Mechanochemically synthesized mesoporous alumina: An advanced sorbent for post-processing concentration of 131I for cancer therapy.

High radioactive concentration of 131I in the form of 131I[NaI] solution is essential for preparation of large-dose therapeutic capsules used in the management of thyroid cancer. In this communication, we report the synthesis of mesoporous alumina sorbent (surface area = 292 ±â€¯28 m2/g, mean pore diameter = 6.8 ±â€¯0.7 nm) by a novel solid state mechanochemical approach and its utilization in post-processing concentration of 131I. The overall yield of 131I after the concentration procedure was >90% and 131I[NaI] solution could be obtained with appreciably high (1.7 TBq/mL) radioactive concentration, suitable for use in nuclear medicine. The promising results obtained in this study would stimulate greater utilization of this new class of sorbents in sample preparations by solid phase extraction procedures for societal benefits.

Study of adsorption characteristics of Au(III) onto coal particles and their application as radiotracer in a coal gasifier.

This paper describes a systematic study carried out to investigate adsorption characteristics of 198Au onto the surface of coal particles using a radiotracer technique. The main objective of the study was to optimize labeling conditions and utilize the labeled coal particles as a radiotracer for tracing coal particles in fluidized bed coal gasifiers. The effect of various experimental factors such as pH, amount of adsorbent, initial gold concentration, temperature and contact time between adsorbate and adsorbent were studied to obtain optimum conditions for maximum adsorption of 198Au on coal particles from an aqueous solution. Analysis of the data showed that the Langmuir model was found most suitable to describe the adsorption phenomena. The thermodynamic analysis showed that the adsorption process is feasible, spontaneous and endothermic in nature. The results of the kinetics suggested that the adsorption presumably follows second order kinetics and chemisorption in nature. Based on the optimized conditions, the amount of coal particles and activity to be used for tracing the coal phase in pilot-scale gasifiers was estimated. Accordingly, the radiotracer was prepared and successfully used for measurement of residence time distribution (RTD) in a pilot-scale coal gasifier.

Development of Semiautomated Module for Preparation of 131I Labeled Lipiodol for Liver Cancer Therapy.

Intra-arterial injection of 131I Lipiodol is an effective treatment option for primary hepatocellular carcinoma as it delivers high radiation dose to liver tumor tissue with minimal accumulation in adjacent normal tissue. The present article demonstrates design, fabrication, and utilization of a semiautomated radiosynthesis module for preparation of 131I labeled Lipiodol. The radiolabeling method was standardized for preparation of patient dose of 131I labeled Lipiodol radiochemical yield (RCY); radiochemical purity (RCP) and pharmaceutical purity of the product were determined using optimized procedures. Sterile and apyrogenic 131I labeled Lipiodol in >60% RCY could be prepared with >95% RCP. Preclinical evaluation in animals indicated retention of more than 90% of activity at 24 hours postportal vein injection. This is the first report demonstrating potential application of simple user friendly and safe semiautomated system for routine production of 131I labeled Lipiodol, which is adaptable at centralized hospital radiopharmacies. The described prototype module can be modified as per demand for preparation of other therapeutic radiopharmaceuticals.

Preparation and preclinical evaluation of 131 I-trastuzumab for breast cancer.

Trastuzumab that targets the human epidermal growth factor receptor type 2 (HER2) is known to benefit patients with HER2+ metastatic breast cancer. The objective was to explore the potential of 131 I-trastuzumab for treatment of breast cancers. Radioiodination of trastuzumab was carried out by chloramine-T method, purified by using PD-10 column, and characterized by size exclusion high-performance liquid chromatography on a gel column. In vitro studies were carried out in HER2+ cells to determine the specificity of the radioimmunoconjugate. Uptake and retention of 131 I-trastuzumab were determined by biodistribution studies in tumor-bearing non-obese diabetic/severe combined immunodeficiency and normal severe combined immunodeficiency mice. The radiochemical purity (RCP) of 131 I-trastuzumab was 98 ± 0.4% with retention time of 17 minutes by high-performance liquid chromatography. In vitro stability studies exhibited RCP of more than 90% in serum at 37°C after 120 hours of radioiodination. In vitro cell binding with 131 I-trastuzumab in HER2+ cells showed binding of 28% to 35% which was inhibited significantly, with unlabeled trastuzumab confirming its specificity. Kd value of 131 I-trastuzumab was 0.5 nM, while its immunoreactivity was more than 80%. Uptake of more than 12% and retention were observed in the tumors up to 120 hours p.i. 131 I-trastuzumab prepared in-house-exhibited RCP of more than 98%, excellent immunoreactivity, affinity to HER2+ cell lines and good tumor uptake thereby indicating its potential for further evaluation in HER2+ breast cancers.