Radio Pharmacy - Assignment Example

Radio Pharmacy Name University Author Note Radio Pharmacy Question 1 Radiopharmaceuticals are intended for human administration and therefore must undergo quality control procedures. Quality control of pharmaceuticals involves various specified tests and measurements to ensure purity, biologic safety, identification of the product and guarantee the efficacy of the drugs. Quality control measures that are applied to nonradioactive pharmaceuticals are also applicable to radiopharmaceuticals. Often, its manufacturers carry out quality control tests from the beginning of production to the time the final product is ready. The nuclear medicine department also conducts quality control tests before using the drugs to ensure that they are of required quality. Quality control tests are classified into two: physiochemical tests and biological tests. Physiochemical tests are conducted to determine the level of radiochemical and radionuclidic impurities. They are also used to determine the PH, physical state of the sample, osmolality, and strength of the drug. Biological tests are done to establish the level of toxins and sterility of the material (Saha, 2004). The determination of the integrity and purity of Tc- 99m Sestamibi, different vitro physicochemical tests are performed. The physical characteristics of Tc- 99m Sestamibi is established during quality control tests. The colour and appearance of the drug are determined first. The heat sustainability of the drug is also determined. After ascertaining the physical properties of the drug, it is then checked for any chemical impurities. There are three types of radiochemical impurities that are determined for Tc- 99m Sestamibi: free technetium 99mTc pertechnetate (99mTcO4 - ), hydrolyzed-reduced 99mTc (insoluble 99mTc dioxide and 99mTc tin colloid), and bound 99mTc to a particular ligand. A chromatography system can be used to determine the impurities. The system consists of a stationary phase and a solvent. Chromatography is a procedure that separates components of a solution. Thin layer chromatography (TLC) is used to determine the purity of radio chemicals in a nuclear machine. This method is also used in radio pharmacy to determine the purity of drugs. A radioactive sample that is spotted onto the absorbent migrates with different velocities depending on the distribution of contents between the solvent and absorbent. This leads to the separation of impurities (Saha, 2004). Separation of impurities is based on the principles of electrostatic forces (adsorption), ion exchange (charge) and solubility. The movement of the solvent determines whether the TLC is ascending or descending. However, in nuclear medicine laboratories, ascending TLC is highly preferred. TLC offers fast and safe separation of properties. The radio pharmacists can separate impurities from the drugs and hence come up with most efficient radiopharmaceuticals. Question 2. TC-99m Sestamibi is a radioisotope for a radiopharmaceutical known as Cardiolite. This radiopharmaceutical is used in myocardial perfusion imaging. This procedure is an imaging test that is not invasive. The test is used to show the flow or perfusion of blood in heart muscles. The test can show areas of the heart that are not receiving enough blood flow and how well the heart is pumping blood. Myocardial perfusion imaging is carried out by specific radiopharmaceuticals. These radiopharmaceuticals have physiological and physical properties that make them best fit for use in the test. Tc- 99m Sestamibi and Tc-99m Teboroxime are the radiopharmaceuticals that are used in this process. The photon energy that is contained by Tc- 99m Sestamibi is 140KeV. The radiopharmaceutical has a half life of 6 hours. This implies that the atoms of the radiopharmaceutical decay after 6 hours to decay and do not have a lasting effect on the body of the patient and other biological functions. The excretion o Tc- 99m Sestamibi is hepatobiliary. This excretion method allows for complete excretion of all the chemical contents of the radiopharmaceutical after completion of the process. The target organs of Tc- 99m Sestamibi includes the colony, the kidneys, bladder, and the gallbladder. Tc- 99m Sestamibi is used for the parathyroid scan. For adults, a dose of 20mCi IV is administered. The drug is administered 15 minutes before an early scan and 2 hours to a delayed scan. Tc- 99m Sestamibi is a small molecule. It is a coordination compound that consists of radioisotope technetium-99m. It is bound to sesta 6 MIBI ligands. The drug is taken by the breast tissue, myocardium and or the parathyroid. Tc- 99m Sestamibi is an injectable that is indicated for the evaluation of myocardial function and coming up with information for use in making patient management decisions. The drug is also indicated for procedures diagnosing coronary artery disease. It localizes myocardial ischemia and infarction in the diagnosis of diseases that affect the coronary artery. High first pass myocardial extraction A Linear relationship between absorption and flow is a significant factor for radiopharmaceuticals that are utilized for myocardial perfusion imaging. The structure of drug must allow a balanced between the absorption and flow of the drug. A linear relationship in this context implies that the uptake and flow of the drug are at the bar. The structure of Tc- 99m Sestamibi allows it flow smoothly and be absorbed fast into the bloodstream. The figure below is the structure of Tc- 99m Sestamibi radiopharmaceutical. Figure 1. Structure of Tc- 99m Sestamibi The physiologic characteristics of new technetium-99m-named myocardial imaging specialists (Tc-99m sestamibi, an isonitriles; and Tc-99m teboroxime, a boronic corrosive adduct of technetium dioxime) are talked about and contrasted with thallium-201 (Tl-201). Concentrates with confined hearts, subcellular parts and cell societies show that Tc-99m sestamibi, Tc-99m teboroxime, and Tl-201 don't share regular transport or sequestration components. In spite of the fact that pinnacle Tc-99m sestamibi myocardial extraction after some time is a significant portion of that of Tl-201 at proportionate coronary blood streams, the measure of Tc-99m sestamibi that remaining parts in the heart is like that of Tl-201 in light of its higher maintenance proficiency. Support levels and proficiency for Tc-99m sestamibi additionally brings about insignificant redistribution. Interestingly, Tc-99m teboroxime myocardial extraction is more than the standard of Tl-201. However, the maintenance is not very productive, bringing about moderately fast washout attributes which may rapidly bring about tracer redistribution (Saha, 2004). Amid reperfusion after a no-stream period, the extraction of Tc-99m sestamibi and maintenance increment, however for Tc-99m teboroxime and Tl-201 these qualities diminish often. All tracers indicate satisfactory flow attributes for perfusion imaging, and contrasts in flow and support should prompt the improvement of modern clinical conventions. Question 3 Monoclonal antibodies are those antibodies that are generated in vitro through the multiplication of single hybrid cells and are obtained from the process of cloning specific cells from a common source. Monoclonal antibodies are pure and specific. Conventional monoclonal production method was carried out by injecting the test animal with a specific antigen. After a few days, blood is drawn from the test animal, and the antibodies are extracted from the blood. This process failed regarding both quality and quantity. Tit produced impure and fewer antibodies. The failure of this process led to the adoption of cloning technique as an option for producing antibodies in vitro. The cloning technique involves selection of tumor cells for their ability to multiply intensively. At the start of the production, the test animal is injected with an antigen that stimulated the production of antibodies. The cells that produce antigens are identified and extracted from the spleen of the animal and fused with myeloma cells that are earlier extracted from the animal and cultured in vitro. The process produces a hybrid cell that is observed for the desired antibody and later subjected to growth in culture to produce high quality of monoclonal antibodies. The sequence of obtaining pure monoclonal antibodies is centrifugation, filtration and then ion exchange chromatography is performed. After purification, the purity level of the monoclonal antibody is checked using gel electrophoresis (Saha, 2004). 3b CEA-Scan is an example of monoclonal antibody radiopharmaceutical. The radioisotope for this radiopharmaceutical is Tc-99m Arcitumomab. Tc-99m Arcitumomab is a monoclonal antibody that is used for colorectal cancer. CEA-Scan is a fragment antigen binding that is increased in various carcinomas especially the gastrointestinal tract. This monoclonal antibody is used to mark cancer tumors in the colon and the rectum. Arcitumomab enhances the determination of pre-operative resectability. Arcitumomab has carcinoembryonic antigen that is over expressed in 95% of colorectal cancers. The monoclonal antibody accumulates colorectal cancer tumors together with the radioisotope that emits photons. High-resolution images that show the locality, remission and metastases of a tumor are obtained via single photon emission computed tomography SPECT. 3c CEA-Scan has a short biological life of 13plus/minus 4 hours. It causes rapid clearance of blood and has a minimal liver metabolism. Comparison with the CT scan indicates that CEA-Scan increases the detection in patients who have resectable diseases by 40 percent. (66vs 47%). It also provides an increase of 143% in detections of non-resectable patients (47 vs. 19%). Additionally, the monoclonal antibody decreases false negative rate by 0% and gives a positive predictive value of 97% (Saha, 2004). Limitations It does not cover differential diagnosis of suspected colorectal carcinoma. It does not offer to screen for colorectal carcinoma, and it does not provide an assessment response that is necessary for treatment. Most Medicare services do not cover both CEA-Scan and OncoScint since they are a repeat of each other. Tc-99m Arcitumomab can also be contraindicated for patients who are allegoric or experience hypersensitivity to mouse proteins. It can also cause contraindications for expectant patients. References Saha, G. (2004). Fundamentals of nuclear pharmacy. 6th ed. New York: Springer Read More