Drugs online research references
Biochem J. 1975 Dec;151(3):729-39.
Synthesis of tritium-labelled isopenicillin N, penicillin N and 6-aminopenicillanic acid.
Usher JJ, Loder B, Abraham EP.
1. Phenoxymethylpenicillin sulphoxide 4-methoxybenzyl ester was labelled with 3H in its 2-beta-methyl group. Its specific radioactivity was 362 mCi/mmol. 2. Removal of the side chain of this compound yielded the corresponding ester of 6-aminopenicillanic acid sulphoxide and coupling of the latter with the appropriate protected alpha-aminoadipic acid gave 4-methoxybenzyloxycarbonylisopenicillin N sulphoxide di-4-methoxybenzyl ester or the corresponding derivative of penicillin N. 3. Removal of the protective groups by hydrogenolysis and reduction of the sulphoxide group yielded 3H-labelled isopenicillin N or penicillin N. 4. 3H-labelled phenoxymethylpenicillin sulphoxide was obtained by hydrogenolysis from its 4-methoxybenzyl ester. Reduction of its sulphoxide group and subsequent removal of the side chain gave 3H-labelled 6-aminopenicillanic acid.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=175787&dopt=Abstract
Otolaryngol Head Neck Surg. 1991 Oct;105(4):578-85.
Mucosal changes induced by experimental pneumococcal otitis media are prevented by penicillin V.
Hermansson A, Hellstrom S, Prellner K.
Department of Oto-rhino-laryngology, University of Lund, Sweden.
Penicillin V (pcV) was administered to 50 rats, either before bacterial challenge (prevention group), or after bacterial challenge but before fulminant purulent acute otitis media (AOM) was established (early treatment group). Five animals from each group were killed on days 4, 8, and 12, and 2 and 6 months after challenge. Middle ear mucosa was sampled at six different sites and studied in the light microscope. Untreated pneumococcal AOM in the rat has been shown to cause persistent structural changes of the middle ear mucosa. Both in the early treatment group and in the prevention group, the structural changes were diminished, as compared with those of untreated infected controls. The persistent structural changes seen after 6 months in untreated controls were not seen in animals that had received pcV in conjunction with the AOM episode. Though the beneficial effect on the mucosal changes during the first 2 weeks was more pronounced when pcV was given prophylactically, its use as early treatment would seem to be almost as effective in preventing the persistence of mucosal changes.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1762794&dopt=Abstract
Int J Biol Macromol. 1999 Aug;25(4):337-43.
Beta-lactam degradation catalysed by Cd2+ ion in methanol.
Martinez JH, Navarro PG, Garcia AA, de las Parras PJ.
Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Spain.
Kinetic schemes are established for degradation catalysed by Cd2+ ions in methanolic medium for penicillin G, penicillin V and cephalothin, a cephalosporin. Methanolysis of penicillin V and cephalothin occurs with the formation of a single substrate-metal ion intermediate complex, SM, while degradation of penicillin G occurs with the initial formation of two complexes with different stoichiometry, SM and S2M. In each case. degradation is of first order with respect to SM with rate constant values equal to 0.079 min(-1), 0.120 min(-1) and 0.166 min(-1) at 20, 25 and 30 degrees C, respectively, for penicillin G; 0.061 min(-1) at 20 degrees C for penicillin V; and 2.0 x 10(-3) min(-1) at 20 degrees C for cephalothin. Activation energy for the decomposition process of the SM intermediate for penicillin G was calculated to be about 5.5 x 10(4) J/mol. Equilibrium constant values between SM compound and S2M at 20 degrees C (77.1 l/mol), 25 degrees C (45.3 l/mol) and at 30 degrees C (25.7 l/mol) were also calculated as well as the normal enthalpy of this equilibrium. With respect to the reaction products there is evidence that Cd2+ becomes part of their structure, forming complexes between Cd2+ and the product resulting from antibiotic methanolysis (L). Some characteristics of these complexes are discussed.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10456774&dopt=Abstract
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