A. Mushtaq

Synthesis and biodistribution of 99mTc-Vancomycin in a model of bacterial infection

Abstract Vancomycin Hydrochloride is an antibiotic produced by the growth of certain strains of Streptomyces orientalis. As Vancomycin Hydrochloride is poorly absorbed after oral administration; it is given intravenously for therapy of systemic infections. Vancomycin was labeled with technetium-99m pertechnetate using SnCl2·2H2O as reducing agent. The labeling efficiency depends on ligand/reductant ratio, pH, and volume of reaction mixture. Radiochemical purity and stability of 99mTc-Vancomycin was determined by thin layer chromatography. Biodistribution studies of 99mTc-Vancomycin were performed in a model of bacterial infection in Sprague–Dawley rats. A significantly higher accumulation of 99mTc-Vancomycin was seen at sites of S. aureus infected animals. Whereas uptake of 99mTc-Vancomycin in turpentine inflamed rats were quite low.

Concentration of 99mTc-pertechnetate and 188Re-perrhenate

Summary The radioactive concentrations of 99mTc/188Re from their generators are dependent upon the specific activity of 99Mo/188W, which dictates the bed size of the alumina/gel column and the volume of physiological saline needed as eluent. Because of the high content of inactive molybdenum/tungsten in neutron irradiated MoO3/WO3, large columns containing alumina/gel are needed to produce chromatographic 99Mo → 99mTc/188W → 188Re generators. This results in large elution volumes containing relatively high 99Mo/188W contents and low concentrations of 99mTc/188Re. The decrease in radioactive concentration, or specific volume, places a limitation on some of the clinical procedures. We report post elution concentration of 99mTc/188Re using in house prepared silver cation exchange and alumina column. The high bolus volumes (10 − 60 ml saline) can conveniently be concentrated in 1 ml of saline. This approach also works very effectively to yield high specific volume solutions of 99mTc-pertechnetate from a fission 99Mo loaded alumina generator towards the end of its normal working life.

Production of no-carrier-added64Cu and67Cu in a reactor

Fission neutron spectrum averaged cross-sections were measured for the reactions64Zn(n, p)64Cu,67Zn(n, p)67Cu and68Zn(n, α)65Ni by the activation technique, using radiochemical separations and γ-spectroscopy. The preparation of64Cu and67Cu in a nuclear reactor was studied. The64, 67Cu was separated from zinc matrix activity using anion exchange column technique.

Direct labeling of isoniazid with technetium-99m for diagnosis of tuberculosis

Summary Isonicotinic acid hydrazide (isoniazid) is one of the most effective agents in tuberculosis therapy. Hence it was chosen as ligand for 99mTc labeling and imaging in the developed animal model with a gamma camera. Direct labeling of isoniazid with technetium-99m was studied. Factors affecting the radiolabeling efficiency such as amount of reducing agent, pH and time of the reaction were studied. Biodistribution of the labeled compound was performed in Sprague–Dawley rats. The localization kinetics of the radiolabeled complex was also studied in the developed animal model by injecting 100–125 MBq 99mTc-isoniazid intravenously in the ear of rabbit and the images were taken with a gamma camera. Optimum conditions gave > 98% labeling efficiency of 99mTc-isoniazid. Biodistribution studies in rats revealed that the maximum uptake was in kidneys (15%, 8% and 2.5% at 0.5, 4 and 24 hours, respectively), indicating renal excretion of the 99mTc-isoniazid. High accumulation was obtained in liver (10%, 11% and 4% at 0.5, 4 and 24 hours, respectively) and significant radioactivity was also seen in the intestines (8%, 6% and 1% at 0.5, 4 and 24 hours, respectively), indicating hepatobiliary excretion of the complex. Less than 2% uptake in stomach until 24 hours confirmed good in vivo stability of the complex. 99mTc-isoniazid initially accumulated in infective lesions of S. aureus in rabbits due to hyper-vascularity, but because of its non specificity for S. aureus the residency of 99mTc-isoniazid was low and it showed rapid wash out from the lesion, whereas residency of tubercular lesion was high and it remained in the tubercular lesion in the delayed images also. The results suggest that 99mTc-isoniazid is a specific agent for localization of tubercular lesions.

Hydrated titanium dioxide as an adsorbent for99Mo−99mTc generator

The adsorption behaviour of99Mo in the form of molybdate and of99mTc in the form of pertechnetate on hydrated titanium dioxide was investigated at different molarities of hydrochloric acid. The adsorption capacity of molybdate on hydrated TiO2 is higher than on Al2O3. A99mTc-generator is suggested. This generator is based on the adsorption of (99Mo) molybdate on hydrated TiO2, at acidities of 0.05–0.1M. HCl.99mTc is eluted with 0.9% NaCl. Radionuclidic, radiochemical and chemical purities of the eluates were checked. This generator seems to have a great potential as compared to the traditional alumina generators.

Separation of 199Au(NCA) from Neutron Irradiated Platinum on Polythene

For irradiation of small tumour mass, β emissions with mean range of less than 200 μπι are particularly suitable [1], For radioimmunotherapy, 1 9 Au is a suitable radionuclide due to its 3.14 d half-life, 0.08 MeV average β energy and 158 keV photon energy for γ imaging. Labelling of antibodies with 1 9 Au has already been reported [2, 3]. Several nuclear reactions have been exploited for production of Au, such as reactions on Hg and charged particle reactions with platinum [4,5] but high specific activity Au is mainly produced via Pt(n,y)Pt Au. Separation of 1 9 Au from Pt has been carried out by solvent extraction and ionexchange [6 — 11], Present studies have been aimed to develop a simple and rapid adsorption method for preparation of high specific activity 1 9 Au from Pt. Polythene powder has been used as a sorbent and high nuclidic purity Au has been obtained in form of Au(III).

Separation of 111Ag from Neutron Irradiated Natural Palladium

Radioimmunotherapy (RAIT) is dependent on several contributing factors including the radiosensitivity of the target tumor, the characteristics of the chosen antibody and the nature of the radionuclide employed. m A g has good beta emission characteristics, an appropriate half life of 7.5 d and low y-ray component [1], I f 1 1 1 Ag can be produced in large quantities and linked to the carrier antibody, it may replace I in many cases [2], 111 Ag is produced as follows:

Separation of radioindium (N.C.A.) from neutron irradiated tin and cadmium on hydrated antimony pentoxide

Hydrated antimony pentoxide (HAP) as an absorbent for column operation has been prepared by hydrolysis of SbCl5 with deionized water. Sorption behavior of Sn, Cd, Sb and In was studied on HAP in HCl medium. Radiochemical separation of no-carrier added113mIn from113Sn/125Sb and115mIn from115Cd wa achieved over a HAPO column. The separated products were of high radionuclidic purity.

Technetium(99m)-tin colloid: A simple method for the preparation and evaluation

Effect of various amounts of reagents on the quality of99mTc−Sn-colloid has been studied, and a simple and reproducible method for its preparation particularly suitable for hospital pharmacy has been developed. PVP has been used as a stabilizing agent. A quick method of its bio-distribution has also been described.

A Freeze Dried Kit for 99mTc(V) Dimercaptosuccinic Acid

Abstract99mTc pentavalent dimercaptosuccinic acid [99mTc(V) DMSA], a useful agent for imaging thyroid medullary carcinoma and other tumors can be reliably prepared by addition of Na99mTcO4 to a freeze-dried mixture of DMSA and Sn (2:1 molar ratio). The radiochemical purity, stability and animal bio-distribution behaviour is similar to that of the agent made by addition of NaHCO3 to DMSA (III) renal imaging freeze-dried kit.