WILBERT

Wildauer Bücher+E-Medien Recherche-Tool

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Ponds and streams in Braxton, Kanawha, Mason, Jackson, and Hampshire Counties, West Virginia, were sampled to determine the accumulation, persistence, and movement of picloram residues in surface waters and bottom sediments. The highest residue levels of 437 gmg/L in water and 657 gmg/kg dry weight basis (243 gmg/kg wet weight basis) in bottom sediments were detected within one to three weeks after application of picloram (Tordon 10K) pellets at the rate of 44.8 product kg/ha. Residue levels in water and sediments decreased with distance from application sites and time since application.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 339 (1989), S. 718-721 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The binding sites for myc-PRF and myc-CFl, as identified by orthophenanthroline/copper (OP/Cu) chemical nuclease footprinting2'3 and methylation interference2, are shown in Fig. 1 (also Fig. 3a). To test myc-PRF function, we used oligonucleo-tide-directed mutagenesis to delete 14 base pairs (bp) of ...
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Pharmaceutical research 16 (1999), S. 272-280 
    ISSN: 1573-904X
    Keywords: biopharmaceutic classification system ; peak concentration ; permeability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. To theoretically investigate the impact of gastric emptying half-time, intestinal transit time and the time for 85% in vivo dissolution on the peak concentration and area-under-the curve of model drugs. Methods. Simulations were performed using mathematical models of gastrointestinal physiology and pharmacokinetics of model drugs with different gastrointestinal permeability. They were used to investigate the effect of different permutations of gastric emptying times, intestinal transit times, dissolution rates and effective permeabilities on the maximum plasma drug concentration and the area-under-the-curve of immediate release tablets relative to an oral solution (i.e., Cmaxtablet/ Cmaxsolution and AUCtablet/AUCsolution). Results. The higher the permeability of the drug, the more sensitive the Cmax ratio is to dissolution rate and gastric emptying rate. As the intestinal transit time becomes more rapid, the sensitivity to T85% dissolution time and gastric emptying half-time increases. There is less dependence for the AUC ratio on the gastric emptying time and dissolution rate. Conclusions. Under the assumptions of the models, the criterion of 85% dissolution in 15 minutes (T85%) for classifying a rapidly dissolving drug product is relatively conservative since the Cmax ratio exceeded 0.8 for a T85% dissolution time of one hour and a gastric emptying half-time faster than 0.2 hour over a wide range of permeabilities.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Pharmaceutical research 8 (1991), S. 254-258 
    ISSN: 1573-904X
    Keywords: mean residence time ; volume of distribution at steady state ; intravenous infusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The following equations are derived for amount of drug in the body (x bss), volume of distribution (v ss), and mean residence time in the body (t b) at steady state during a continuous constant rate infusion of drug. x bss = R/c ss∫0 ∞[c ss - c(t)]dt = R∫0 ∞[1 - c(t)/c ss]dt v ss = x bss/c ss = R/c 2 ss∫0 ∞[c ss - c(t)]dt = R/c ss∫0 ∞[1 - c(t)/c ss]dt t b = x bss/R = v ss/CL = 1/c ss∫0 ∞[c ss - c(t)]dt = ∫0 ∞[1 - c(t)/c ss]dt where c(t) ≡ drug concentration in the systemic circulation at time t following the start of a constant-rate infusion, c ss ≡ steady-state systemic drug concentration, and R ≡ infusion rate. The equations are based on the assumption that the rate of drug elimination is proportional to the systemic drug concentration. The equations provide the basis for simple methods that are presented for estimating x bss, v ss, and t b directly from experimental data. More general relationships are also derived for cases where the continuous infusion is preceded by other modes of administration, e.g., a bolus loading dose followed by a constant-rate infusion.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 293 (1981), S. 462-464 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Cupules terminate a bifurcating branch system. In the more extensive specimens the bottom forks are relatively equal while more distal forks are less so and occur at progressively closer intervals. The cupules (Figs 2a-c, 3), l-cm long and apically flared to 1-cm wide, also consist of a ...
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1573-904X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    ISSN: 1573-8744
    Keywords: methylprednisolone ; bioavailability ; pharmacokinetics ; oral and parenteral administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This study was conducted to evaluate the influence of route of administration upon the bioavailability and pharmacokinetics of methylprednisolone sodium succinate. Fourteen healthy adult male volunteers received 40 mg doses of methylprednisolone as the following treatments after an overnight fast in a 4-way crossover design: (a) as a 1 ml i.v. bolus;(b) as a 1 ml i.m. injection;(c) administered as an oral solution;and (d) as 5×8 mg oral tablets. Both the ester and free methylprednisolone were determined in plasma and urine. Study results indicate that the ester is rapidly and extensively converted to free methylprednisolone after all routes. The extent of methylprednisolone absorption was equivalent after i.v. and i.m. administration. Both orally administered treatments resulted in a lower extent of absorption attributed to a first-pass effect. Although a slightly lower extent of absorption was demonstrated following the oral administration of the methylprednisolone sodium succinate solution relative to the methylprednisolone oral tablets, this average difference of 9% would probably be of minimal therapeutic importance.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    ISSN: 1573-8744
    Keywords: linear systems analysis ; deconvolution ; induced drug removal ; activated charcoal ; phenobarbital ; hemodialysis ; peritoneal dialysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The theory of linear systems analysis is applied to the evaluation of induced drug removal processes. The rate and extent of removal are determined by deconvolution for the case of phenobarbital removal from the systemic circulation by orally administered activated charcoal. The proposed method is model independent in the sense that no specific models of intrinsic or induced pharmacokinetic processes are required, and it is readily adapted to the analysis of most types of induced removal processes (hemodialysis, peritoneal dialysis, etc.). Application of the approach indicates that phenobarbital was removed from the systemic circulation to an extent of 25–53% following multiple oral doses of activated charcoal in healthy human subjects.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    ISSN: 1573-8744
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    ISSN: 1573-8744
    Keywords: deconvolution ; deconvolution algorithm ; deconvolution computer program ; ibuprofen dosage forms ; ibuprofenin vivo release ; meanin vivo dissolution timeMDT ; gastrointestinal bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new deconvolution algorithm (DCON) suitable for pharmacokinetic applications is presented. It requires that both the impulse and input responses, typically systemic drug levels, be well described by polyexponential equations. DCON has a wider range of applications than an earlier method (DECONV) from which it is derived. A FORTRAN program is provided, making implementation of the technique a simple matter. DCON is demonstrated to evaluate the “GI bioavailability,” defined as the rate and the extent of gastrointestinal drug release, of various ibuprofen dosage forms. The GI drug release kinetics exemplifies a pharmacokinetic system which cannot be evaluated using the previous deconvolution algorithm (DECONV) because of an initial zero drug level response. This limitation is not found in DCON. It is also demonstrated how the mean in vivo dissolution time MDT can be evaluated by deconvolution.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...