances. Clin Allergy 1974 4(3) 227 7. 

Penicillins. This group includes penicillin G (benzyl-penicillin), penicillin VK (phenoxymethyl-penicillin), the isoxazolyl penicillins oxacillin, cloxacillin, dicloxacillin and nafcillin, the amino-penicillins ampicillin, hetacillin and amoxycillin, the carboxy-penicil-lin carbenicillin, and the thienyl-penicillin ticarcillin. 

Penicillins and cephalosporins are charaeterized by (3-lactam structures and are the antibiotics that have traditionally been those most eommonly used in the treatment of infeetions. Pharmaceutical companies have synthesized a variety of semisynthetic (3-lactam compounds for use as oral antibiotics, for example, ampicillin and amoxieillin. These penicillin derivatives are prepared by aeylation of 6-amino-penicillanie acid (6-APA) derived from penicillin G (benzyl penicillin) or penicillin V (phenoxymethyl penicillin). An immobilized penicillin amidase (penicillin acylase) from Escherichia coli or Bacillus megaterium is used to prepare the 6-APA in nearly quantitative yield (Fig. 4). This substance is used as the starting material for the produetion of a number of other penieillins. The immobilized enzyme can be reused more than... 

Five jS-lactam antibiotics (ampicillin, cloxacillin, dicloxacillin, nafcillin, benzyl-penicillin) were isolated from milk and separated on a Cjg column (2 = 210 nm) using a 20/10/80 acetonitrile/methanol/water (50mM KH2PO4 to pH 3.5 with H3PO4) with 5 mM sodium decanesulfonate. Excellent peak shapes and resolution were obtained with complete elution in 30min [1361]. Standards were generated from 0.05 to 0.3 pg injected. Detection limits were reported as 0.1-0.35 pg/g (analyte dependent). 

Fig. 2.7 Generalized maculopapular exanthema following the introduction of amoxicillin therapy showing lesions on the trunk (a) and targeted lesions on the hands and forearms (b). The patient had positive patch tests to amoxicillin and ampicillin and negative tests to benzyl-penicillin, dicloxacUlin, and a number of cephalosporins. From Gonpalo M, in Johansen JD, Frosch PJ, Lepoittevin J-P, editors. Contact Dermatitis. 5th ed. Berlin Springer-Verlag 2011. With kind permission from Springer Science+Business Media...

The class C enzymes have Mr values of 39,000 and exhibit more uniform properties. They hydrolyse benzyl- and phenoxymethyl penicillin relatively well (turn-over numbers of 20-70 s-1), ampicillin and amoxicillin 10- to 20-fold less rapidly and extremely poorly the other penicillins (generally due to low k3 values). The early cephalosporins (cephalothin,... 

G, V, A, T, M, O, CIO at position 6 or 7 (e.g. VNH-) correspond to the side-chain of benzyl- and phenoxymethyl-penicillin, ampicillin, cephalothin, methicillin, oxacillin and cloxacillin, respectively. For their structures, see Tables 8.15 and 8.16. In addition, X at position 6 or 7 is a substituent other than an acyl substituent, e.g. halogen. 

The acylation of 6-APA with a,a-disubstituted aryl acetic acids yielded penicillins carrying a substituent on the a or benzylic carbon of the R side chain. Those of particular interest were penicillins carrying the polar -NH2 group (i.e., a-aminobenzyl penicillins) (Table 6-2, No. 13). The fact that this compound was acid stable and orally absorbed was not particularly novel (see penicillin V). Its antistaphylococcal activity was 25-60% less than that of penicillin G (the D-isomer was more active than the racemic d, l). However, its antibacterial spectrum was dramatically different. Ampicillin s spectrum, unlike previous penicillins, encompassed many important Gm- bacteria. Species of Hemophilus, Proteus, Salmonella, Shigella, and Escherichia succumbed to ampicillin. Even though resistant... 

Reactive derivatives and degradation products benzylpenicillenic acid, benzyl-penicilloic acid in aged penicillin solutions penicillin (especially ampicillin) polymers... 

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