Moving Toward Continuous Organ Distribution

Phenolphthalexon, a compound with iminodiacetic acid as a functional group, has been labelled with 113mIn to high chemical purity and its usefulness in studies of biliary excretion patency has been studied. Organ distribution of 113mIn-phenolphthalexon in mice was characterized by high liver uptake (50.8% of the administered dose after 5 min) and rapid clearance through the gall bladder. An animal model for studying obstruction of biliary excretion has been developed. Data on the kinetics of the radiopharmaceutical were obtained by collecting in-vivo data through an on-line computer.

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Instant 99mTc-Labelled Glucoheptonate Kit for Kidney Imaging

Nuklearmedizin ◽

10.1055/s-0038-1624139 ◽

1983 ◽

Vol 22 (05) ◽

pp. 246-250 ◽

Cited By ~ 2

Author(s):

M. Al-Hilli ◽

H. M. A. Karim ◽

M. H. S. Al-Hissoni ◽

M. N. Jassim ◽

N. H. Agha

Keyword(s):

Sodium Hydroxide Solution ◽

Normal Subjects ◽

Organ Distribution ◽

Stable Complex ◽

Scintillation Camera ◽

Ph Adjustment ◽

The Mean ◽

The Stability ◽

Kidney Imaging ◽

Mean Concentration

Gelchromatography column scanning has been used to study the fractions of reduced hydrolyzed 99mTc, 99mTc-pertechnetate and 99mTc-chelate in a 99mTc-glucoheptonate (GH) preparation. A stable high labelling yield of 99mTc-GH complex in the radiopharmaceutical has been obtained with a concentration of 40-50 mg of glucoheptonic acid-calcium salt and not less than 0.45 mg of SnCl2 2 H2O at an optimal pH between 6.5 and 7.0. The stability of the complex has been found significantly affected when sodium hydroxide solution was used for the pH adjustment. However, an alternative procedure for final pH adjustment of the preparation has been investigated providing a stable complex for the usual period of time prior to the injection. The organ distribution and the blood clearance data of 99mTc-GH in rabbits were relatively similar to those reported earlier. The mean concentration of the radiopharmaceutical in both kidneys has been studied in normal subjects for one hour with a scintillation camera and the results were satisfactory.

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Vorklinische Untersuchung zur Organverteilung und Strahlenbelastung von Radiojod-Jodlisurid

Nuklearmedizin ◽

10.1055/s-0038-1629565 ◽

1991 ◽

Vol 30 (04) ◽

pp. 137-140

Author(s):

H. Flade ◽

B. Johannsen ◽

V. Pink ◽

U. Herold ◽

R. Harhammer ◽

...

Keyword(s):

Radiation Dose ◽

The Body ◽

Organ Distribution ◽

Clinical Use ◽

Isolated Organs

The distribution in rats of 125l-iodolisuride was studied. Three rats each were sacrificed at fixed intervals between 5 min and 24 h p. i., and the radioactivity was measured in isolated organs and parts of the body. The organ distribution and biexponential blood disappearance were similar to values for unlabeled lisuride. The radiation dose was estimated for man assuming a 123l label. The resulting doses were comparable to those from other radiopharmaceuticals in clinical use.

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Turnover of Human Extrinsic (Tissue-Type) Plasminogen Activator in Rabbits

Thrombosis and Haemostasis ◽

10.1055/s-0038-1653442 ◽

1981 ◽

Vol 46 (03) ◽

pp. 658-661 ◽

Cited By ~ 112

Author(s):

C Korninger ◽

J M Stassen ◽

D Collen

Keyword(s):

Plasminogen Activator ◽

Intravenous Injection ◽

Active Site ◽

Half Life ◽

Degradation Products ◽

Gel Filtration ◽

Tissue Type ◽

Organ Distribution ◽

Small Rise

SummaryThe turnover of highly purified human extrinsic plasminogen activator (EPA) (one- and two-chain form) was studied in rabbits. Following intravenous injection, EPA-activity declined rapidly. The disappearance rate of EPA from the plasma could adequately be described by a single exponential term with a t ½ of approximately 2 min for both the one-chain and two-chain forms of EPA.The clearance and organ distribution of EPA was studied by using 125I-labeled preparations. Following intravenous injection of 125I-1abeled EPA the radioactivity disappeared rapidly from the plasma also with a t ½ of approximately 2 min down to a level of 15 to 20 percent, followed by a small rise of blood radioactivity. Gel filtration of serial samples revealed that the secondary increase of the radioactivity was due to the reappearance of radioactive breakdown products in the blood. Measurement of the organ distribution of 125I at different time intervals revealed that EPA was rapidly accumulated in the liver, followed by a release of degradation products in the blood.Experimental hepatectomy markedly prolonged the half-life of EPA in the blood. Blocking the active site histidine of EPA had no effect on the half-life of EPA in blood nor on the gel filtration patterns of 125I in serial plasma samples.It is concluded that human EPA is rapidly removed from the blood of rabbits by clearance and degradation in the liver. Recognition by the liver does not require a functional active site in the enzyme. Neutralization in plasma by protease inhibitors does not represent a significant pathway of EPA inactivation in vivo.

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195. Kerosene Cleaning Disturbs the Barrier Function of the Skin and Alters the Organ Distribution of Bap Applied Topically In Mice

10.3320/1.2765714 ◽

2001 ◽

Author(s):

G. Talaska ◽

C. LaDow ◽

B. Schumann ◽

N. Luce ◽

D. Warshawsky ◽

...

Keyword(s):

Barrier Function ◽

Organ Distribution

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5-Fluorouracil Loaded Orally Administered WGA-decorated Poly(lactic-co-glycolic acid) Nanoparticles for Treatment of Colorectal Cancer: In Vivo Evaluation

Current Nanomedicine ◽

10.2174/2468187310999201123195233 ◽

2020 ◽

Vol 10 ◽

Author(s):

Aditya Nath Pandey ◽

Kuldeep Rajpoot ◽

Sunil K. Jain

Keyword(s):

Colorectal Cancer ◽

Colon Cancer ◽

Oral Delivery ◽

Wheat Germ ◽

Glycolic Acid ◽

Organ Distribution ◽

In Vivo Evaluation ◽

Distribution Study ◽

Prolonged Retention

Background:: Several studies have suggested potential aptitude of polylactic-co-glycolic acid (PLGA)-derived nanoparticles (NPs) to improve the antitumor efficacy of anticancer drugs against colon cancer. Further, conjugation of lectins over the surface of the NPs may ameliorate interaction and thus enhance attachment of NPs with receptors. Objective:: The main goal of the study was to prepare and evaluate targeting potential (in vivo) of the optimized NPs against colorectal cancer. Methods:: The 5-fluorouracil (5-FU) loaded and wheat germ agglutinin (WGA)-conjugated PLGA-NPs (WFUNPs) were prepared and then they were evaluated in vivo for targeting aptitude of formulation using gamma scintigraphy after oral delivery. The WGA-conjugated and non-conjugated optimized NPs were compared for any significant results. Further, optimized formulations were also assessed for different parameters such as radiolabeling efficiency, sodium pertechnetate uptake, stability of NPs, and organ distribution study. Results:: Findings suggested prolonged retention of 99mTc-tagged WFUNPs in the colonic region after 24 h study. Eventually, the outcome from conjugated formulation revealed enhanced bioavailability of the drug in blood plasma for up to 24 h. Conclusion:: In conclusion, WGA-conjugation to NPs could improve the performance of the PLGA-NPs in the treatment of colorectal cancer.

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Simultaneous Visualization of 161Tb- and 177Lu-Labeled Somatostatin Analogues Using Dual-Isotope SPECT Imaging

Pharmaceutics ◽

10.3390/pharmaceutics13040536 ◽

2021 ◽

Vol 13 (4) ◽

pp. 536

Author(s):

Francesca Borgna ◽

Patrick Barritt ◽

Pascal V. Grundler ◽

Zeynep Talip ◽

Susan Cohrs ◽

...

Keyword(s):

Pharmacokinetic Profile ◽

Somatostatin Analogues ◽

Distribution Coefficients ◽

Spect Imaging ◽

Cell Uptake ◽

Organ Distribution ◽

Dual Isotope ◽

Biodistribution Studies ◽

Simultaneous Visualization

The decay of terbium-161 results in the emission of β¯-particles as well as conversion and Auger electrons, which makes terbium-161 interesting for therapeutic purposes. The aim of this study was to use dual-isotope SPECT imaging in order to demonstrate visually that terbium-161 and lutetium-177 are interchangeable without compromising the pharmacokinetic profile of the radiopharmaceutical. The 161Tb- and 177Lu-labeled somatostatin (SST) analogues DOTATOC (agonist) and DOTA-LM3 (antagonist) were tested in vitro to demonstrate equal properties regarding distribution coefficients and cell uptake into SST receptor-positive AR42J tumor cells. The radiopeptides were further investigated in AR42J tumor-bearing nude mice using the method of dual-isotope (terbium-161/lutetium-177) SPECT/CT imaging to enable the visualization of their distribution profiles in the same animal. Equal pharmacokinetic profiles were demonstrated for either of the two peptides, irrespective of whether it was labeled with terbium-161 or lutetium-177. Moreover, the visualization of the sub-organ distribution confirmed similar behavior of 161Tb- and 177Lu-labeled SST analogues. The data were verified in quantitative biodistribution studies using either type of peptide labeled with terbium-161 or lutetium-177. While the radionuclide did not have an impact on the organ distribution, this study confirmed previous data of a considerably higher tumor uptake of radiolabeled DOTA-LM3 as compared to the radiolabeled DOTATOC.

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