Radiolabeling and in vitro evaluation of a new 5-fluorouracil derivative with cell culture studies.

The clinical impact and accessibility of 99m Tc tracers for cancer diagnosis would be greatly enhanced by the availability of a new, simple, and easy labeling process and radiopharmaceuticals. 5-Fluorouracil is an antitumor drug, which has played an important role for the treatment of breast carcinoma. In the present study, a new derivative of 5-Fluorouracil was synthesized as (1-[{1'-(1''-deoxy-2'',3'':4'',5''-di-O-isopropylidene-ß-D-fructopyranose-1''-yl)-1'H-1',2', 3'-triazol-4'-yl}methyl]-5-fluorouracil) (E) and radiolabeled with 99m Tc. It was analyzed by radio thin layer chromatography for quality control and stability. The radiolabeled complex was subjected to in vitro cell-binding studies to determine healthy and cancer cell affinity using HaCaT and MCF-7 cells, respectively. In addition, in vitro cytotoxicity studies of compound E were performed with HaCaT and MCF-5 cells. The radiochemical purity of the [99m Tc]TcE was found to be higher than 90% at room temperature up to 6 hours. The radiolabeled complex showed higher specific binding to MCF-7 cells than HaCaT cells. IC50 values of E were found 31.5 ± 3.4 µM and 20.7 ± 2.77 µM for MCF-7 and HaCaT cells, respectively. The results demonstrated the potential of a new radiolabeled E with 99m Tc has selective for breast cancer cells.

Gamma scintigraphy and biodistribution of (99m)Tc-cefotaxime sodium in preclinical models of bacterial infection and sterile inflammation.

(99m)Tc-cefotaxime sodium ((99m)Tc-CEF) was developed and standardized under varying conditions of reducing and antioxidant agent concentration, pH, radioactivity dose, and reducing agent type. Labeling studies were performed by changing the selected parameters one by one, and optimum labeling conditions were determined. After observing the conditions for maximum labeling efficiency and stability, lyophilized freeze dry kits were prepared accordingly. Simple method for radiolabeling of CEF with (99m)Tc has been developed and standardized. Labeling efficiency of (99m)Tc-CEF was assessed by both radio thin-layer chromatography and radio high-performance liquid chromatography and found higher than 90%. The labeled compound was found to be stable in saline and human serum up to 24 h. Two different freeze dry kits were developed and evaluated. Based on the data obtained from this study, both products were stable for 6 months with high labeling efficiency. The prepared cold kit was found sterile and pyrogen free. The bacterial infection and sterile inflammation imaging capacity of (99m)Tc-CEF was evaluated. Based on the in vivo studies, (99m)Tc-CEF has higher uptake in infected and inflamed thigh muscle than healthy thigh muscle.

Comparative permeability studies with radioactive and nonradioactive risedronate sodium from self-microemulsifying drug delivery system and solution.

The purpose of this work is to prepare a self-microemulsifying drug delivery system (SMEDDS) for risedronate sodium (RSD) and to compare the permeability with RSD solution. The solubility of RSD was determined in different vehicles. Phase diagrams were constructed to determine the optimum concentration of oil, surfactant, and cosurfactant. RSD SMEDDS was prepared by using a mixture of soybean oil, cremophor EL, span 80, and transcutol (2.02:7.72:23.27:61.74, w/w, respectively). The prepared RSD SMEDDS was characterized by droplet size value. In vitro Caco-2 cell permeability studies were performed for SMEDDS and solution of radioactive ((99 m)Tc-labeled RSD) and nonradioactive RSD. The experimental results indicated that RSD SMEDDS has good stability and its droplet size is between 216.68 ± 3.79 and 225.26 ± 7.65 during stability time. In addition, RSD SMEDDS has higher permeability value than the RSD solution for both radioactive and nonradioactive experiments. The results illustrated the potential use of SMEDDS for delivery of poorly absorbed RSD.

(99m) Tc-Doxycycline hyclate: a new radiolabeled antibiotic for bacterial infection imaging.

Radiolabeled antibiotics are promising radiopharmaceuticals for the precise diagnosis and detection of infectious lesions. Doxycycline Hyclate (DOX) was chosen to investigate new (99m) Tc-labeled antibacterial agent. Ready to use freeze dry kits were formulated with optimum labeling conditions. Human serum stability, sterility, and pyrogenicity of kits were estimated, and gamma scintigraphy, in vivo biodistribution, and histopathological studies with bacterial infected rats were performed. DOX were successfully labeled by (99m) Tc with high radiochemical purity, and the labeled compound was stable in human serum. Kits were sterile, pyrogen-free, and stable up to 6 months. Static images depicted rapid distribution throughout the body and high uptake in bacterial infected thigh muscle. The uptake ratios of radiopharmaceuticals in infected thigh muscle were found above 2 up to 5 h. Five hours after injection, the rats were sacrificed, and biodistribution was determined. Samples of bacterial infected muscle, healthy muscle, blood, liver, spleen, lung, kidney, stomach, intestine, urine and heart were weighed, and the radioactivity was measured by using a gamma counter. The %ID/g of (99m) Tc-DOX was found 0.23 ± 0.06 for infected thigh muscle. According to the imaging, biodistribution, and histopathological studies, the promising characteristics of (99m) Tc-DOX make the new radiopharmaceutical valuable to examine for future studies.

Radiolabeling, Quality Control, and Cell Binding Studies of New 99mTc-Labeled Bisphosphonates: 99mTc-Ibandronate Sodium.

Objectives: Early detection of bone cancer is critical for treating symptoms, minimizing pain, and increasing overall quality of life. It is critical to develop novel radiopharmaceuticals with high labeling efficiency and stability for the diagnosis of bone cancer. This research aims to design a novel radiopharmaceutical that may be used to diagnose bone cancer. Materials and Methods: In this study, ibandronate sodium (IBD), a bisphosphonate analog, was radiolabeled with technetium-99m [99mTc] and quality control tests on the newly developed radiopharmaceutical ([99mTc]Tc-IBD) were performed using radioactive thin layer chromatography. After that, the incorporation of [99mTc]Tc-IBD into hydroxyapatite (HA) crystals and a human bone osteosarcoma cell line (U2OS) was tested. Results: According to the results obtained, optimal radiolabeling procedure was obtained for [99mTc]Tc-IBD with 200 µg.mL-1 IBD, 20 µg stannous chloride, and 99mTc with 37 MBq radioactivity. The reaction mixture was adjusted to pH 5.5 and incubated at room temperature for 15 min. The radiochemical purity of [99mTc]Tc-IBD was found to be greater than 95% at room temperature for up to 6 h. Additionally, chromatography analysis showed >95% [99mTc]Tc-IBD complex formation with promising stability for up to 24 h in saline and up to 2 h in cell medium. The percentage binding of IBD to HA was 83.70 ± 3.67 and the logP of [99mTc]Tc-IBD was -1.1014. The radiolabeled complex exhibited a higher rate of cell incorporation to U2OS cells compared to Reduced/Hydrolyzed 99mTcO4 -. Conclusion: The newly produced radiopharmaceutical is very promising according to the results of in vitro cell culture, HA binding, and quality studies, and will be a step forward for further studies in nuclear medicine for bone cancer diagnostics.

The effect of radiolabeled nanostructured lipid carrier systems containing imatinib mesylate on NIH-3T3 and CRL-1739 cells.

The aim of current study is to develop new nanostructured lipid carrier systems (NLCSs) containing imatinib mesylate (IMT) and evaluate their targeting efficiency on NIH-3T3 as fibroblast cells and CRL-1739 as gastric adenocarcinoma cells with radiolabeled formulations. Three formulations (F1-IMT, F2-IMT and F3-IMT) were prepared and radiolabeled with 1 mCi/0.1 mL of [99mTc]Tc. The effect of reducing and antioxidant agents on radiolabeling process was evaluated and radiochemical purity of formulations was performed by radio thin-layer radiochromatography (RTLC). The results demonstrated that the radiochemical purity was found to be above 90% for [99mTc]Tc-F1-IMT and [99mTc]Tc-F2-IMT, while radiochemical purity of [99mTc]Tc-F3-IMT was found to be 85.61 ± 2.24%. Also, [99mTc]Tc-F1-IMT and [99mTc]Tc-F2-IMT have better stability in cell medium and saline than [99mTc]Tc-F3-IMT. Targeting efficiency of [99mTc]Tc-F1-IMT and [99mTc]Tc-F2-IMT comparatively evaluated by cell binding studies with [99mTc]NaTcO4 on NIH-3T3 and CRL-1739 cells. The cell binding capacity and targeting/non-targeting cell uptake ratio of these two formulations was found to be higher than [99mTc]NaTcO4 in CRL-1739. It is thought that the knowledge achieved in this study would contribute to using [99mTc]Tc-F1-IMT and [99mTc]Tc F2-IMT as an diagnosis and treatment agents.

Tc-99m Radiolabeled Alendronate Sodium Microemulsion: Characterization and Permeability Studies Across Caco-2 Cells.

BACKGROUND: Alendronate sodium (ALD) is used orally but it is poorly absorbed from the gastrointestinal (GI) tract. For this reason, microemulsion system was chosen to evaluate ALD from the GI tract after oral delivery. OBJECTIVE: This study was aimed to prepare water-in-oil (w/o) microemulsion formulation of ALD and evaluate the permeability of ALD microemulsion from Caco-2 cell lines with radioactive and nonradioactive studies. METHOD: The ALD microemulsion was developed by using pseudo-ternary phase diagram and composed of Soybean oil, Colliphor EL, Tween 80, Transcutol and distilled water. The prepared ALD microemulsion was characterized by physical appearance, droplet size, viscosity, pH, electrical conductivity and refractive index. The stability of the formulation was investigated for 6 months at 25±2°C/60±5% of relative humidity (RH) as well as at 40±2°C/75±5% RH. After that 1 mg of ALD was radiolabeled with 99mTc and added to microemulsion. The permeability studies were performed with both 99mTc-ALD microemulsion and ALD microemulsion. RESULTS: The experimental results suggested that ALD microemulsion presented adequate stability with droplet size varying from 37.8±0.9 to 39.9±1.2 nm during incubation time. In addition, ALD microemulsion was radiolabeled with high labeling efficiency (>95%). In a non-radioactive study, ALD permeability was found to be 45 µg.mL-1 and microemulsion has high permeability percentage when compared to another study. CONCLUSION: The novel w/o microemulsion formulation has been developed for oral delivery of ALD. Based on the results, permeability of ALD could be significantly improved by the microemulsion formulation. In addition, 99mTc-ALD microemulsion in capsule can be used for bone disease treatment and diagnosis.

Development and Evaluation of Liquid and Solid Lipid Based Drug Delivery Systems Containing Technetium-99m-Radiolabeled Alendronate Sodium.

OBJECTIVE: The purpose of this study was to develop lipid-water based drug delivery system of Alendronate Sodium (ALD) in liquid and solid form obtained by using spray drying method and compare these two forms with radioactive cell culture studies. METHODS: This study included the development of liquid and solid form obtained by spray drying method, radiolabelling of ALD with 99mTc, preparation of formulations containing 99mTc -ALD and evaluation of their permeability with Caco-2 cell. The liquid formulations have been developed by using various surfactants, co-surfactants, oil and water phases. Physicochemical characterizations like droplet size, polydispersity index (PDI) and zeta potential measurements and short term stability studies were investigated. RESULTS: According to the measurement results, two oil in water formulations (F1-L and F2-L) were selected and spray dried with Buchi mini spray dryer apparatus to provide solid formulations (F1-S and F2-S). ALD was labeled with 99mTc and added to formulations. The effect of experimental conditions on radiolabeling efficiency of ALD and stability of all formulations containing 99mTc-ALD were investigated through Radio Thin Layer Chromatography (RTLC). It was observed that the labeling efficiency of ALD was greater than 90% and all formulations were found to be stable up to 6 h at room temperature. Permeability of radiolabeled ALD from all formulations was performed by using Caco-2 cells. According to the cell culture studies, permeability from spray dried formulations of ALD was found higher than liquid formulations. CONCLUSION: As a conclusion, spray dried formulations could be a promising drug delivery system for enhancing the permeability of ALD. Furthermore, this study is a good example of the use of radiolabeled compounds in drug development.

In loco retention effect of magnetic core mesoporous silica nanoparticles doped with trastuzumab as intralesional nanodrug for breast cancer.

Breast cancer is women's most common type of cancer, with a global rate of over 522,000 deaths per year. One of the main problems related to breast cancer relies in the early detection, as the specialized treatment. In this direction was developed, characterized and tested in vivo a smart delivery system, based on radiolabelled magnetic core mesoporous silica doped with trastuzumab as intralesional nanodrug for breast cancer imaging and possible therapy. The results showed that nanoparticles had a size of 58.9 ± 8.1 nm, with specific surface area of 872 m2/g and pore volume of 0.85 cm3/g with a pore diameter of 3.15 nm. The magnetic core mesoporous silica was efficiently labelled with 99mTc (97.5% ±0.8) and doped >98%. The cytotoxicity assay, demonstrated they are safe to use. The data were corroborated with the IC50 result of: 829.6 µg ± 43.2. The biodistribution showed an uptake by the tumour of 7.5% (systemic via) and 97.37% (intralesional) with less than 3% of these nanoparticles absorbed by healthy tissues. In a period 6-h post-injection, no barrier delimited by the tumour was crossed, corroborating the use as intralesional nanodrug.

Preparation of 99mTc-isosulfan blue for lymph node localization in rats 99mTc-isosulfan blue for lymph node localization.

The sentinel lymph node (SLN) is defined as the first regional lymph node to receive lymphatic drainage from a malignant tumor. Therefore, this node is a "sentinel" for second metastatic lymph node stations and for labeling regional tumor spread. For SLN detection, many surgeons preferred a combination of a preoperative injection of radiolabeled colloid and the intraoperative injection of blue dye. Under this combination protocol, nodes are considered to be "sentinel nodes" if they are radioactive and blue. The aim of this study is to develop a new single agent that combines both detection methods. For this purpose Isosulfan Blue (ISB) was radiolabeled by 99mTc with high labeling yield and stability. In vivo gamma scintigraphy studies were performed with rats. According to the scintigraphic studies, 99mTc-ISB shows rapid and high accumulation in both axillary (ALN) and popliteal lymph node (PLN). After the imaging study, extremity was opened and nodes were scanned for the radioactivity. According to performed study the lymph nodes were clearly seen to become blue and carried compound was sufficient to allow identification with a gamma probe. In conclusion, 99mTc-ISB has the potential to facilitate lymphatic mapping and subsequent sentinel node biopsy for solid malignancies such as breast cancer and melanoma.

Effect of microemulsion formulation on biodistribution of 99mTc-Aprotinin in acute pancreatitis models induced rats.

BACKGROUND: Aprotinin is a monomeric globular polypeptide, which derived from bovine lung tissue and theoretically attractive molecule in ameliorating the effects of acute pancreatitis. Acute pancreatitis is an inflammatory condition of the pancreas that is painful and at times deadly. Over the following two decades Aprotinin therapeutic potential on pancreatitis is proven experimentally, its clinical therapeutic success is limited due to low targeting to pancreas. OBJECTIVE: The aim of this study was to evaluate the biodistribution of Technetium-99m (99mTc)-Aprotinin solution (99mTc-Aprotinin-S) and 99mTc-Aprotinin loaded microemulsion, which was prepared for the aim of treatment for acute pancreatitis. METHOD: Aprotinin was radiolabeled with 99mTc. Radiochemical purity was determined with radioactive thin layer chromatography studies. 99mTc-Aprotinin-S and 99mTc-Aprotinin loaded microemulsion (99mTc-Aprotinin-M) was administered to acute edematous, severe necrotizing pancreatitis and air pouch model induced rats. Tissue distribution of Aprotinin was investigated with gamma scintigraphy and biodistribution studies. RESULTS: Aprotinin was radiolabeled by 99mTc with high radiochemical purity (95.430 ± 0.946%). The complex was found to be stable at room temperature up to 6 h. Animal studies have shown that similar to that of other small proteins Aprotinin is accumulated primarily in the kidney. The scintigraphy and biodistribution studies showed that, while i.v. administration of 99mTc-Aprotinin-S distributed mostly in kidneys and bladder, 99mTc-Aprotinin-M, with droplet size of 64.550 ± 3.217 nm, has high uptake in liver, spleen and pancreas. CONCLUSION: This might be concluding that microemulsions may be suggested as promising formulations for selectively targeting Aprotinin to pancreas inflammation.

Assessment of Aprotinin Loaded Microemulsion Formulations for Parenteral Drug Delivery: Preparation, Characterization, in vitro Release and Cytotoxicity Studies.

The object of the current study was to prepare novel microemulsion formulations of aprotinin for parenteral delivery and to compare in vitro characteristics and release behaviour of different Technetium-99m ((99m)Tc)-Aprotinin loaded microemulsion formulations. In addition, cytotoxicity of microemulsion formulation was evaluated with cell culture studies on human immortalized pancreatic duct epithelial-like cells. For this aim, firstly, pseudo-ternary phase diagrams were plotted to detect the formulation region and optimal microemulsions were characterized for their thermodynamic stability, conductivity, particle size, zeta potential, viscosity, pH and in vitro release properties. For in vitro release studies aprotinin was labelled with (99m)Tc and labelling efficiency, radiochemical purity and stability of the radiolabeled complex were determined by several chromatography techniques. Radiolabeling efficiency of (99m)Tc-Aprotinin was found over than 90% without any significant changes up to 6 hours after labelling at room temperature. After that, in vitro release studies of (99m)Tc-Aprotinin loaded microemulsions were performed with two different methods; dissolution from diffusion cells and dialysis bags. Both methods showed that release rate of (99m)Tc- Aprotinin from microemulsion could be controlled by microemulsion formulations. Drug release from the optimized microemulsion formulations was found lower compared to drug solution at the end of six hours. According to stability studies, the optimized formulation was found to be stable over a period of 12 months. Also, human immortalized pancreatic duct epithelial-like cells were used to evaluate the cytotoxicity of optimum formulation. Developed microemulsion did not reveal cytotoxicity. In conclusion the present study indicated that the M1-APT microemulsion is appropriate for intravenous application of aprotinin.

Aprotinin revisited: formulation, characterization, biodistribution and therapeutic potential of new aprotinin microemulsion in acute pancreatitis.

The aim of this study was to develop aprotinin-loaded microemulsion (MA) for intravenous administration and evaluate the biodistribution and therapeutic potential of developed formulation in acute pancreatitis models in rats. Phase diagrams were constructed to identify microemulsion region and the optimal microemulsion was evaluated for physicochemical properties and treatment effect in rats, and comparisons made with the solution of aprotinin (SA). To evaluate the biodistribution of the drug by gamma scintigraphy aprotinin was radiolabeled with (99m)Tc radionuclide. Mild and severe acute pancreatitis was induced in rats by subcutaneous injections of cerulein and introductal infusion of 3% sodium taurocholate into the bile-pancreatic duct, respectively. In addition, serum amylase and pancreatic tissue myeloperoxidase activities were measured to evaluate the pancreatic damage. According to gamma scintigraphy and biodistribution studies, accumulation times and distribution of (99m)Tc-MA and SA were different. While MA was highly uptake by reticuloendothelial system, SA was mostly excreted by kidneys and bladder. Compared with the mild acute pancreatitis group, treatment with MA significantly decreased the serum amylase activity and pancreas myeloperoxidase activity. Furthermore, the protease inhibitor molecule aprotinin has therapeutic potential in acute pancreatitis. Finally, MA may be suggested as a promising alternative for treatment of acute pancreatitis.

Determination of in vivo behavior of mitomycin C-loaded o/w soybean oil microemulsion and mitomycin C solution via gamma camera imaging.

In this study, a microemulsion system was evaluated for delivery of mitomycin C (MMC). To track the distribution of the formulated drug after intravenous administration, radiochemical labeling and gamma scintigraphy imaging were used. The aim was to evaluate a microemulsion system for intravenous delivery of MMC and to compare its in vivo behavior with that of the MMC solution. For microemulsion formulation, soybean oil was used as the oil phase. Lecithin and Tween 80 were surfactants and ethanol was the cosurfactant. To understand the whole body localization of MMC-loaded microemulsion, MMC was labeled with radioactive technetium and gamma scintigraphy was applied for visualization of drug distribution. Radioactivity in the bladder 30 minutes after injection of the MMC solution was observed, according to static gamma camera images. This shows that urinary excretion of the latter starts very soon. On the other hand, no radioactivity appeared in the urinary bladder during the 90 minutes following the administration of MMC-loaded microemulsion. The unabated radioactivity in the liver during the experiment shows that the localization of microemulsion formulation in the liver is stable. In the light of the foregoing, it is suggested that this microemulsion formulation may be an appropriate carrier system for anticancer agents by intravenous delivery in hepatic cancer chemotherapy.

The rabbit biodistribution of a therapeutic dose of zoledronic acid labeled with Tc-99m.

The aim of the present study was to label a therapeutic dose of zoledronic acid (ZOL) with Tc-99m, evaluate its in vitro stability and compare its biodistribution to (99m)Tc-methylene biphosphonate ((99m)Tc-MDP) in normal rabbits. Preparation of 0.50 mg of (99m)Tc-ZOL was carried out by the reduction of (99m)Tc-pertechnetate in the presence of stannous chloride. The radiolabeling efficiency was found to be greater than 99%. The labeled complex was stable at least up to 6 h at room temperature determined by paper chromatography. (99m)Tc-ZOL and (99m)Tc-MDP were administered intravenously to the rabbits for scintigraphic studies. Between (99m)Tc-ZOL and (99m)Tc-MDP, there were no significant differences in the ratios of femur/BG and lumbar vertebrae/BG, whereas epiphysis/BG and the kidney/BG ratios of (99m)Tc-MDP were higher than (99m)Tc-ZOL at the static studies.

The absorption of (99m)Tc-alendronate given by rectal route in rabbits.

Alendronate sodium (ALD) is a bisphosphonate medication used in the treatment and prevention of osteoporosis. Absorption of ALD as oral formulation is very poor (0.5%-1%). Its bioavailability can decrease with food effect. It has some gastrointestinal adverse effects such as gastritis, gastric ulcer, and esophagitis. The aim of this study was to develop a rectal formulation of ALD as an alternative to oral route and to investigate the absorption of it by using gamma scintigraphy. For this reason, ALD was labeled with Technetium-99m ((99m)Tc) by direct method. The radiochemical characterization of the (99m)Tc-ALD was carried out by paper chromatography, thin layer chromatography, and electrophoresis methods. The labeling efficiency of (99m)Tc-ALD was found 99% without significant changes until 6 h postlabeling at room temperature. The rectal suppositories containing (99m)Tc-ALD were prepared by fusion method using polyethylene glycol (PEG) 1500. The (99m)Tc-labeled ALD suppositories were administrated to rabbits by rectal route. Serial scintigrams over all bodies of the rabbits were obtained at different time intervals using a gamma camera. We found that the rectal absorption of (99m)Tc-ALD from suppository formulation was possible. According to our results, this formulation of ALD can be suggested for the therapy of osteoporosis as an alternative route.