Radiocomplexation and biological evaluation of nemonoxacin in mice infected with multiresistant Staphylococcus aureus and penicillin-resistant Streptococci

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.

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.

Preparation and preliminary evaluation study of [131I]iodocolchicine-gallic-AuNPs: a potential scintigraphic agent for inflammation detection

BACKGROUND

Nanomedicine offers great potential for scintigraphic diagnostic imaging with lower risk and higher quality compared to other traditional techniques.

OBJECTIVES

This work aimed to develop and evaluate gold nanoparticles combined with gallic acid (gallic-AuNPs) and [¹³¹I]iodocolchicine as a scintigraphic probe for inflammation.

METHODS

[¹³¹I]iodocolchicine-gallic-AuNPs were synthesized via chemical reduction method where gallic acid was used as reducing agent and [¹³¹I]iodocolchicine was used as stabilizing agent. Then a characteristic profile for the synthesized nano-platform was performed including size analysis, zeta potential, radiochemical yield and in-vivo biodistribution in inflammation bearing mice.

RESULTS AND CONCLUSION

This platform was successfully synthesized with good stability, appropriate particle size (10 nm diameter for AuNPs), and high radiochemical purity for [¹³¹I]iodocolchicine (96.79%). The in-vivo study indicated that [¹³¹I]iodocolchicine-gallic-AuNPs accumulated with a high target to non-target ratio in intravenous injection and high retention value in intra-inflammation injection in inflammation model. The obtained data supported the usefulness of the new platform ([¹³¹I]iodocolchicine-gallic-AuNPs) as a tracer for the detection and localization of inflammation.

Radiolabeling, characterization and preclinical evaluation of plazomicin: a potential tracer for bacterial infection

In this study, ^99m Tc-plazomicin, a new radio-antibiotic complex, was prepared specifically for bacterial infection localization and monitoring. Factors affecting the labeling reaction were studied and optimized to obtain a high yield (98.8 ± 0.2%). In-silico, radiochemical and physicochemical characterization and biodistribution were performed to assess the complex aptness as a radiopharmaceutical. The complex was biologically evaluated in-vitro using bacteria and in-vivo using different inflammation models (sterile, bacterial, and fungal). Uptake in the bacterial model was highest (7.8 ± 0.3%). Results indicated that the technetium label did not alter the antibiotic biological behavior and backed the usefulness of ^99m Tc-plazomicin as a potential tracer.

99m Tc-labeled antibiotics for infection diagnosis: Mechanism, action, and progress

Discovery of penicillin marked a turning point in the history of infection therapy which also led to the emergence of bacterial resistance. It is now 100 years to fight with ever-muted variants of pathogens by developing more and more antibiotics. Since 1987 to todate, no successful class of antibiotic was introduced; this three decade period is known as "the discovery void" period. While, the clinically approved antibiotics are gradually dying in front of bacterial resistance due to which bacterial infections are appearing leading cause of death and disability. Nuclear medicine imaging technique is the strongest modality to diagnose and follow-up of deep-seated and complicated infections. However, the selection of radiolabeled antimicrobial agents plays critical role in gaining sensitivity and specificity of the imaging results. This review comprises of two main sections; first section explains antibiotic targets, and second section explains the imaging efficacy of ^99m Tc-labeled antimicrobial agents against bacterial infection along with the emphasis on progress and update of ^99m Tc-labeled antibiotics as infection imaging probes. The review, in conclusion, could be an acceleration for radiopharmaceutical chemists for designing and developing ^99m Tc-labeled antimicrobial agents to improve infection imaging quality.

Recent advances in the synthetic and medicinal perspective of quinolones: A review

In the modern scenario, the quinolone scaffold has emerged as a very potent motif considering its clinical significance. Quinolones possess wide range of pharmacological activities such as anticancer, antibacterial, antifungal, antiprotozoal, antiviral, anti-inflammatory, carbonic anhydrase inhibitory and diuretic activity etc. The versatile synthetic approaches have been successfully applied and several of the resulted synthesized compounds exhibit fascinating biological activities in numerous fields. This has prompted to discover quinolone-based analogues among the researchers due to its great diversity in biological activities. In the past few years, various new, efficient and convenient synthetic approaches (including green chemistry and microwave-assisted synthesis) have been designed and developed to synthesize diverse quinolone-based scaffolds which represent a growing area of interest in academic and industry as well as to explore their biological activities. In this review, an attempt has been made by the authors to summarize (1) One of the most comprehensive listings of quinolone-based drugs or agents in the market or under various stages of clinical development; (2) Recent advances in the synthetic strategies for quinolone derivatives as well as their biological implications including insight of mechanistic studies. (3) Further, the biological data is correlated with structure-activity relationship studies to provide an insight into the rational design of more active agents.

Labelling, molecular modelling and biological evaluation of vardenafil: a potential agent for diagnostic evaluation of erectile dysfunction

^99mTc-tricarbonyl-vardenafil was specifically radiosynthesized for diagnostic evaluation of erectile dysfunction with a radiochemical yield ~97.2%. It was stable in saline up to 15h and in serum for more than 6h. The radiocomplex was lipophilic with a partition coefficient ~1.32 and plasma protein binding 72-76%. Its structure was determined using molecular mechanics and confirmed by NMR. In-silico docking to its target PDE₅ enzyme was performed. The radiocomplex inhibitory activity was assessed and its IC₅₀ was 0.7nM. Biodistribution in normal rats and biological evaluation in rat models of erectile dysfunction were performed. The results strongly suggested that ^99mTc-tricarbonyl-vardenafil is a good candidate to image erectile dysfunction in humans.

Preparation, characterization and evaluation of (186) Re-idarubicin: a novel agent for diagnosis and treatment of hepatocellular carcinoma

Hepatocellular carcinoma is a widely prevalent cancer, and hence, the development of radiopharmaceuticals for its management is an important issue. In the current investigation, the complexation of idarubicin with (186) Re was studied. Optimum labelling conditions were found to be 4 mg idarubicin, 1.5 mg stannous chloride dihydrate and ~70 MBq Re-186 at pH 7. The complex showed ~97.6% RCY value at 20 min and remained stable up to 24 h in the presence of 2.5 mg ascorbic acid. Molecular docking was performed to evaluate the complex binding to its target DNA-human topoisomerase II complex. Result of the in vivo evaluation showed that the complex tends to preferentially localize in cancerous tissues. The in vitro cell growth inhibition assay showed that the effect of the (186) Re-idarubicin was stronger than the effect of cold idarubicin, which strongly suggested that its cytotoxicity was mainly because of radiotoxicity rather than chemotherapeutic activity.