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Tetracycline distribution

Dmg distribution into tissue reservoirs depends on the physicochemical properties of the dmg. Tissue reservoirs include fat, bone, and the principal body organs. Access of dmgs to these reservoirs depends on partition coefficient, charge or degree of ionization at physiological pH, and extent of protein binding. Thus, lipophilic molecules accumulate in fat reservoirs and this accumulation can alter considerably both the duration and the concentration—response curves of dmg action. Some dmgs may accumulate selectively in defined tissues, for example, the tetracycline antibiotics in bone (see Antibiotics,tetracyclines). [Pg.269]

Table 2. Classification and Distribution of Tetracycline Resistance Determinants in Microorganisms ... Table 2. Classification and Distribution of Tetracycline Resistance Determinants in Microorganisms ...
Procedure Distribute into identical test-tubes an equal volume of standard tetracycline solution and the sample to be examined (having presumed equal concentrations) and add to each tube an equal volume of inoculated nutrient medium (for instance 1 ml of the solution and 9 ml of the medium). Prepare at the same time two control tubes without the chlortetracycline, one containing the inoculated medium and the other identical with it but treated immediately with 0.5 ml of formaldehyde solution. These tubes are used to set the optical apparatus employed to measure the growth. [Pg.288]

Figure 13.18 Replica plating for the selection of bacteria containing a recombinant vector, (a) The method used to transfer colonies of bacteria between plates, (b) Comparison of the distribution of the colonies between the plates enables identification of the colonies containing the recombinant vector. The dotted circles represent colonies that do not grow on tetracycline. Figure 13.18 Replica plating for the selection of bacteria containing a recombinant vector, (a) The method used to transfer colonies of bacteria between plates, (b) Comparison of the distribution of the colonies between the plates enables identification of the colonies containing the recombinant vector. The dotted circles represent colonies that do not grow on tetracycline.
Differences in clinical effectiveness are partly due to differences in absorption, distribution and excretion of the individual drugs. In general tetracyclines are absorbed irregularly from the gastrointestinal tract and part of the dose remains in the gut and is excreted in the faeces. However this part is able to modify the intestinal flora. Absorption of the more lipophilic tetracyclines, doxycycline and minocycline is higher and can reach 90-100%. The absorption is located in the upper small intestine and is better in the absence of food. Absorption is impaired by chelation with divalent cations. In blood 40-80% of tetracyclines is protein bound. Minocycline reaches very high concentrations in tears and saliva. Tetracyclines are excreted unchanged, in both the urine by passive filtration and in the feces. Tetracyclines are concentrated in the bile via an active... [Pg.410]

The tetracyclines are distributed throughout body tissues and fluids in concentrations that reflect the lipid solubility of each individual agent. Minocycline and doxycycline are the most lipid soluble, while oxytetracy-chne is the least hpid soluble. The tetracyclines penetrate (but somewhat unpredictably) the uninflamed meninges and cross the placental barrier. Peak serum levels are reached approximately 2 hours after oral administration cerebrospinal fluid (CSF) levels are only one-fourth those of plasma. [Pg.545]

Rhodes G., G. Huys, J. Swings, P. Mcgarm, M. Hiney, P. Smith, and R.W. Pickup (2000). Distribution of oxytetracycline resistance plasmids between aeromonads in hospital and aquaculture environments Implication of Tni 721 in dissemination of the tetracycline resistance determinant Tet A. Applied and Environmental Microbiology 66 3883-3890. [Pg.281]

The tetracyclines are widely distributed in the body and diffuse into various body fluids. [Pg.312]

After oral administration, doxycycline is rapidly and well absorbed from the gastrointestinal tract. It has a half-life of 15-22 h, which is longer than that of other tetracyclines. Following administration by various routes, doxycycline is widely distributed in the body, with highest levels in kidney and liver, besides bones and dentine. Doxycycline may be metabolized for up to 40%, and is largely excreted in feces via bile and intestinal secretion. [Pg.99]

It has been shown that lipophilic solutes permeate very slowly through membranes of Gram-negative bacteria because of the hydrophilic outer leaflet of the bacterial membranes. The dependence of rate of diffusion and the final equilibrium distribution of lipophilic drugs such as fluoroquinolones and tetracyclines which possess multiple protonation sites has been reviewed [103]. [Pg.189]

Fig. 2 Distribution of the sorted version of the P values for all reactions of the parasite for the tetracycline treatment (a) and the chloroquine treatment (b) compared with control. Each gene indexed is plotted on the /-axis and its corresponding Wilcoxon Pvalue is plotted on the y-axis... Fig. 2 Distribution of the sorted version of the P values for all reactions of the parasite for the tetracycline treatment (a) and the chloroquine treatment (b) compared with control. Each gene indexed is plotted on the /-axis and its corresponding Wilcoxon Pvalue is plotted on the y-axis...
Because there is such a wide selection available, rational choice of the necessary excipients and their concentration is required. Consideration must also be given to cost, reliability, availability, and international acceptability. Although generally considered inert, formulation incompatibility of excipients is also necessary. Lactose, for example, can react with primary and secondary amines via its aldehyde group by Maillaird condensation reaction [6], and calcium carbonate is incompatible with acids due to acid-base chemical reaction and with tetracyclines due to complexation. Additionally, excipients can contribute to the instability of the active substance through moisture distribution. [Pg.243]

Doxycycline is the preferred tetracycline because it is better absorbed and distributed than the others. [Pg.189]

Pharmacokinetics. Most tetracyclines are only partially absorbed from the alimentary tract, enough remaining in the intestine to alter the flora and cause diarrhoea. They are distributed throughout the body and cross the placenta. Tetracyclines in general are excreted mainly unchanged in the urine and should be avoided when renal function is severely impaired. Exceptionally, doxycycline and minocycline are eliminated by nonrenal routes and are preferred for patients with impaired renal function. [Pg.226]

Distribution Tetracyclines widely distribute into tissue and body fluids except CSF. [Pg.116]

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. [Pg.38]

The tetracyclines are distributed into most tissues, except the CNS (therapeutic levels may be achieved when the meninges are inflamed). Doxycycline is the most lipid-soluble tetracycline... [Pg.39]


See other pages where Tetracycline distribution is mentioned: [Pg.39]    [Pg.39]    [Pg.182]    [Pg.1029]    [Pg.83]    [Pg.151]    [Pg.200]    [Pg.202]    [Pg.9]    [Pg.19]    [Pg.197]    [Pg.1004]    [Pg.1006]    [Pg.1007]    [Pg.95]    [Pg.96]    [Pg.197]    [Pg.98]    [Pg.11]    [Pg.1058]    [Pg.1059]    [Pg.49]    [Pg.58]    [Pg.59]    [Pg.38]    [Pg.324]    [Pg.903]    [Pg.3578]    [Pg.3982]    [Pg.21]    [Pg.343]    [Pg.345]    [Pg.348]   
See also in sourсe #XX -- [ Pg.39 , Pg.219 , Pg.223 ]




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Tetracyclin

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