Preparation and evaluation of radiolabeled acetaminosalol microspheres: A new potential selective radiotracer for ulcerative colitis early diagnosis.

Acetaminosalol labeling reaction with technetium-99m was optimized, and the radiocomplex was obtained in a high radiochemical yield of 98.9 ± 0.6% and high stability (>30 h). The tracer was characterized, and its binding to the PPARγ receptor was assessed in silico. To reduce radiation exposure to non-target organs and increase accumulation in the colon, the tracer was formulated as pH-sensitive microspheres with a mean particle size of 201 ± 2.1 µm, a polydispersity index of 0.18, a 25.3 ± 3.6 zeta potential, and 98.6 ± 0.33% entrapment efficiency. The system suitability was assessed in vivo in normal and ulcerative rats, and the biodistribution profile in the colon showed 56.5 ± 1.4% localization within 4 h. Blocking study suggested the selectivity of the tracer to the target receptor. Overall, the reported data encouraged the potential use of the labeled microspheres to target ulcerative colitis.

Synthesis and biological evaluation of [131I]iodocarvedilol as a potential radiopharmaceutical for heart imaging.

The optimization of the radiolabeling yield of carvedilol with iodine-131 was described. Dependence of the labeling yield of [131I]iodocarvedilol on the concentration of carvedilol, chloramine-T content, pH of the reaction mixture and reaction time was studied in details. Carvedilol was labeled with iodine-131 at pH 6 with a labeling yield of 92.6 ± 2.77% by using 100 µg carvedilol, 200 µg chloramin-T (CAT) and 30 min reaction time. The formed [131I]iodocarvedilol was nearly stable for a time up to one day. Biodistribution of [131I]iodocarvedilol was investigated in experimental animals. [131/123I]iodocarvedilol was located in the heart with a concentration of 19.6 ± 0.41% of the injected dose at 60 min post injection. It has a high heart uptake and heart to liver ratio, both of which are beneficial for high-quality SPECT (single-photon emission computerized tomography) myocardial imaging. [131/123I]iodocarvedilol solve most the drawbacks of the FDA (Food and Drug Administration) approved 99mTc-sestamibi.

99mTc-linezolid as a radiotracer for brain abscess: Labeling, in silico docking, and biodistribution studies.

Brain abscess is a life-threatening condition that requires a timely and accurate diagnosis. In this study, linezolid, an oxazolidinone antibiotic, was labeled with technetium-99m according to the stannous chloride method. The labeling reaction factors were studied and optimized to achieve a high yield (97.4 ± 2.3%). The 99mTc-linezolid was radio- and physico-chemically characterized to assess its suitability as a radiopharmaceutical for the brain. In-silico docking to target peptidyltransferase showed an optimal binding fit (energy = -66.6 Kcal/mol). The complex was biologically evaluated in-vitro using binding assays in alive and heat-killed bacteria and in-vivo in an MRSA brain infection model. All results suggested that the labeled complex could potentially be a new nuclear imaging agent to diagnose and localize brain abscesses specifically.

Radio-iodination and biological evaluation of pentoxifylline as a novel probe for diagnosis of intermittent claudication.

The diagnosis of intermittent claudication (IC) is challenging. Imaging with radiopharmaceuticals provides a new method for detecting acute IC. Pentoxifylline improves blood flow to ischemic tissues via increasing erythrocyte elasticity and inhibiting platelet aggregation. Pentoxifylline was radio-iodinated with radioiodine-131 (131I) through a direct electrophilic substitution reaction. Furthermore, various factors that might influence the radiolabeling strategy were investigated. The radiochemical yield of [131I]iodopentoxiphyline was evaluated by using paper chromatography and HPLC methods. The biodistribution pattern of [131I]iodopentoxiphyline was studied, where Swiss albino mice was used as a model of acute limb ischemia-reperfusion. The maximum radiochemical yield of pentoxifylline was found to be 94.11 ± 2.35%. The biodistribution findings revealed that [131I]iodopentoxiphyline was significantly deposited at the ischemic site (left hind limbs), with encouraging target/non-target (T/NT) ratios. At 0.25 and 1 h post injection, the uptake of [131I]iodo-pentoxifylline was 5.30 ± 0.30 and 9.98 ± 1.12%, respectively. Also, the maximum T/NT ratio for [131I]iodo-pentoxifylline (9.45 ± 0.26) was obtained at 0.25 h post injection. Due to safety and selectivity, [131I]iodo-pentoxifylline may be a good prospective diagnostic tool for early identification of IC. Moreover, the outcome of this study can be expected to apply to I-123 as well.

Radioiodination, nasal nanoformulation and preliminary evaluation of isovanillin: A new potential brain cancer-targeting agent.

Brain cancer is a challenging disease to treat using conventional approaches. The present investigation aimed to develop a radiopharmaceutical targeting brain cancer based on natural isovanillin. Different parameters were optimized, resulting in high radiolabeling efficiency (97.3 ± 1.2%) and good stability (<48 h). The tracer was formulated for intranasal delivery in a chitosan nanoparticles system with a mean particle size of 141 ± 2 nm, a polydispersity index of 0.23 ± 0.02, and a zeta potential of -17.4 ± 0.3 mV to enhance nasal uptake and surmount the blood-brain barrier. The system was characterized and assessed in-vitro for suitability and specificity and evaluated in-vivo in normal and tumorized mice. The biodistribution profile in brain tumor showed 20.5 ± 0.4 %ID/g localization and cancer cell targeting within 60 min. Improvement in brain tumor uptake resulted from both the nanoformulation and nasal administration of iodoisovanillin. Overall, the reported results encourage the potential use of the nanoformulated labeled compound as an anticancer agent.