99mTc-exendin-4: Radiolabeling and quality control studies of glucagon-like peptide analog

Aim: Exendin-4 is a type 2 diabetes antidiabetic drug that is a peptide agonist of the glucagon-like peptide 1 receptor (GLP-1R). Up to date, different exendin-4 compounds have been radiolabeled with many radioisotopes such as 68Ga, 18F, 64Cu and 99mTc for various purposes like study of over expression of GLP-1R in insulinoma. The purpose of this study is to radiolabel exendin-4 with 99mTc under appropriate conditions. Methods: In this study, exendin-4 was labeled with 99mTc, and quality control tests of 99mTc-exendin-4 were done using ascending radioactive thin layer chromatography (RTLC). Also, the effects of important parameters such as the amount of reducing agent, pH value, incubation time, and radiation dose on the labeling efficiency were investigated. Then, the stability of 99mTc-exendin-4 was assessed. Results: According to the results, 99mTc-exendin-4 was prepared with over 95 percent labeling efficiency by a novel, easy, and quick direct method with 30-min incubation time at pH 6.6. To achieve the best radiolabeling condition; 10 µg of exendin-4, 50 µg of stannous chloride (reducing agent) and 37 MBq 99mTc was used. The RTLC studies indicated that 99mTc-exendin-4 is stable up to 6 h in room temperature. Conclusion: The obtained results demonstrated that radiolabeled exendin-4 may be a promising agent for GLP-1R imaging studies. Further studies are in progress in order to evaluate receptor binding capacity and biodistribution of the complex in experimental animals

Computational Study of Radiopharmaceuticals

Radiopharmaceuticals contain radionuclides and pharmaceuticals. Research on radiopharmaceuticals has been increasing in recent years by increasing the importance of early diagnosis in diseases. It is generally accepted that investigation and development of new radiopharmaceuticals are time and resource consuming. Computational methods have provided exciting contributions to pharmaceutical research and development. The need for designing new radiopharmaceutical drugs enhances the importance of computational programs. At this point, the structure, chemical, physical and physicochemical properties of molecules should be predicted/evaluated by using computational methods. While these methods obtain useful estimates, they make it easier for researchers and clinicians to make the right choices. Also, by providing accurate and effective results, they contribute to reduce the cost of research and can be used to simulate complex biochemical situations before research helping us to avoid harmful effects of drugs. In this study, authors emphasis about radiopharmaceuticals and the computational tools related to the development of new radiopharmaceuticals

The Effect of Welding Positions on the Weldability of X20CrMoV11-1 Steels

I n the study, mechanical properties of martensitic steel X20CrMoV11-1 was investigated after being welded using Tungsten Inert Gas GTAW welding method at different weld positions PC and PJ-EN 6947 . The X20CrMoV11-1 steels have been widely used in thermal power plant applications in combustion chambers and other high-temperature parts. These materials experience extremely high internal pressure at the service conditions. WCrMoV12 Si was used as the filler metal in the welding. The GTAW welding process was conducted in a controlled manner and all the parameters used during the process was monitored. The post welding heat treatment was applied in order to eliminate the variations in the hardness of the welded materials. The samples were characterized using tensile, bending, hardness, and notch impact tests. Macro photographs were taken from the samples to observe the transition areas. The results indicated that the mechanical properties obtained from the samples welded in PC position were higher than those obtained from PJ position

Pre-clinic study of radiopharmaceutical for Covid-19 inactivation: Dose distribution with Monte Carlo Simulation

Monte Carlo simulation method and Nuclear Medicine MIRD method were used to evaluate the effect of ra-diopharmaceuticals on Covid-19 disease. The mean absorbed organ dose in the target organ and gamma radi-ation emitter attenuation properties such as linear attenuation coefficients, energy absorption build-up factors (EABF), exposure build-up factors (EBF), and relative dose distributions (RDD) were examined. The results showed that radiopharmaceuticals containing gamma radiation emitters which are densely ionizing charged particles induced membrane damage and produced protein damage

Microemulsion Drug Delivery Systems for Radiopharmacy Studies

WOS: 000395756400049Microemulsions have been used increasingly for last year's because of ideal properties like favorable drug delivery, ease of preparation and physical stability. They have been improved the solubility and efficacy of the drug and reduce the side effects. Use of radiolabeled microemulsions plays an alternative role in drug delivery systems by investigating the formation, stability and application of microemulsions in radiopharmacy. Gama scintigraphic method is well recognized for developing and detecting the biodistribution of newly developed drugs or formulation. This review will focus on how radionuclides are able to play role with characterization studies of microemulsion drug delivery systems

The effects of obstructive jaundice on the brain: An experimental study

The study aims to evaluate the alterations in the brain due to oxidative stress and lipid peroxidation resulting from obstructive jaundice. Forty-one Wistar albino rats were used in this study. Simple laparotomy was performed in the sham group (n = 5). In the remaining 36 rats, the common bile duct (CBD) was found and ligated. They were divided into six groups. Group I, Group II, and Group III were sacrificed at the 3rd, 7th, and 14th day of ligation, respectively. In Group Id, Group IId, and Group IIId ligated bile ducts were decompressed at the 3rd, 7th, and 14th day, respectively. One week after decompression these rats were also sacrificed and samples were taken. After the CBD ligation, serum levels of bilirubin and malondialdehyde were found to be increased progressively in parallel to the ligation time of the CBD. After decompression these values decreased. In electron microscopy evaluation, the damage was found to be irreversible depending on the length of the obstruction period. In Group II, the damage was mostly reversible after the internal drainage period of 7 days. However in Group III, the tissue damage was found to be irreversible despite the decreased values of oxidative stress and bilirubin. Ultrastructural changes in brain tissue including damage in the glial cells and neurons, were found to be irreversible if the CBD ligation period was >7 days and did not regress even after decompression. It is unreliable to trace these changes using blood levels of bilirubin and free radicals. Therefore, timing is extremely critical for medical therapies and drainage

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

WOS: 000444275000004PubMed ID: 29807525Objective: 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 Tc-99m, preparation of formulations containing Tc-99m-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 (F -S and F2-S). ALD was labeled with Tc-99m and added to formulations. The effect of experimental conditions on radiolabeling efficiency of ALD and stability of all formulations containing Tc-99m-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 radio-labeled compounds in drug development