Tetracyclines oxytetracycline

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-... 

Tetracyclines have been marketed since 1984, and, since discovery, some first-generation tetracyclines such as tetracycline, oxytetracycline, and chlorotetracychne have been extensively used in livestock and aquaculture, besides clinical use by humans. For human use, the second-generation tetracyclines doxycycline and minocycline have been prescribed to a great extent, and indeed prescription of the latter has steadily increased in the United States over the 2003-2005 period (Fig. 1.7). However, each of these tetracyclines is less than 0.5% of all the other 200 most prescribed dmgs. Tetracyclines are also prescribed to a good extent in several European countries (Fig. 1.6), with the exception of Italy and Denmark where per capita prescriptions are quite minimal, that is, <25 prescriptions per 1000 inhabitants (Molstad et ah, 2000). They are also widely used in animal husbandry where daily therapeutic doses of 40 mg tetracycline kg liveweight are typical (Kilhne et al., 2000). 

Tetracyclines mainly differ in their absorption after oral administration and their elimination. Absorption after oral administration is approximately 30% for chlortetracycline 60-70% for tetracycline, oxytetracycline, demeclocycline, and methacycline and 95-100% for doxycycline and minocycline. Tigecycline is poorly absorbed orally and must be administered intravenously. A portion of an orally administered dose of tetracycline remains in the gut lumen, modifies intestinal flora, and is excreted in the feces. Absorption occurs mainly in the upper small intestine and is impaired by food (except doxycycline and... 

Tetracyclines are classified as short-acting (chlortetracycline, tetracycline, oxytetracycline), intermediate-acting (demeclocycline and methacycline), or long-acting (doxycycline and minocycline) based on serum half-lives of 6-8 hours, 12 hours, and 16-18 hours, respectively. Tigecycline has a half-life of 36 hours. The almost complete absorption and slow excretion of doxycycline and minocycline allow for once-daily dosing. 

Quantification and confirmation of tetracycline, oxytetracycline, and chlortetracycline residues in milk (84) as well as chloramphenicol residues in calf muscle (85) have been also carried out using LC-PB-NCI-MS. Use of an SIM mode allowed a detection limit of about 100 ppb for the tetracyclines and 2 ppb for chloramphenicol residues. 

Alternative sample extraction techniques include an approach that combines the deproteinizing efficiency of dichloromethane with the ion-pairing ability of phenylbutazone for isolating tetracyclines from eggs (308). Another approach that was employed for extracting oxytetracycline from milk (285) or swine tissues (309), and tetracycline, oxytetracycline, and chlortetracycline from milk (284), was based on ultrafiltration. With ultrafiltration, however, not all low molecular-mass proteins are retained in the cut-off filters while interfering substances pass through the filter. 

Ultrafiltration (278, 279) and immunoaffinity chromatography (282) have also been described for removal of matrix components from milk extracts, while online trace enrichment has been reported for isolation/purification of tetracycline, oxytetracycline, demeclocycline, and chlortetracycline residues from animal tissues and egg constituents (305). The latter technique involves trapping of the analytes onto a metal chelate affinity preconcentration column (Anagel-TSK Chelate-5PW), rinsing of coextracted materials to waste, and finally flushing of the concentrated analytes onto the analytical column. 

WJ Blanchflower, RJ McCracken, AS Haggan, DG Kennedy. Confirmatory assay for the determination of tetracycline, oxytetracycline, chlortetracycline and its isomers in muscle and kidney using liquid chromatography-mass spectrometry. J Chromatogr B 692 351-360, 1997. 

A.M. Kamel, P.R. Brown, B. Munson, ESI-MS of tetracycline, oxytetracycline, chlorotetracycline, minocycline, andmethacycline. Anal. Chem., 71 (1999) 968. 

Tetracycline was discovered after a team of workers examined 100000 soil samples from around the world. Tetracycline derivatives include chlor-tetracycline, oxytetracycline, doxycycline and minocycline. The tetracyclines have a broad spectrum of activity they are effective against Grampositive and Gram-negative bacteria, some anaerobes. Chlamydia, Mycoplasma, Ehrlichia and Rickettsia spp. and some protozoa. Their activity against staphylococci is usually limited and they are not active against enterococci. E. coli, Klebsiella, Proteus and Pseudomonas spp. are usually resistant. Doxycycline and minocycline are usually more active in vitro than the other tetracyclines. Differences in the clinical efficacy of the tetracyclines can be attributed to differences in the absorption, distribution and excretion of the individual drugs rather than to differences in bacterial susceptibility. 

Oral antibacterials these can be prescribed If topical therapy alone Is Ineffective. Tetracycline, oxytetracycline, doxycycline, minocycline, lymecycline, erythromycin and trimethoprim are the agents used. Treatment is long-term - for up to 2 years. 

Theileriasis Theileria spp. Tetracyclines (oxytetracycline, chlor-tetracycline, rohtetracycline), menoc-tone, BW-993C (clexon), BW-720C (buparvaquone), halofuginone lactate. 

Anaplasmosis Anaplasma spp. Tetracycline, oxytetracycline, chlortetracycline, imidocarb dipropionate, gloxazone. 

Chloramphenicol eye drops should be used to prevent infection. A number of different antibiotics were used in different centres by physicians managing Iranian chemical warfare casualties. These included chloramphenicol, tetracycline, oxytetracycline, bacitracin and polymyxin B. No conclusions regarding the most effective drug could be drawn. There seems little reason to abandon the use of chloramphenical eye drops. 

Demeclocycline, tetracycline, oxytetracycline, minocycline, and doxycycline are available in the United States for systemic use. Chlortetracycline and oxytetracycline are used in ophthalmic preparations. Methacycline is not available. Other derivatives are available in other countries. The more lipophilic drugs, minocycline and doxycycline, usually are the most active by weight, followed by tetracycline. Resistance of a bacterial strain to any one member of the class may result in cross-resistance to other tetracyclines. Bacterial strains with tetracycline minimum inhibitory concentrations (MICs) of < 4 pg/mL are considered susceptible... 

The absorption of tetracyclines from the G1 tract is non-uniform. Up to 30% of chlortetracycline is absorbed. The absorption for tetracycline, oxytetracycline, and demeclo-cycline ranges between 60 and 80%, whereas as much as 90 to 100% of doxycycline and minocycline is absorbed. The absorption of tetracyclines is impaired by divalent cations (calcium, magnesium, and ferrous iron), by aluminum, and by extremely alkaline pHs. Tetracyclines are distributed widely throughout the body fluid, cross the placental barrier, and can accumulate in growing bones. The concentrations of chlortetracycline in spinal fluid are only one fourth of those in plasma. Minocycline, a more lipid-soluble tetracycline, reaches a high concentration in tears and saliva and can eradicate the meningococcal carrier state. The tetracyclines are metabolized in the liver and excreted mainly by the bile and urine. The concentrations of tetracyclines in the bile are ten times higher than those in serum. 

ROUTES OF ADMINISTRATION AND DOSAGE A variety of tetracyclines are available for oral, parenteral, and topical administration. Tetracycline, oxytetracycline (TERRAMYCIN, others), demeclocycline (declomycin), minocycline (minocin, others), and doxycycline (vibramycin, others) are available in the U.S. 

A group ADI for tetracycline, oxytetracycline, and chlortetracycline has been allocated by JECFA. The CAC has also established MRLs for tetracycline, oxytetracycline and chlortetracycline applicable to cattle, sheep, pigs, and poultry and to flsh and giant prawn for oxytetracycline only." JECFA has prepared a number of reviews detailing residue studies on tetracyclines that support the development of the MRLs adopted by the... 

Roestel B, Tetracycline, oxytetracycline and chlortetracycline, in Residues of Some Veterinary Drugs in Animals and Foods, FAO Food and Nutrition Paper 41/11, 1998, p. 23 (available at ftp //ftp.fao.org/ag/agn/ jecfa/vetdrug/41-ll-chlortetracYcline oxytetra cycline tetracycline.pdf accessed 11/23/10). 

Stolker et al. " described an analytical method based on TFC-LC-MS/MS for the direct analysis of 11 veterinary drugs (belonging to seven different classes) in milk. The method was applied to a series of raw milk samples, and the analysis was carried out for albendazole, difloxacin, tetracycline, oxytetracycline, phenylbutazone, salinomycin-Na, spiramycin, and sulfamethazine in milk samples with various fat contents. Even without internal standards, results proved to be linear and quantitative in the concentration range of 50-500 (xg/1, as well as repeatable (RSD<14% sulfamethazine and difloxacin <20%). The limits of detection were between 0.1 and 5.2 xg/l, far below the maximum residue limits for milk set by the EU. While matrix effects, namely, ion suppression or enhancement, were observed for all the analytes, the method proved to be useful for screening purposes because of its detection limits, linearity, and repeatability. A set of blank and fortified raw milk samples was analyzed and no false-positive or falsenegative results were obtained. 

Eritz J, Zuo Y, Simultaneous determination of tetracycline, oxytetracycline, and 4-epitetracycline in milk by high performance liquid chromatography. Food Chem. 2007 107 1297-1301. 

Only tetracycline, oxytetracycline, methacycline, minocycline and doxy-cycline have been shown to interact with iron, but it seems reasonable to expect that the other tetracyclines will behave in a similar way. 

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... 

Although CDs are generally used in the mobile phase as additives to improve separation, their application as extracting agent and sensitivity enhancer of the detection was also reported. Thus, a saturated solution of (3-CD was employed for the extraction of five polycyclic aromatic hydrocarbons (PAHs) from environmental samples. The application of (3-CD enhanced the efficacy of extraction and increased the sensitivity of fluorescence detection. The capacity of (3-CD to enhance the sensitivity of the chemi-luminscence detection of tetracyclines (oxytetracycline, tetracycline, and metacycline) has also been established. 

Although highly fluorescent, tetracycline antibiotics also have several electroactive moieties. The EC behavior of tetracycline, oxytetracycline, chlortetracycline... 

Tetracycline Oxytetracycline Doxy cy dine Demeclocycline Minocycline... 

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