Removal of Cephalosporins by Continuous Arteriovenous Ultrafiltration (CAVU) and Hemofiltration (CAVH)

1989 ◽  
Vol 12 (6) ◽  
pp. 379-383 ◽  
Author(s):  
A.H. Lau ◽  
K. Pyle ◽  
N.O. Kronfol ◽  
C.R. Libertin
Keyword(s):  
Protein Binding ◽  
In Vitro Model ◽  
Plasma Drug ◽  
Flow Rates ◽  
Drug Concentrations ◽  
Vitro Model ◽  
Arterial Plasma ◽  
Kinetics Of ◽  
Venous Plasma

Cephalosporins are used with increasing frequency for sepsis treatment in patients receiving CAVU and CAVH. The different cephalosporins share the same basic molecular structure, yet they exhibit varied extent of plasma protein binding. Different amounts of the antibiotics may be removed by the ultrafiltration procedure because of these variations of physicochemical properties. We evaluated the sieving of eight new cephalosporins across the hemofilter membrane using an in vitro model. Bovine blood was perfused through polysulfone membranes at blood and ultrafiltrate flow rates of 100 and 20 ml/min respectively. Arterial plasma, venous plasma and ultrafiltrate drug concentrations were used to determine sieving coefficients. The sieving coefficients correlated well with the ultrafiltrate-arterial plasma drug concentration ratio (r= 0.679 - 0.972) but poorly with the extent of protein binding. Factors other than protein binding may therefore affect the drug sieving. Based on the findings, it was predicted that 0.2 - 21.9% of the daily cephalosporin dose may be removed by the CAVU and CAVH treatment. The need to alter drug dosages depends on the techniques of the ultrafiltration and hemofiltration procedure, the kinetics of the cephalosporins in patients, the sensitivity of the pathogen and the nature of the infection.

scholarly journals Effect of protein binding on simulated intravascular and extravascular kinetics of cefotaxime in an in vitro model.

1984 ◽  
Vol 25 (1) ◽  
pp. 58-61 ◽  
Author(s):  
L R Peterson ◽  
L L Van Etta ◽  
C E Fasching ◽  
D N Gerding
Keyword(s):  
Protein Binding ◽  
In Vitro Model ◽  
Vitro Model ◽  
Kinetics Of

Clearance of Levofloxacin by an in Vitro Model of Continuous Venovenous Hemodialysis (CVVHD)

2007 ◽  
Vol 30 (10) ◽  
pp. 889-895 ◽  
Author(s):  
S. Siewert ◽  
B. Drewelow ◽  
S.C. Mueller
Keyword(s):  
In Vitro Model ◽  
Urea Clearance ◽  
Flow Rates ◽  
Dialysate Flow ◽  
Dialysate Flow Rate ◽  
Continuous Venovenous Hemodialysis ◽  
Vitro Model ◽  
Positive Correlations

Information about the elimination and the adequate dosing of levofloxacin during renal replacement therapy is scarce. The aim of this study was to characterize in vitro the elimination of levofloxacin during continuous venovenous hemodialysis (CVVHD) and to investigate whether the CVVHD clearances of creatinine and urea are correlated with the levofloxacin clearance in order to facilitate dosage adjustments. An in vitro model of CVVHD was established using five dialyzer membranes at varying dialysate flow rates applied in the clinical setting (8, 16, 25, 33 and 41 ml/min). Plasma and dialysate samples were drawn for determination of levofloxacin, creatinine and urea concentrations to evaluate clearances by CVVHD. During CVVHD, the clearance of levofloxacin varied between 9.02 and 33.30 ml/min, depending on the chosen setup. Positive correlations (p<0.001) were received for: dialysate flow rate (QD) and creatinine/urea clearances (R>0.93); QD and levofloxacin clearance (R 0.59–0.71); levofloxacin and creatinine clearance (R 0.69–0.75); and levofloxacin and urea clearance (R 0.56–0.75) as well. When dosing critically ill patients, therefore, extracorporeal as well as total clearance of levofloxacin should be considered.

scholarly journals Investigation of Solvolysis Kinetics of New Synthesized Fluocinolone Acetonide C-21 Esters—An In Vitro Model for Prodrug Activation

Molecules ◽  
2011 ◽  
Vol 16 (3) ◽  
pp. 2658-2671 ◽  
Author(s):  
Bojan D. Markovic ◽  
Vladimir D. Dobricic ◽  
Sote M. Vladimirov ◽  
Olivera A. Cudina ◽  
Vladimir M. Savic ◽  
...  
Keyword(s):  
In Vitro Model ◽  
Fluocinolone Acetonide ◽  
Prodrug Activation ◽  
Vitro Model ◽  
Kinetics Of

scholarly journals Control of the Transdermal Delivery Process of Active Substances of the Phytocomplex during Phonophoresis in Model Experiments

2019 ◽  
Vol 7 (13) ◽  
pp. 2079-2083
Author(s):  
Liudmila Ivanovna Babaskina ◽  
Tatiana Mikhailovna Litvinova ◽  
Dmitrii Vladimirovich Babaskin ◽  
Olga Valerevna Krylova
Keyword(s):  
Dimethyl Sulfoxide ◽  
Transdermal Delivery ◽  
In Vitro Model ◽  
The Body ◽  
Model Experiments ◽  
Vitro Model ◽  
Franz Diffusion Cells ◽  
Kinetics Of ◽  
Active Substances

BACKGROUND: The scientific substantiation for the selection of therapeutically significant dosage of phytocomplex in the dosage form for phonophoresis, control over the delivery of active substances into the body, and what affects this process require the study of the kinetics of phytocomplex flavonoids delivery during phonophoresis. AIM: The aim was to study the possibilities of controlling the process of transdermal delivery of phytocomplex active substances (flavonoids) during phonophoresis in vitro model experiments. METHODS: Working compositions with different concentrations of phytocomplex for phonophoresis were used. The content of flavonoids in the compositions was determined using the spectrophotometric method and was calculated equivalent to quercetin, the flavonoid prevailing in the phytocomplex. The study of the kinetics of flavonoids delivery from working compositions was carried out using Franz diffusion cells and Carbosyl-P membranes. The authors determined the main parameters of the process and established the dependence of the delivery rate of flavonoids on their initial concentration in the working composition. The authors studied the effect of dimethyl sulfoxide and the base-forming substances of the working composition on the kinetics of phytocomplex flavonoid delivery during phonophoresis. RESULTS: The authors recorded an increase in the rate of delivery of the active substances from working compositions containing dimethyl sulfoxide into the model medium by almost 1.5-2 times during the first ten minutes of the experiment (approximate duration of the phonophoresis procedure). The authors proposed technological techniques for improvement of the phonophoresis method for the phytocomplex. The possibilities of control over the process of transdermal delivery of the phytocomplex active ingredients during phonophoresis in vitro model experiments were shown. CONCLUSION: The obtained results provide information for further pharmacological studies of the nature and mechanism of the effect of phytocomplex flavonoids during phonophoresis in the rehabilitation of patients with osteoarthrosis.

The effect of air exposure on leucocyte and cytokine activation in an in-vitro model of cardiotomy suction

Perfusion ◽  
2018 ◽  
Vol 33 (7) ◽  
pp. 538-545 ◽  
Author(s):  
Cory J. Toomasian ◽  
Salvatore R. Aiello ◽  
Benjamin L. Drumright ◽  
Terry C. Major ◽  
Robert H. Bartlett ◽  
...  
Keyword(s):  
In Vitro Model ◽  
Air Flow ◽  
Air Exposure ◽  
Flow Rates ◽  
Cytokine Activation ◽  
Cardiotomy Suction ◽  
Cytokine Levels ◽  
Vitro Model ◽  
Heparin Exposure

Introduction: Cardiopulmonary bypass (CPB) is known to cause a systemic inflammatory and immune response. Objective: An in-vitro model of cardiotomy suction was designed to quantify the effects of incrementally increased air-blood exposure on leucocyte marker CD11b and cytokine activation in two common anticoagulants, heparin and citrate. Methods: Fresh human blood was exposed to increasing amounts of air flow for ten minutes. Leucocyte and cytokine levels were measured prior to and after ten minutes of air flow. Cytokine levels were also measured after air exposure when incubated for 24 hours at 37oC. Results: Leucocyte activation, measured by CD11b, was elevated between baseline and air flow rates up to 50 mL/min. After 10 minutes of air exposure, no measured cytokine levels were elevated. After 24 hours of incubation, cytokine levels of TNFα, IL-10, IL-6, and IL-8 were elevated. However, only IL-8 was significantly elevated in citrated blood, but not in heparinized blood, when compared to baseline samples that were also incubated for 24 hours. Conclusion: This study investigates CD11b levels in response to an air stimulus in blood that was anticoagulated with citrate or heparin. Exposure to an air stimulus activates leucocytes. Activation of CD11b was less when using heparin as an anticoagulant compared to citrate. Cytokine activation occurs with air stimulation, but levels do not immediately rise, indicating that time is required to generate free cytokines.

Methods for detecting local intestinal ischemic anaerobic metabolic acidosis by P CO 2

1996 ◽  
Vol 81 (4) ◽  
pp. 1834-1842 ◽  
Author(s):  
Ranna A. Rozenfeld ◽  
Michael K. Dishart ◽  
Tor Inge Tønnessen ◽  
Robert Schlichtig
Keyword(s):  
Blood Flow ◽  
Metabolic Acidosis ◽  
Anaerobic Threshold ◽  
In Vitro Model ◽  
Venous Blood ◽  
Flow Reduction ◽  
Portal Venous Blood ◽  
Vitro Model ◽  
Arterial Plasma

Rozenfeld, Ranna A., Michael K. Dishart, Tor Inge Tønnessen, and Robert Schlichtig. Methods for detecting local intestinal ischemic anaerobic metabolic acidosis by[Formula: see text]. J. Appl. Physiol. 81(4): 1834–1842, 1996.—Gut ischemia is often assessed by computing an imaginary tissue interstitial pH from arterial plasma [Formula: see text] and the[Formula: see text] in a saline-filled balloon tonometer after equilibration with tissue[Formula: see text](P[Formula: see text]). P[Formula: see text] may alternatively be assumed equal to venous[Formula: see text]([Formula: see text]) in that region of gut. The idea is that as blood flow decreases, gut P[Formula: see text] and[Formula: see text] will increase to the maximum aerobic value, i.e., maximum respiratory[Formula: see text]([Formula: see text]). Above a “critical” anaerobic threshold, lactate (La−) generation, by titration of tissue [Formula: see text], should raise P[Formula: see text]above[Formula: see text]. During progressive selective whole intestinal flow reduction in six pentobarbital-anesthetized pigs, we used[Formula: see text] electrodes to test the hypotheses that critical P[Formula: see text]is achieved earlier in mucosa than in serosa and that[Formula: see text], computed using an in vitro model, predicts critical P[Formula: see text]. We defined critical P[Formula: see text] as the inflection of P[Formula: see text]-[Formula: see text]vs. O2 delivery (Q˙o 2) plots. CriticalQ˙o 2for O2 uptake was 12.55 ± 2 ml ⋅ kg−1 ⋅ min−1. Critical P[Formula: see text] for mucosa and serosa was achieved at similar whole intestineQ˙o 2(13.90 ± 5 and 13.36 ± 5 ml ⋅ kg−1 ⋅ min−1, P = NS). Critical P[Formula: see text] (129 ± 24 and 96 ± 21 Torr) exceeded[Formula: see text](62 ± 3 Torr). During ischemia, La− excretion into portal venous blood was matched by K+excretion, causing [Formula: see text] to increase only slightly, despite P[Formula: see text] rising to 380 ± 46 (mucosa) and 280 ± 38 (serosa) Torr. These results suggest that mucosa and serosa become dysoxic simultaneously, that ischemic dysoxic gut is essentially unperfused, and that in vitro predicted[Formula: see text]underestimates critical P[Formula: see text].

scholarly journals Liposomal Thyroxine: A Noninvasive Model for Transplacental Fetal Therapy*

1997 ◽  
Vol 82 (10) ◽  
pp. 3271-3277
Author(s):  
Rekha Bajoria ◽  
Nicholas M. Fisk ◽  
Soli F. Contractor
Keyword(s):  
In Vitro Model ◽  
Human Term Placenta ◽  
Transplacental Transfer ◽  
Term Placenta ◽  
Marker Substances ◽  
Anionic Liposomes ◽  
Vitro Model ◽  
Kinetics Of

Abstract Drugs that cross the placenta sparingly are currently given directly to the fetus by invasive procedures. We investigated whether anionic small unilamellar (SUV) liposomes of different lipid compositions enhanced the transfer and uptake of T4 in an in vitro model of perfused human term placenta. T4-encapsulated anionic liposomes were prepared using lecithin (F-SUV) or distearoyl phosphatidylcholine (S-SUV) with cholesterol and dicetylcholine. The size distribution, encapsulation efficiency, and stability were determined in blood-based media. The transfer kinetics of free and liposomally encapsulated T4 were studied in a dually perfused isolated lobule of human term placenta, with creatinine and liposomal carboxyfluorescein as marker substances. Concentrations of T4 and rT3 were measured by RIA. T4 crossed the placenta sparingly (1.9 ± 0.5%) because it was metabolized to rT3 (9.2 ± 1.3%). Transplacental transfer of T4 was significantly increased by F-SUV (15.8 ± 2.1%; P &lt; 0.001) and S-SUV liposomes (7.1 ± 1.2%; P &lt; 0.001), with a concomitant decrease in fetal rT3 levels (P &lt; 0.001). Placental uptake of F-SUV (13.5 ± 2.0%; P &lt; 0.001) was greater than that of S-SUV liposomes (6.7 ± 0.8%; P &lt; 0.001). Our data suggest that anionic liposomes increase transplacental transfer of T4. If confirmed in vivo, liposomes may provide an alternative noninvasive method of drug delivery to the fetus.

A simple in vitro model to study the release kinetics of liposome encapsulated material

1998 ◽  
Vol 56 (1-3) ◽  
pp. 41-51 ◽  
Author(s):  
Regine Peschka ◽  
Cathi Dennehy ◽  
Francis C Szoka Jr
Keyword(s):  
In Vitro Model ◽  
Release Kinetics ◽  
Vitro Model ◽  
Kinetics Of
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