Preparation and evaluation of 99mTc-cefuroxime, a potential infection specific imaging agent: a reliable thin layer chromatographic system to delineate impurities from the 99mTc-antibiotic.

Technetium-99m labelled cefuroxime, a second-generation cephalosporin antibiotic and potential bacteria specific infection imaging agent was evaluated. A good radiochemical purity (95%) of the labelled product was obtained after filtering the reaction mixture through a 0.22 µm filter. Scintigraphy study of the purified product showed uptake in infectious lesions 45 min after injection and abscess-to-muscle ratios were found to be 1.80, 1.85 and 1.88 at 45 min, 1.5 hr and 3 hr, respectively. A versatile and reliable chromatographic technique to assess the radiochemical purity of (99m)Tc-cefuroxime has also been described.

Synthesis and evaluation of (99m)Tc-moxifloxacin, a potential infection specific imaging agent.

To synthesize and evaluate a (99m)Tc labeled fluroquinolone, moxifloxacin as a potential bacteria specific infection imaging agent. A radiolabeling formulation including moxifloxacin, [Moxicip(TM) injection, Cipla] (4mg), sodium pertechnetate and stannous chloride (5microg) gave the best radiolabeling efficiency and moderately stable labeled (99m)Tc moxifloxacin. Quality control analysis was performed by ITLC. Rats and rabbit with infectious intramuscular lesions induced in either thigh with E. Colli were used for studying biodistribution and scintigraphic imaging of the labeled product. Imaging of an infected thigh of a rabbit was performed with a gamma-camera at various intervals. A good radiolabeling efficiency (90-95%) was obtained within 5min. No purification of the labeled product was done. Labeled product retained its radiochemical purity upto 85% even at 3h. Scintigraphy showed uptake in infectious lesions at 30min after injection, which remains constant upto 3h study. Abscess-to-muscle ratios were 1.60, 1.62, 1.74 and 1.75 at 30min, 1, 2 and 3h, respectively. Thus, (99m)Tc moxifloxacin, a new potential radiopharmaceutical has been developed for infection imaging agent.

Assessment of the effect of Bacopa monnieri (L.) Wettst. extract on the labeling of blood elements with technetium-99m and on the morphology of red blood cells / Avaliação do efeito do extrato de Bacopa monnieri (L.) Wettst. na marcação de elementos sanguíneos com tecnécio-99m e na morfologia de células vermelhas do sangue

Bacopa monnieri (L.) Wettst. (BM), a traditional Ayurvedic medicine, used for centuries as a memory enhancing, anti-inflammatory, antipyretic, sedative and antiepileptic agent. BM extract have been extensively investigated by several authors for their neuropharmacological effects. In nuclear medicine, red blood cells (RBC) labeled with technetium-99m (99mTc) have several clinical applications. However, data have demonstrated that synthetic or natural drugs could modify the labeling of RBC with 99mTc. As Bacopa monnieri is extensively used in medicine, we evaluated its influence on the labeling of RBC and plasma proteins using technetium-99m (99mTc). This labeling procedure depends on a reducing agent and usually stannous chloride is used. Blood was incubated with BM extracts. Stannous chloride solution and 99mTc were added. Blood was centrifuged and plasma (P) and blood cells (BC) were isolated. Samples of P or BC were also precipitated, centrifuged and insoluble fraction (IF) and soluble fraction (SF) were separated. The percentage of radioactivity ( percentATI) in BC, IF-BC and IF-P were calculated. The percentATI significantly decreased on BC from 95.53±0.45 to 35.41±0.44, on IF-P from 80.20±1.16 to 7.40±0.69 and on IF-BC from 73.31±1.76 to 21.26±1.40. The morphology study of RBC revealed important morphological alterations due to treatment with BM extracts. We suggest that the BM extract effect could be explained by an inhibition of the stannous and pertechnetate ions or oxidation of the stannous ion or by damages induced in the plasma membrane.

Bacopa monnieri (L.) Wettst. (BM), uma planta tradicional da medicina ayurvédica, é usada por séculos para problemas de memória, antiinflamatória, antitérmica, sedativa e como agente anti-epiléptico. O extrato BM têm sido extensivamente investigada por diversos autores por seus efeitos neurofarmacológicas. Na medicina nuclear, os glóbulos vermelhos (RBC) marcados com tecnécio-99m (99mTc) tem várias aplicações clínicas. Entretanto, os dados demonstraram que drogas sintéticas ou naturais podem modificar a marcação de hemácias com 99mTc. Como Bacopa monnieri é amplamente utilizado em medicina, foi avaliada a sua influência na marcação de hemácias e proteínas plasmáticas com tecnécio-99m (99mTc). Este procedimento de marcação depende de um agente redutor e normalmente o cloreto estanoso é usado. Sangue foi incubado com os extratos BM. Solução de cloreto estanoso e 99mTc foram adicionados. O sangue foi centrifugado e o plasma (P) e células sangüíneas (CS) foram isolados. Amostras de P ou BC também foram precipitadas, centrifugadas e fração insolúvel (FI) e fração solúvel (FS) foram separadas. A porcentagem de radioatividade ( por centoATI) em BC, IF-BC e SE-P foram calculados. A As por cento ATI diminuiu significativamente em BC de 95,53±0,45-35,41±0,44, no IF-P de 80,20±1,16 para 7,40±0,69 e no IF-BC em 73,31±1,76-21,26±1,40. O estudo da morfologia de hemácias revelou alterações morfológicas importantes devido a tratamentos com extratos BM. Sugere-se que a ação do extrato BM poderia ser explicada por uma inibição dos íons estanoso e pertecnetato ou oxidação do íon estanoso ou por danos na membrana plasmática.

Synthesis, radiolabeling and biological evaluation of a neutral tripeptide and its derivatives for potential nuclear medicine applications.

Peptides are important regulators of growth and cellular functions not only in normal tissue but also in tumors. So they are becoming radioligands of increasing interest in nuclear oncology for targeted tumor diagnosis and therapy. So development of new peptide radiopharmaceuticals is becoming one of the most important areas in nuclear medicine research. A small tripeptide derivative NH(2)PhePheCys was synthesized by Fmoc solid phase peptide synthesis using an automated synthesizer. The oxidized form, i.e. NH(2)PhePheCysCysPhePheNH(2,) was also prepared by iodine oxidation method from NH(2)PhePheCys(ACM). The ligands were analyzed by HPLC and mass spectroscopy. They were radiolabeled with (99m)Tc using SnCl(2). In vitro analytical studies and biological characterizations were performed using the peptide radiopharmaceuticals. Images taken under gamma camera showed very high uptake in the liver, lung and spleen. Significant uptake was also observed in bone marrow and brain for (99m)Tc-NH(2)PhePheCys. Metabolites were produced in vivo when the radiopharmaceuticals were injected intravenously and were identified from rat brain and liver homogenate studies. Clearance through kidney did not show any evidence of breaking of the labeled compounds and formation of free (99m)Tc. Radiopharmaceuticals prepared using tripeptide and hexapeptide ligands were transported into the brain through blood brain barrier depending on the size and sequence characteristics. Using this property of peptide new derivatives can be prepared to develop (99m)Tc radiopharmaceuticals for imaging normal brain tissues as well as for diagnosing various brain disorders.

Comparative evaluation of Tc-99m cystine and Tc-99m MAG3 in normals and patients with renal functional impairment.

Tc-99m cystine has been proved to be a good renal agent in animals for morphologic as well as the functional status of the kidney. In this study, we compared Tc-99m cystine with Tc-99m mercaptoacetyltriglycine, which is used for evaluation of renal function in normal patients, and those with various degrees of renal functional impairment. The clearance values and static images are compared with Tc-99m mercaptoacetyltriglycine. The results show that Tc-99m cystine has good radiopharmaceutical characteristics suitable for evaluation of both renal function as well as morphology.