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Tetracycline

Tetracyclines are produced by various Streptomyces strains and are extensively applied in human and veterinary medicine. They display a broad spectrum of antimicrobial activity in combination with low toxicity and can be applied orally. The most commonly prescribed tetracycline drugs are tetracycline itself and oxytetracydine, an oxygenated derivative, which are directly isolated from fermentation liquors, and doxycycline whose partial synthesis from oxy- [Pg.316]

X H doxycycline a vibramycin (more stable artificial derivative) [Pg.317]

The numbering system of tetracyclines is used for synthetic intermediates. [Pg.318]

Tetracyclines are classified as broad-spectrum antibiotics obtained from soil acti-nomycetes. All tetracyclines are slightly bitter solids and are weakly soluble in water. Although tetracyclines develop organism resistance, they are the drugs of first choice in venereal disease, atypical pneumonia, cholera, brucellosis, and plague. Tetracyclines also are used in urinary tract infections, amebiasis, acne, and as prophylaxis against meningitis. [Pg.292]

Tetracyclines should not be used during pregnancy, lactation, or in children. They should be used cautiously in patients with renal and hepatic insufficiency. The drug should never be used after the expiration date, as it becomes toxic. Tetracyclines should not be administered along with milk, as it chelates calcium. [Pg.292]

The tetracyclines as a whole have a broad spectrum of activity and are the most widely prescribed form of antibiotic after penicillins. They are also capable of attacking the malarial parasite. [Pg.199]

Chlortetracyclin inhibits protein synthesis by binding to the 30S subunit of ribosomes and prevents the aminoacyl-tRNA binding to the A site on the ribosome. This prevents the codon-anticodon interaction from taking place. Protein release is also inhibited. [Pg.200]

There is no reason why tetracyclines should not attack protein synthesis in mammalian cells as well as in bacterial cells. In fact, they can. Fortunately, bacterial cells accumulate the drug far more efficiently than mammalian cells and are therefore more susceptible [Pg.200]

The tetracyclines (Table 1.15) are a large family of antibiotics, the first members of which were derived from the Streptomyces genus of Actinobacteria. Chlortetracycline was isolated from Streptomyces aureofaciens in 1944, and a few years later, oxytetracycline and demeclocycline were [Pg.45]

Phthalylsulfathiazole 2-[[[4-[(2-Thiazolylamino)sulfonyl]phenyl] amino]carbonyl]benzoic acid [Pg.46]

Tetracyclines are broad-spectrum antibiotics that inhibit protein synthesis—a mechanism that involves reversible binding of the drug to receptors of the 305 ribosomal subunit of susceptible organisms. This, in turn, blocks binding of the aminoacyl-tRNA to the acceptor site on the mRNA-ribosomal complex and prevents the addition of new amino [Pg.49]

Resistance to tetracyclines is conferred on bacteria by at least three mechanisms. One mechanism involves the efflux of tetracyclines from bacterial cells and is the [Pg.49]

12aS )-4-(Dimethylamino)-3,5,10,12,12a-pentahydroxy-6-methyl-1,11-dioxo-1,4,4a,5,5a,6,11,12a-octahydrotetracene-2-carboxamide [Pg.50]

In general, the tetracyclines are yellow crystalline compounds that have amphoteric properties (Fig. 2) (15). They are soluble in both aqueous acid and aqueous base. The acid salts tend to be soluble in organic solvents such as 1-butanol, dioxane, and 2-ethoxyethanol. In fact, 1-butanol is used to extract the salts from aqueous solution. [Pg.177]

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) [Pg.177]

The tetracyclines are strong chelating agents. Both the A-ring and 11,12 p-diketone systems are active sites for chelation (16). This ability to chelate to metals, such as calcium, results in tooth discoloration when tetracycline is administered to children (17). [Pg.178]

Each tetracycline possesses a characteristic uv-absorption spectrum and this property is used extensively in structure elucidation (12,13). This spectmm results from the contribution of two chromophores the BCD ring system gives a Xmax at approximately 350 nm and the A-ring a max at approximately 265 nm. [Pg.178]

The tetracycline molecule (1) presents a special challenge with regard to the study of structure—activity relationships. The difficulty has been to devise chemical pathways that preserve the BCD ring chromophore and its antibacterial properties. The lability of the 6-hydroxy group to acid and base degradation (12,13), plus the ease of epimerization (23) at position 4, contribute to chemical instability under many reaction conditions. [Pg.178]

In food-producing animals, tetracyclines can be administered orally through feed or drinking water, parenterally, or by intramammary infusion. However, oral administration suppresses initially die ruminal fermentation of plant fiber. The absorption of tetracyclines can be further adversely affected by the presence of metallic ions in the gastrointestinal tract. All tetracyclines have an affinity for metallic ions and should not be administered with milk or high calcium levels in feed unless an upward adjustment in the dosage is made (226-228). [Pg.95]

Tetracyclines are rapidly but moderately absorbed from the gastrointestinal tract. The degree of oral absorption of the various tetracyclines is also a function of the lipophilicity of the particular compound. The least lipophilic oxytetracycline is the least well absorbed and the most lipophilic doxycycline is the best absorbed, whereas the absorption of the other tetracyclines falls between these two extremes. [Pg.95]

Some of the administered dosage is concentrated in liver, excreted in bile, and reabsorbed from the intestines so that a small amount may persist in the blood for a long time after administration, due to enterohepatic circulation. The persistence of tetracyclines in the blood following absorption is a surprising contrast to other antibiotics that are eliminated more rapidly. Some absorption of tetracyclines into the bloodstream may also occur following intramammary infusion. [Pg.95]

They undergo minimal or no metabolism and they are excreted in urine and feces either unchanged or in a microbiologically inactive form. Although there have been differences among individual tetracyclines as to their urinary and fecal excretion, these differences are not substantial. Tetracyclines are also eliminated in milk (233), attaining approximately 50-60% of the plasma concen- [Pg.96]

Oxytetracycline has a long history in human and veterinary medicine for the treatment and control of a wide variety of bacterial infections, and for its growth-promoting properties. It may be administered by any of the normal routes. It is readily absorbed from the intestine by most mammals but intestinal absorption in poultry is restricted. Oxytetracycline is most useful in that it readily disperses throughout the body, attaining therapeutic levels in most tissues and fluids within a short time. [Pg.97]

The stereochemistry uf the tetracyclines is very complex. Carbon atoms 4. 4a.. S.. Na. 6. and 12a arc potentially chiral, depending on substitution. Oxytctracyclinc and doxycyclinc. each with a Sa-hydroxyl substituent, have six asymmetric centers the others, lacking chirality at C-. . have only five. Determination of the complete, absolute stcreochemi.stry of the tetracyclines w.as a difficult problem. Detailed x-ray diffraction analysis c.siablished the stereochemical formula shown in Table 10-6 as the orientations found in the natural and semisynthetic tetracyclines. Tlic.se studies also confirmed that conjugated systems exist in the structure from C-10 through C-12 and from C-1 through C-.T and that the formula represents only one uf. several canonical forms exi.st-ing in those portions of the molecule. [Pg.341]

The tetracyclines are amphoteric compounds. I urming salts with either acids or buses. In neutral solutions, these sub- [Pg.341]

The unusual structural groupings in the tetracyclines produce three acidity constants in aqueous. solutions of the acid salts (Table l()-7). The particular functional groups re.sponsi-ble for each of the themiodynamic pK values were determined by Leeson ct ul. - as shown in the diagram below. These groupings hud been identified previously by Stephens et ul. us the sites for protonution. hut their curlier ussign-ments, which produced the values responsible for pK and [Pg.342]

The approximate pK, values for each of these groups in the six tetracycline salts in common use arc shown (Table 10-7). The values are taken from Stephens et al.. Bcnci and Goyan. - and Barringer et al. The pK of the 7-diniethylumino group of minocycline (not listed) is 5.0. [Pg.342]

Stable chelate complexes are formed by the tetrucyclino with many metals, including calcium, magnesium, and inm. Such chelutes arc usually very insoluble in water. accounUD for the impaired absorption of most (if not all) tetracyclino [Pg.342]

Although no new halogen-containing tetracyclines have been reported since the first survey (1), the gene responsible for the chlorination of tetracycline in Streptomyces aureofaciens (Fig. 3.24) has been cloned and the sequence of nucleotides determined (1651). The gene product is a 452 amino acid chlorination enzyme. [Pg.253]

What are the adverse effects associated with the tetracyclines  [Pg.115]

Chlamydia trachomatis is the primary cause of nongonococcal urethritis, followed by Ureaplasma urealyticum. Doxycycline is the tetracycline of choice for the treatment of nongonococcal urethritis because it has activity against both organisms. There are three tetracyclines that are primarily used for the treatment of infections tetracycline, doxycy- [Pg.115]

Doxycycline can cause nausea, vomiting, and diarrhea. The bioavailability of doxycycline is reduced if coadministered with multivalent ions such as iron or magnesium. However, unlike tetracycline, it can be administered with food and dairy products. In addition, patients taking tetracyclines may experience photosensitivity, especially if they are fair skinned. Patients taking tetracyclines should avoid prolonged exposure to sunlight. [Pg.115]

Case Condasion VD. s started on doxycycline for 7 days. The patient is instructed to avoid prolonged exposure to sunlight and to avoid concomitant dosing wi antacids or any othw medications that may contain muitivalem cations. [Pg.115]

Clinical usage Tetracylines are effective for sexually transmitted diseases caused by chlamydia and syphilis. They are also commonly used for the treatment of community-acquired pneumonia, Lyme disease, and Rocky Mountain spotted fever, and in combination with other agents for Helicobacter pylori. [Pg.116]

The epoch-making discovery of chlortetracycline (aureomycin) in 1947 by Duggar paved the way for a number of structural analogues used as broad-spectrum antibiotics that belong to the tetracycline family. The tetracyclines which are found to be effective therapeutically are listed in the following table. [Pg.772]

Name of Compound Official Status Brand Name(s) Rj Rj Rj R4 Rg  [Pg.772]

Based on the above eonventional numbering of various earbon atoms and subsequent labelling of the four aromatie rings present in the tetracycline nucleus, oxytetracycline is chemically designated as  [Pg.772]

Some other members of the tetracycline family may conveniently be named as follows Methacycline 6-Methylene-5-oxytetracycline  [Pg.773]

Tetracycline and tetracycline derivatives (see Table 33-3) inhibit protein synthesis by binding to several components of the ribosomal apparatus in susceptible bacteria.3,12 Hence, these drugs may cause misreading of the mRNA code, as well as impair the formation of peptide bonds at the bacterial ribosome. Thus, tetracyclines are very effective in preventing bacterial protein synthesis. [Pg.508]

Some of the newer tetracycline derivatives such as doxycycline may be used to overcome bacterial strains that are resistant to the traditional drugs.16 Currently, tetracyclines are used to treat specific infections relating to such bacilli as Chlamydia, Rickettsia, and certain spirochetes (see Table 33-5). Tetracyclines may also be used as alternative agents in treating bacterial strains [Pg.508]

Tetracyclines also seem to have anti-inflammatory and immunomodulating effects.53,71 Although the exact reasons for these effects are unclear, tetracyclines have been used in a variety of noninfectious diseases with an inflammatory or autoimmune basis, including scleroderma and rheumatoid arthritis.71 Clinical studies will continue to investigate how these drugs can be used effectively in the long-term management of chronic disease. [Pg.509]

Gastrointestinal distress (nausea, vomiting, diarrhea) may be a problem with tetracycline use. Hypersensitivity reactions (such as rashes) may also occur, as well as an increase in skin sensitivity to ultraviolet light (photosensitivity).16 Tetracyclines form chemical complexes with calcium that may impair the growth and development of calcified tissues such as bone and teeth, especially in children.69 Tetracyclines also cause discoloration of teeth in children and pregnant women, apparently because of the tetracycline-calcium interaction.69 As mentioned previously, development of tetracycline-resistant strains and resulting superinfections may be a serious problem during tetracycline therapy. [Pg.509]

The first tetracycline discovered was produced by a soil organism, Streptomyces aureofiaciens and is now known as chlortetracycline [57-62-5] (2), [Pg.177]

These have a wide range of activity against gram positive and gram negative bacteria and against large viruses. [Pg.573]

Layer Silica gel G (Firm 88) a mixture of 30 g silica gel G + 9 g di-Na EDTA + 60 ml water used with solvents 22, 27 and 28 [20]. [Pg.573]

Radial (circular) technique has been employed as well as the usual procedure [20, 42]. Two or three chromatographic runs on the same layer have been recommended for better separation of tetracycline and 6-demethyltetracycline [42] the layer is dried between each run. [Pg.573]

Most of the substances fluoresce yellow-green in UV light ammonia vapour intensifles the fluorescence. [Pg.573]

Spraying with a 50 % solution of SbClg in acetic acid and then heating 5—10 min at 110° G Tc, Cl-Tc and 6-demethyl-Tc then appear as reddish spots in daylight and brick red in UV light oxy-Tc is yellow in daylight and blue in UV light. [Pg.573]

Tetracycline Oxytetracycline Doxy cy dine Demeclocycline Minocycline [Pg.187]


Erythromycin is active against gram-positive and certain gram-negative bacteria, also against Rickettsia and spirochaetes. It is used for patients who are allergic to or do not respond to treatment with penicillins or tetracyclines. [Pg.162]

M.p. 296 C. Accepts an electron from suitable donors forming a radical anion. Used for colorimetric determination of free radical precursors, replacement of Mn02 in aluminium solid electrolytic capacitors, construction of heat-sensitive resistors and ion-specific electrodes and for inducing radical polymerizations. The charge transfer complexes it forms with certain donors behave electrically like metals with anisotropic conductivity. Like tetracyanoethylene it belongs to a class of compounds called rr-acids. tetracyclines An important group of antibiotics isolated from Streptomyces spp., having structures based on a naphthacene skeleton. Tetracycline, the parent compound, has the structure ... [Pg.389]

The 7-chloro-derivative, the first of the group to be isolated (1948) is known as chlortetracy-cline. The 5-hydroxy-derivative is oxytetracy-dine. More recently introduced tetracyclines are 6-demethyl-7-chlorotetracycline and 5-hydroxy-6-deoxy-6-methyienetetracycline. [Pg.390]

Tetracyclines are broad-spectrum antibiotics. effective against Gram-positive and Gram-negative bacteria, also against Rickettsiae (typhus fever) and certain other organisms. [Pg.390]

Figure 7-15 shows the time evolution of the temperature, total energy, and potential energy for a 300 ps simulation of the tetracycline repressor dimer in its induced (i.e., hgand-bound) form. Starting from the X-ray structure of the monomer in a complex with one molecule of tetracycline and a magnesium ion (protein database... [Pg.369]

Figure 7-16. Superimpasition of the X-ray structure of the tetracycline repressor class D dimer (dark, protein database entry 2TRT) with the calculated geometrical average of a 3 ns MD simulation (light trace). Only the protein backbone C trace Is shown, The secondary structure elements and the tertiary structure are almost perfectly reproduced and maintained throughout the whole production phase of the calculation,... Figure 7-16. Superimpasition of the X-ray structure of the tetracycline repressor class D dimer (dark, protein database entry 2TRT) with the calculated geometrical average of a 3 ns MD simulation (light trace). Only the protein backbone C trace Is shown, The secondary structure elements and the tertiary structure are almost perfectly reproduced and maintained throughout the whole production phase of the calculation,...

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Tetracyclin

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