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1.
Mol Biol Rep ; 50(11): 8827-8837, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37658928

RESUMO

BACKGROUND: RNA (ribonucleic acid) antisense is developing as a possible treatment option. As an RNA, miR-34a is involved in P53 function and cancer cell apoptosis. Although the therapeutic applications of miRNAs have several limitations, such as structural instability and susceptibility to nucleases. To resolve these issues, this study aims to apply exosomes as a delivery vehicle for miR-34a. AIMS: This study aims to create a cell factory to generate miR34a-enriched exosomes. The produced nanoparticles act as a delivery system and improve the structural stability of miR34a. METHODS: First exosome specific sequences were inserted into miR34a. The resulting miR34a oligonucleotide was transduced HEK293T cells genome with a lentiviral system. In the structure of miR34a oligonucleotide, six nucleotides were substituted to increase its packaging rate into exosomes. To maintain the secondary structure, stability, and expression of the miRNA gene, changes to the miR34a oligonucleotide were made using PCR (polymerase chain reaction) Extension. The forward-34a (5-TGGGGAGAGGCAGGACAGG-3) and Reverse-34a primers (5-TCCGAAGTCCTGGCGTCTCC-3) were used for amplification of the miR34a gene from DNA. RESULTS: The results confirmed that the changes in miR34a oligonucleotide do not affect its secondary structure. The energy level of the manipulated miR34a oligonucleotide was kept the same compared to the original one. Moreover, the loading of miR34a to the exosomes was increased. CONCLUSION: Our findings revealed that normal HEK293T did not express miR34a. However, lentiviral transduced miR34a oligonucleotide induced the loading of miR34a into the exosome. Moreover, replacing six nucleic acids in the 3' end of miR34a increased the loading of miR34a to exosome.


Assuntos
Exossomos , MicroRNAs , Humanos , Lentivirus/genética , Células HEK293 , Exossomos/genética , MicroRNAs/genética , Oligonucleotídeos
2.
Bioorg Chem ; 135: 106486, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36965286

RESUMO

Glioblastoma multiform (GBM) is one of the most aggressive tumors of the central nervous system in humans. GBM overexpresses serotonin-7 receptors (5-HT7Rs); hence, this study aims to develop 5-HT7R targeted radiotracers. Aryl piperazine derivatives can act as ligands for 5-HT7R. Therefore, compounds 6 and 7 as 1-(3-nitropyridin-2-yl)piperazine derivatives were synthesized and radiolabeled with 99mTcN2+ core. Radiolabeled 6 and 7 (99mTcN-[6] and 99mTcN-[7]) were prepared with high radiochemical purity (RCP > 96%). They displayed high affinity toward U-87 MG cell line 5-HT7R. The calculated Ki for 99mTcN-[7] was lower than that of 99mTcN-[6] (14.85 ± 0.32 vs 22.57 ± 0.73 nM) which indicates the higher affinity of 99mTcN-[7] toward 5-HT7R. A molecular docking study also confirmed the binding of these radiotracers to 5-HT7R. The biodistribution study in normal mice revealed that 99mTcN-[7] has the highest brain accumulation at 30 min post-injection (0.54 ± 0.12 %ID/g) while the uptake of 99mTcN-[6] is much lower (0.14 ± 0.02 %ID/g). The biodistribution study in the xenograft model confirms that the radiotracers recognize the tumor site. 99mTcN-[6], and 99mTcN-[7] showed the highest tumor uptake at 1-hour post-injection (5.44 ± 0.58 vs 4.94 ± 1.65 %ID/g) and tumor-to-muscle ratios were (4.61 vs. 5.61). The injection of pimozide blocks the receptors and significantly reduces the tumor-to-muscle ratios at 1-hour post-injection to 0.81 and 0.31, respectively. In correlation with in vitro study, 99mTcN-[6] and 99mTcN-[7] visualize the tumor site in U-87 MG glioma xenografted nude mice and display the tumor-to-muscle ratios of 7.05 and 6.03.


Assuntos
Glioma , Compostos de Organotecnécio , Humanos , Camundongos , Animais , Compostos de Organotecnécio/química , Distribuição Tecidual , Camundongos Nus , Simulação de Acoplamento Molecular , Serotonina/metabolismo , Piperazinas , Linhagem Celular Tumoral
3.
Mol Pharm ; 18(6): 2360-2374, 2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34027660

RESUMO

With a poor prognosis, glioblastoma multiforme is the most aggressive tumor of the central nervous system in humans. The aim of this study was to develop novel tracers for the tumor targeting and imaging of overexpressed serotonin-7 receptors (5-HT7Rs) in U-87 MG glioma xenografted nude mice. Two phenylpiperazine derivatives named as PHH and MPHH were designed, and the corresponding radiotracers 99mTc-PHH and 99mTc-MPHH were synthesized in high radiochemical purity (>95%). 99mTc-MPHH showed a higher affinity to 5-HT7Rs on U-87 MG cells compared to 99mTc-PHH. In biodistribution studies, the radiocomplexes showed good brain uptake at 15 min combined with good radioactivity retention in the brain for 240 min. Regional rabbit brain studies indicated a higher radioactivity concentration in the hippocampus and diencephalon than in the cerebellum. Compared to 99mTc-MPHH, the 99mTc-PHH exhibited a significantly increased tumor uptake at 15 and 60 min, but the rapid blood clearance of 99mTc-MPHH led to enhanced tumor-to-muscle ratios at 240 min. A significant reduction in tumor uptake 60 min after an injection of pimozide (5-HT7 receptor antagonist) confirms the tumor uptake was receptor-mediated specifically. The tumor-to-contralateral muscle tissue ratio of 99mTc-PHH and 99mTc-MPHH in nude mice with U-87 MG xenograft was measured (5.25 and 4.65) at 60 min as well as (6.25 and 6.76) at 240 min, respectively.


Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Glioblastoma/diagnóstico por imagem , Piperazinas/administração & dosagem , Compostos Radiofarmacêuticos/administração & dosagem , Receptores de Serotonina/metabolismo , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Encéfalo/patologia , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Glioblastoma/patologia , Humanos , Ligantes , Masculino , Camundongos , Pimozida/administração & dosagem , Piperazinas/síntese química , Piperazinas/farmacocinética , Tomografia por Emissão de Pósitrons/métodos , Coelhos , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/farmacocinética , Antagonistas da Serotonina/administração & dosagem , Tecnécio , Distribuição Tecidual/efeitos dos fármacos , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Ensaios Antitumorais Modelo de Xenoenxerto
4.
Mol Biol Rep ; 48(8): 1-14, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34357550

RESUMO

INTRODUCTION: Radiotherapy is one of the most common types of cancer treatment modalities. Radiation can affect both cancer and normal tissues, which limits the whole delivered dose. It is well documented that radiation activates phosphatidylinositol 3-kinase (PI3K) and AKT signaling pathway; hence, the inhibition of this pathway enhances the radiosensitivity of tumor cells. The mammalian target of rapamycin (mTOR) is a regulator that is involved in autophagy, cell growth, proliferation, and survival. CONCLUSION: The inhibition of mTOR as a downstream mediator of the PI3K/AKT signaling pathway represents a vital option for more effective cancer treatments. The combination of PI3K/AKT/mTOR inhibitors with radiation can increase the radiosensitivity of malignant cells to radiation by autophagy activation. Therefore, this review aims to discuss the impact of such inhibitors on the cell response to radiation.


Assuntos
Neoplasias/radioterapia , Tolerância a Radiação/fisiologia , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Inibidores de MTOR/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo
5.
Regul Toxicol Pharmacol ; 112: 104591, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32006673

RESUMO

Accurate assessment of the HER2 expression is an essential issue for predicting response to anti-HER2 therapy in breast cancer patients. The aim of this study was to evaluate 99mTc-HYNIC-(Ser)3-LTVPWY (99mTc-HYNIC-LY) peptide as a novel HER2-targeted radiolabeled peptide in healthy mice to examine the applicability of this imaging agent in a first-in-human clinical trial. To this end, pharmacokinetic and dosimetry studies were performed according to the ICH guideline M3 (R2) with 99mTc-HYNIC-LY. To estimate the radiation-absorbed doses in humans, the accumulated activity in each mouse organ was calculated based on biodistribution data. In addition, toxicology assessment was performed based on mortality events, body weights, and serum biochemical, hematological, and histopathological assays. The pharmacokinetic study showed rapid blood clearance. Based on the results of biodistribution study, the highest radioactivity was observed in the kidneys. The projected absorbed doses to the kidneys, liver, lungs, stomach, and spleen were obtained as 1.70E-02, 1.42E-02, 1.02E-02, 8.62E-03, and 8.34E-03 mSv/MBq, respectively. The results also revealed that serum biochemical and hematological parameters were in the normal range. No significant morphologic alterations were observed in the liver, kidneys, and spleen tissues. Consequently, the results were indicative of the suitability of 99mTc-HYNIC-LY peptide for advancement to a first-in-human clinical trial.


Assuntos
Compostos de Organotecnécio/farmacocinética , Peptídeos/farmacocinética , Compostos Radiofarmacêuticos/farmacocinética , Receptor ErbB-2/antagonistas & inibidores , Administração Intravenosa , Animais , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Compostos de Organotecnécio/sangue , Peptídeos/sangue , Radiometria , Compostos Radiofarmacêuticos/sangue , Receptor ErbB-2/metabolismo , Distribuição Tecidual
6.
Ann Nucl Med ; 38(2): 139-153, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38032496

RESUMO

BACKGROUND: The 5-hydroxytryptamine receptor (5-HTR) family includes seven classes of receptors. The 5-HT7R is the newest member of this family and contributes to different physiological and pathological processes. As a pathology, glioblastoma multiform (GBM) overexpresses 5-HT7R; hence, this study aims to develop radiolabeled aryl piperazine derivatives as 5-HT7R imaging agents.  METHODS: Compounds 6 and 7 as 1-(3-nitropyridin-2-yl)piperazine derivatives were radiolabeled with fac-[99mTc(CO)3(H2O)3]+ and 99mTc(CO)3-[6] and 99mTc(CO)3-[7] were obtained with high radiochemical purity (RCP > 94%). The stability of the radiotracers was evaluated in both saline and mouse serum. Specific binding on different cell lines including U-87 MG, MCF-7, SKBR3, and HT-29 was performed. The biodistribution of these radiotracers was evaluated in normal and U-87 MG Xenografted models. Finally, 99mTc(CO)3-[6] and 99mTc(CO)3-[7] were applied for in vivo imaging in U-87 MG Xenografted models. RESULTS: Specific binding study indicates that 99mTc(CO)3-[6] and 99mTc(CO)3-[7] can recognize 5-HT7R of U87-MG cell line. The biodistribution study in normal mice indicates that the brain uptake of 99mTc(CO)3-[6] and 99mTc(CO)3-[7] is the highest at 30 min post-injection (0.8 ± 0.25 and 0.64 ± 0.18%ID/g, respectively). The data of the biodistribution study in the U87-MG xenograft model revealed that these radiotracers could accumulate in the tumor site, and the highest tumor uptake was observed at 60 min post-injection (3.38 ± 0.65 and 3.27 ± 0.5%ID/g, respectively). The injection of pimozide can block the tumor's radiotracer uptake, indicating the binding of these radiotracers to the 5-HT7R. The imaging study in the xenograft model also confirms the biodistribution data. The acquired images clearly show the tumor site, and the tumor-to-muscle ratio for 99mTc(CO)3-[6] and 99mTc(CO)3-[7] at 60 min was 3.33 and 3.88, respectively.  CONCLUSIONS: 99mTc(CO)3-[6] and 99mTc(CO)3-[7] can visualize tumor in the U87-MG xenograft model  due to their affinity toward 5-HT7R.


Assuntos
Neoplasias , Serotonina , Camundongos , Humanos , Animais , Distribuição Tecidual , Compostos Radiofarmacêuticos , Piperazinas , Tecnécio/química , Linhagem Celular Tumoral
7.
Ann Nucl Med ; 37(7): 400-409, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37115407

RESUMO

BACKGROUND: Peptide receptor radionuclide therapy (PRRT) has evolved in cancer therapy and diagnosis. LTVSPWY, as a peptide, can target HER2 receptor; on the other hand, 177Lu emits ß- which is helpful for cancer therapy. The radiolabeling of LTVSPWY with 177Lu results in a therapeutic agent (177Lu-DOTA-LTVSPWY) capable of cancer treatment. METHODS: 177Lu-DOTA-LTVSPWY was prepared with high radiochemical purity (RCP). The stability was investigated in saline and human serum. The radiotracer affinity toward the SKOV-3 cell line with overexpression of the HER2 receptor was evaluated. Then the impact of the radiotracer on the colony formation of the SKOV-3 cell line was investigated with colony assay. Moreover, the biodistribution of this radiotracer in SKOV-3 xenograft tumor-bearing nude mice were also studied to determine the radiotracer accumulation in the tumor site. The mice were treated with 177Lu-DOTA-LTVSPWY and subjected to histopathological evaluation. RESULTS: The RCP of 177Lu-DOTA-LTVSPWY after radiolabeling and stability tests was more than 97.7%. The radiotracer displayed high affinity toward the SKOV-3 cell line (KD = 6.6 ± 3.2 nM). Treatment of the SKOV-3 cell line with the radiotracer reduces the SKOV-3 colony survival to less than 3% for 5 MBq of the radiotracer. Tumor-to-muscle (T/M) ratio is the highest at 48 h and 1 h post-injection (2.3 and 4.75, respectively). The histopathological study also confirms the cellular damage to the tumor tissue. CONCLUSIONS: 177Lu-DOTA-LTVSPWY can recognize HER2 receptors in vivo and in vitro; hence, it can serve as a therapeutic agent.


Assuntos
Neoplasias , Humanos , Camundongos , Animais , Distribuição Tecidual , Camundongos Nus , Neoplasias/diagnóstico por imagem , Neoplasias/radioterapia , Compostos Radiofarmacêuticos/uso terapêutico , Linhagem Celular Tumoral , Lutécio/uso terapêutico
8.
Curr Drug Metab ; 23(1): 82-87, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35049428

RESUMO

BACKGROUND: HER2 over-expression plays a crucial role in the cancer treatment protocol. This study evaluates the effectiveness of organic anion and cation transport inhibitors and substrate on the tumor uptake of 99mTc- HYNIC-(Ser)3-LTVPWY radiotracer in SKOV-3 tumor-bearing nude mice. METHODS: Before the injection of the radiolabeled peptide, SKOV-3 tumor-bearing nude mice were treated with furosemide, cimetidine, para-amino hippuric acid, and saline. The inhibition effects of the organic anion and cation transport inhibitors were compared with the control group. In both treatment and control groups, the tumor and renal accumulation of radiopeptide in mice bearing SKOV-3 tumors were assessed in biodistribution and SPECT imaging studies. RESULTS: The biodistribution and imaging results suggested that all treated groups showed a higher tumor and higher normal tissue radioactivity compared to the control group. According to the tumor imaging study, the furosemidetreated group had slightly better tumor uptake and a higher tumor to muscle uptake ratio than other treatment groups. CONCLUSION: Administration of furosemide (an OAT inhibitor) increased radioactivity accumulation in the kidneys and blood and improved tumor radioactivity uptake. PAH (an anion transporter substrate) and cimetidine (an OCT inhibitor) have a minor effect on the accumulation of radioactivity in the kidneys and the acquired images.


Assuntos
Furosemida , Neoplasias , Animais , Cátions , Cimetidina/farmacologia , Humanos , Transporte de Íons , Rim , Camundongos , Camundongos Nus , Peptídeos/farmacocinética , Distribuição Tecidual
9.
Nucl Med Commun ; 43(8): 945-951, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35754162

RESUMO

PURPOSE: Imaging of glioblastoma multiform (GBM) tumor using 68 -Galium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaceticacid-Ser-Ser-Ser-Leu-Thr-Val-Ser-Pro-Trp-Tyr ( 68 Ga-DOTA-(Ser)3-LTVSPWY) as a PET radiotracer for HER2 receptor due to fact that this receptor plays a pivotal role in the tumorigenesis and tumor progression in a wide range of cancer. METHODS: 68 Ga-DOTA-(Ser) 3 -LTVSPWY was produced with high radiochemical purity. The affinity and specificity of this radiotracer toward HER2 receptor on the surface of glioma glioblastoma (U-87 MG) cell line were evaluated. Furthermore, the biodistribution and PET imaging of this radiolabeled peptide were investigated on xenografted U-87 MG tumor-bearing mice. RESULTS: The in-vitro specific binding study revealed that the 68 Ga-DOTA-(Ser) 3 -LTVSPWY binds to different cell lines with respect to their level of HER2 expression. The calculated K D and B max of radiolabeled peptide toward U-87 MG cell line were 5.5 ± 2.4 nmol/l and (2.4 ± 0.3) × 10 5 receptors per cell, respectively. The highest tumor uptake was observed at 30-min postinjection, whereas the tumor-to-muscle ratio was about four-fold. The acquired PET images distinctively show tumor site, which was blocked with excess nonlabeled peptide that revealed specific in-vivo targeting of 68 Ga-DOTA-(Ser) 3 -LTVSPWY for glioma. CONCLUSION: 68 Ga-DOTA-(Ser) 3 -LTVSPWY specifically recognizes HER2 receptors and could be a potential candidate for GBM imaging.


Assuntos
Glioblastoma , Glioma , Animais , Linhagem Celular Tumoral , Radioisótopos de Gálio , Glioblastoma/diagnóstico por imagem , Compostos Heterocíclicos com 1 Anel , Camundongos , Oligopeptídeos , Peptídeos , Tomografia por Emissão de Pósitrons/métodos , Distribuição Tecidual
10.
Iran J Pharm Res ; 20(1): 141-152, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34400948

RESUMO

The human epidermal growth factor receptor (HER) family plays pivotal roles in physiologic and pathologic conditions (such as tumor growth, proliferation, and progression in multiple epithelial malignancies). All the family members are considered tyrosine kinase, while HER3 as a member of this family shows no intrinsic tyrosine kinase. HER3 is called 'pseudokinase' because it undergoes heterodimerization and forms dimers such as HER2-HER3 and HER1 (EGFR)-HER3. The exact role of HER3 in cancer is still unclear; however, the overexpression of this receptor is involved in the poor prognosis of malignancies. To that end, different studies investigated the development of radiotracers for imaging of HER3. The main focus of this review is to gather all the studies on developing new radiotracers for imaging of HER3.

11.
Nucl Med Commun ; 41(9): 841-847, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32796471

RESUMO

Myocardial perfusion imaging (MPI) as an imaging modality plays a key role in the monitoring of patients with cardiovascular disease. MPI enables the assessment of cardiovascular disease, the effectiveness of therapy, and viable myocardial tissue. However, MPI suffers from some downfalls and limitations, which can influence its clinical applications. These limitations can arise from the patient's condition, equipment, or the actions of the technologist. In this review, we mainly focused on the different effective parameters on radioactivity uptake of organs including liver, intestines, stomach, and gall bladder and how they affect the quality of the acquired images in nuclear medicine. More importantly, we cover how different suggested medicines, foods and exercise alleviative this problem.


Assuntos
Artefatos , Suplementos Nutricionais , Coração/efeitos dos fármacos , Coração/diagnóstico por imagem , Imagem de Perfusão do Miocárdio/métodos , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Humanos , Radioatividade
12.
Eur J Pharm Sci ; 148: 105312, 2020 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-32198014

RESUMO

Exosomes represent unique features including nontoxicity, non-immunogenicity, biodegradability, and targeting ability that make them suitable candidates for clinical applications. Therefore, in this study, 99mTc-radiolabel HER2 targeted exosomes (99mTc-exosomes) were provided for tumor imaging. These exomes are obtained from genetically engineered cells and possessed DARPin G3 as a ligand for HER2 receptors. These exosomes were radiolabeled using fac-[99mTc(CO)3(H2O)3]+ synthon. The quality control showed high radiochemical purity (RCP) for 99mTc-exosomes (>96%). 99mTc-exosomes displayed a higher affinity toward SKOV-3 cells (higher HER2 expression) in comparison with MCF-7, HT29, U87-MG, A549 cell lines at different levels of HER2 expression. Trastuzumab (an antibody with a high affinity toward HER2) inhibited the binding of 99mTc-exosomes to SKOV-3 cells up to 40%. Biodistribution study in SKOV-3 tumor bearing nude mice confirmed the ability of 99mTc-exosomes for accumulation in the tumor. 99mTc-exosomes can visualize tumor in SKOV-3 tumor-bearing nude mouse. The blockage of HER2 receptors using trastuzumab (excessive amount) suggests the 99mTc-exosomes binding to the receptors and reduced the accumulation of 99mTc-exosomes in the tumor site. This suggest that 99mTc-exosomes interact with HER2 receptors and act through specific targeting.


Assuntos
Exossomos , Imagem Molecular/métodos , Receptor ErbB-2/metabolismo , Animais , Linhagem Celular Tumoral , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Nus , Compostos Radiofarmacêuticos , Distribuição Tecidual
13.
Curr Pharm Des ; 25(37): 3917-3926, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31480999

RESUMO

Combination of nanotechnology, biochemistry, chemistry and biotechnology provides the opportunity to design unique nanoparticles for tumor targeting, drug delivery, medical imaging and biosensing. Nanoparticles conjugated with biomolecules such as antibodies, peptides, vitamins and aptamer can resolve current challenges including low accumulation, internalization and retention at the target site in cancer diagnosis and therapy through active targeting. In this review, we focus on different strategies for conjugation of biomolecules to nanoparticles such as inorganic nanoparticles (iron oxide, gold, silica and carbon nanoparticles), liposomes, lipid and polymeric nanoparticles and their application in tumor targeting.


Assuntos
Sistemas de Liberação de Medicamentos , Nanopartículas , Neoplasias/tratamento farmacológico , Humanos , Nanotecnologia , Polímeros
14.
Curr Med Chem ; 26(12): 2166-2189, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-29637851

RESUMO

BACKGROUND: Alzheimer's disease (AD) is an age-related progressive neurodegenerative disease. Its prominent hallmarks are extracellular deposition of ß-amyloids (amyloid plaques), intracellular neurofibrillary tangles (NTFs), neurodegeneration and finally loss of cognitive function. Hence, AD diagnosis in the early stage and monitoring of the disease are of great importance. METHODS: In this review article, we have reviewed recent efforts for design, synthesis and evaluation of 99mTc labeled small molecule for AD imaging purposes. RESULTS: These small molecules include derivatives of Congo red, benzothiazole, benzofuran, benzoxazole, naphthalene, biphenyl, chalcone, flavone, aurone, stilbene, curcumin, dibenzylideneacetone, quinoxaline, etc. The different aspects of 99mTc-labeled small molecules including chemical structure, their affinity toward amyloid plaques, BBB permeation and in vivo/vitro stability will be discussed. CONCLUSION: The findings of this review confirm the importance of 99mTc-labeled small molecules for AD imaging. Future studies based on the pharmacophore of these designed compounds are needed for improvement of these molecules for clinical application.


Assuntos
Doença de Alzheimer/diagnóstico , Compostos de Organotecnécio/química , Bibliotecas de Moléculas Pequenas/química , Peptídeos beta-Amiloides/metabolismo , Barreira Hematoencefálica/metabolismo , Vermelho Congo/química , Curcumina/química , Humanos , Bibliotecas de Moléculas Pequenas/metabolismo , Tomografia Computadorizada de Emissão de Fóton Único
15.
Drug Discov Today ; 24(1): 315-324, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30278224

RESUMO

The presence of radiochemical impurities in a radiopharmaceutical contributes to an unnecessary radiation burden for the patients or to an undesirable high radioactivity background, which reduces the imaging contrast or therapeutic efficacy. Therefore, if the radiolabeling process results in unsatisfactory radiochemical purity, a purification step is unavoidable. A successful purification process requires a profound knowledge about the radiopharmaceuticals of interest ranging from structural features to susceptibility to different conditions. Most radiopharmaceutical purification methods are based on solid-phase extraction (SPE), high-performance liquid chromatography (HPLC), size exclusion chromatography (SEC), ion-exchange chromatography (IEC), and liquid-liquid extraction (LLE). Here, we discuss the basic and applied concepts of these purifications methods as well as their advantages and limitations.


Assuntos
Técnicas de Química Analítica/métodos , Compostos Radiofarmacêuticos/isolamento & purificação
16.
Curr Drug Metab ; 20(13): 1044-1052, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31721707

RESUMO

BACKGROUND: Solid Lipid Nanoparticles (SLNs) possess unique in vivo features such as high resistivity, bioavailability, and habitation at the target site. Coating nanoparticles with polymers such as chitosan greatly affects their pharmacokinetic behavior, stability, tissue uptake, and controlled drug delivery. The aim of this study was to prepare and evaluate the biodistribution of 99mTc-labeled SLNs and chitosan modified SLNs in mice. METHODS: 99mTc-oxine was prepared and utilized to radiolabel pre-papered SLNs or chitosan coated SLNs. After purification of radiolabeled SLNs (99mTc-SLNs) and radiolabeled chitosan-coated SLNs (99mTc-Chi-SLNs) using Amicon filter, they were injected into BALB/c mice to evaluate their biodistribution patterns. In addition, nanoparticles were characterized using Transmission Electron Microscopy (TEM), Fourier-transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), X-ray Powder Diffraction (XRD) and Dynamic Light Scattering (DLS). RESULTS: 99mTc-oxine with high radiochemical purity (RCP~100%) and stability (RCP > 97% at 24 h) was used to provide 99mTc-SLNs and 99mTc-Chi-SLNs with high initial RCP (100%). TEM image and DLS data suggest 99mTc- SLNs susceptibility to aggregation. To that end, the main portion of 99mTc-SLNs radioactivity accumulates in the liver and intestines, while 99mTc-Chi-SLNs sequesters in the liver, intestines and kidneys. The blood radioactivity of 99mTc-Chi-SLNs was higher than that of 99mTc-SLNs by 7.5, 3.17 and 3.5 folds at 1, 4 and 8 h post-injection. 99mTc- Chi-SLNs uptake in the kidneys in comparison with 99mTc-SLNs was higher by 37.48, 5.84 and 11 folds at 1, 4 and 8h. CONCLUSION: The chitosan layer on the surface of 99mTc-Chi-SLNs reduces lipophilicity in comparison with 99mTc- SLNs. Therefore, 99mTc-Chi-SLNs are less susceptible to aggregation, which leads to their lower liver uptake and higher kidney uptake and blood concentration.


Assuntos
Quitosana/farmacocinética , Lipídeos/farmacocinética , Nanopartículas/administração & dosagem , Oxiquinolina/farmacocinética , Compostos Radiofarmacêuticos/farmacocinética , Tecnécio/farmacocinética , Animais , Feminino , Camundongos Endogâmicos BALB C , Distribuição Tecidual
17.
Eur J Med Chem ; 175: 149-161, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31078865

RESUMO

Six novel 2-arylimidazo[2,1-b]benzothiazole (IBT) derivatives were synthesized as potential tridentate radiotracers for AD imaging purposes. Two of these ligands (6a,b) were successfully labeled with 99mTc radionuclide at high radiochemical purity using fac-[99mTc(CO)3(H2O)3]+ synthon. [99mTc]7a and [99mTc]7b were evaluated as single photon emission computed tomography (SPECT) imaging agents for Aß plaque in AD. [99mTc]7a and [99mTc]7b exhibited suitable affinity toward Aß aggregates with IC50 values of 33.2 and 102.5 nM, respectively. The IC50 value of these radiotracers depends on the length of the spacer (alkyl chain). In biodistribution study, these complexes showed good initial brain uptakes (0.78 and 0.86% ID/g at 2 min post-injection) and fast blood clearance. Autoradiography results confirmed that these small 99mTc complexes (Mw about 600 Da) can bind to Aß plaques in the brain sections of the rat AD model. Histopathological staining with Congo red approved the presence of Aß plaques in these brain sections.


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Benzotiazóis/metabolismo , Imidazóis/química , Compostos de Organotecnécio/metabolismo , Placa Amiloide/diagnóstico por imagem , Compostos Radiofarmacêuticos/metabolismo , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Doença de Alzheimer/metabolismo , Animais , Benzotiazóis/química , Benzotiazóis/farmacocinética , Barreira Hematoencefálica , Encéfalo/metabolismo , Modelos Animais de Doenças , Camundongos , Compostos de Organotecnécio/farmacocinética , Compostos Radiofarmacêuticos/farmacocinética , Ratos , Distribuição Tecidual
18.
Eur J Pharm Sci ; 114: 1-12, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29174988

RESUMO

Combined experimental and simulation investigations have provided molecular level insights into 5-iodo-2'-deoxyuridine (IUdR) loading behavior for the novel PEG/PCL/PEG polymersome-like carriers in mixed dichloromethane/N,N-dimethylformamide (DCM/DMF) solvent. As with the experiments, a novel approach was applied for layer by layer tailoring of polyethylene glycol (PEG) and polycaprolactone (PCL) as PEG/PCL/PEG copolymer on the surface of magnetite nanoparticles (MNPs) by click chemistry. Experimental results indicated that IUdR, as an anti-cancer drug, could be encapsulated up to 80% EE in this nanocarrier and could be in-vitro released up to 90% during 120h. Computational studies, on the other hand, provide molecular level insights into the optimal performance of the carrier in terms of drug "Dispersion" and "Diffusion" patterns in equimolar DCM/DMF solvent. Molecular dynamics simulations of the system in four distinct solvation scenarios including pure DCM, mixed DCM/DMF, pure DMF and water, have proven that while hydrophobic solvents give rise to better "dispersion" of drugs, hydrophilic solvents lead for drug molecules to penetrate into the carrier and improve "diffusion" properties. Optimal conditions for drug encapsulation, as also confirmed through experiments, was observed for mixed DCM/DMF solvent in terms of proper diffusion and well dispersion. While drug "aggregates" were observed in DCM, poorly stable drug molecules with lowered penetrations were observed in pure DMF. Proper release properties with IUdR molecules staying on the surface of the carrier was also observed in water. The interesting role of the star-linear architecture was further scrutinized through distinctions made through analysis of interactions between IUdR molecules with "inner" and "outer" PEG sections.


Assuntos
Dimetilformamida/síntese química , Cloreto de Metileno/síntese química , Simulação de Dinâmica Molecular , Poliésteres/síntese química , Polietilenoglicóis/síntese química , Solventes/síntese química , Difusão , Dimetilformamida/metabolismo , Portadores de Fármacos/síntese química , Portadores de Fármacos/metabolismo , Cloreto de Metileno/metabolismo , Conformação Molecular , Poliésteres/metabolismo , Polietilenoglicóis/metabolismo , Solubilidade , Solventes/metabolismo
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