Demethylchlortetracyclin

Similarly, by adding analogs of L-methionine, the methylation of C6 is inhibited, resulting in the formation of 6-demethylchlortetracycline. The analogs that may be used include D-methionine and ethionine. 

Fig. 5.7 Tetracycline antibiotics 1, oxytetracycline 2, chlortetracycline 3, tetracycline 4, demethylchlortetracycline 5, doxycycline 6, methacycline 7, clomocycline 8, minocycline 9, thiacycline (a thiatetracycline with a sulphur atom at 6).

The microorganism is again P. chrysogenum. A manufacturer may use the same mutant strain to make both products or may have different mutants for the two penicillins. Parallel situations of a single organism producing more than one natural product occur with other types of antibiotics, for example strains of Streptomyces aureofaciens are used for both chlortetracycline and demethylchlortetracycline fermentations. 

Demethyl-6-deoxytetracycline, 24 600 6-Demethylchlortetracycline, 24 592 Demigras coal grade (France), 6 713t Deminerahzation water softening method, 26 122, 123... 

Administration of 100 mg doxycycline, in the absence of foods, led to almost complete absorption from the gut and a peak blood level of 1-8 Mg/ml two hours after ingestion. Three times this dose was required.to produce a similar blood level in four hours in the case of 300 mg demethylchlortetracycline. The plasma half-life (after single dose) was 15 hours in the case of doxycycline and 12 hours for demethylchlortetracycline. This means that the half-life of doxycycline is seven hours longer than that of tetracycline. 

The presence of tetracyclines in urine and plasma can be readily and sensitively determined (321). Doxycycline, tetracycline, oxytetracycline, demethylchlortetracycline, and jnethacycline analyses were found to be highly sensitive to the pH of the medium (322). Determination of amino-... 

Fig. 29.8.1 Chromatograms of a blank kidney sample (A), a kidney sample (B) fortified with 4 ppm of oxytetracycline (—), and 250 ppb of each tetracycline (—), and ultraviolet spectra (C) of the corresponding tetracyclines. Peaks OTC, oxytetracycline TC, tetracycline DMTC, demethylchlortetracycline CTC, chlortetracycline MC, methacycline DC, doxycycline. (From Ref. 296.). 

The addition of NaBr to the medium leads to the production of a brominated derivative (bromotetracycline) (7) instead of the chlorinated one [17]. Other chlortetracyclines such as demethylchlortetracycline (8) [18] or... 

Synonyms. Demethylchlortetracycline DMCT. Proprietary Name. Ledermycin (drops and syrup) 7-Chloro-6-demethyltetracycline C2iH2,C1N208 = 464.9 CAS—127-33-3... 

Miyazaki, S. Nakano, M. Arita, T. A comparison of bioavailability of free bases and hydrochloride salts of chlorte-tracycline, demethylchlortetracycline, and methacycline. 

Pollen RH. Anaphylactoid reaction to orally administered demethylchlortetracycline. N Engl J Med 1964 271 673. 

The possible effects of such modifications are of several kinds, some not directly concerned with therapeutic efficacy. In its new form the antibiotic may be more stable, more soluble, more palatable (chloramphenicol palmitate), better absorbed (erythromycin estolate), or less irritant to the tissues (polymyxin methane sulfonate). Some of the most far-reaching effects produced by a minor structural change are seen in demethylchlortetracycline, which, as compared with tetracycline, is more stable, antibacterially more active, and much more slowly excreted. 

Extracted chlortetracycline, demeclocycline (demethylchlortetracycline), do grcycline, methacycline, minocycline, oxytetracycline... 

Extracted chlortetracycline, demethylchlortetracycline, dojycycline, methacycline, oxytet-racycline... 

Demethylchlortetracycline hydrochloride Erythromycin ethylsuccinate Erythromycin stearate Erythromycin sulfate Gentamicin sulfate Hydrabamine penicillin V Hygromycin B... 

The most important drugs with sensitizing effects are listed in Table 4. Tetracyclines, in particular demethylchlortetracycline, are commonly responsible for photodermatitis. However, this action does not have any immunological basis, but depends on a phototoxic effect (Harder et al. 1961 Maibach et al. 1967), similar to that produced by psoralens, certain dyes, cadmium sulphide, etc. 

The tetracyclines are a group of antibiotics with the same basic chemical structure they are derivatives of the naphthacene ring system. Compounds of the series differ in the composition of the side chains (Fig. 1). These antibiotics derived from different Streptomyces species show closely related spectra of bacteriostatic properties, with the exception of minocycline, which is very effective against most Staphylococcus strains resistant to other tetracyclines. Absorption, metabolism, and excretion of the different tetracyclines vary, however. After oral application, tetracycline, oxytetracycline, and chlortetracycline are absorbed to a much lesser degree than demethylchlortetracycline, methacycline, or the almost entirely absorbed minocycline. Maximum blood levels are found 2-6 h after oral intake and immediately in the case of intravenous infusion. Half-lives between 8 and 15 h were reported. The tetracyclines diffuse readily across the vascular barrier and are found in various tissues such as the liver, spleen, bone marrow, kidney, skin, and lungs as well as the peritoneal and pericardiac cavities. The tetracyclines are also able to... 

Fig. 1 a-h. Chemical structures of the tetracyclines, a tetracycline b oxytetracycline c chlortetracycline d methacycline e demethylchlortetracycline f 6-deoxytetracycline (doxycycline) g minocycline h roli(A -pyrrolidinomethyl)tetracycline... 

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