Reconstitution radiopharmaceuticals

Kits. Kits for the preparation of radiopharmaceuticals are a convenient solution to synthesis of products containing short-Hved radionucHdes (eg, In, I, Tc) bound to a nonradio active moiety. The labeling step is performed either at a commercial radiopharmacy, or within the institutional nuclear medicine laboratory. The kits are usually stored as a frozen solution or lyophilized product. The material of interest is then metered out into kit dosages. The kit vials are thawed or reconstituted and mixed with the appropriate radionucHde. 

General trends in radiopharmaceutical research emphasize the use of small peptides. These molecules, of which the agents mentioned for thrombosis localization are an example, exhibit rapid and specific binding, and rapid blood clearance, two important parameters for a successflil radiopharmaceutical. Peptides are readily labeled with Tc and lend themselves to formulation as lyophilized kits that can be rapidly and rehably reconstituted. Possible targets for these molecules are quite varied, ranging from atherosclerotic plaque to P-amyloid (for Alzheimer s disease), to a variety of somatic receptors the populations of which are increased or decreased in disease. 

It should not be necessary to perform HPLC on radiopharmaceuticals reconstituted from licensed cold kits. It is useful to have techniques available for the purpose of eliminating a cause of any abnormal patient scan. For radiopharmaceuticals prepared in-house or novel compounds for research purposes, an HPLC method for estimating RCP is essential. It should be noted that HPLC does not detect colloidal contaminants and that this should be estimated using TLC methods. 

Finally, the occurrence of one and only one stereoisomer is an important chemical requirement. The formation of isomers upon, e.g., the reconstitution of cold kits can be connected to the properties of the metal fragment the ligand coordinates to and/or to the ligand as such. It is difficult to predict whether different complex isomers such as stereoisomers, enantiomers, diastereomers, and others will exhibit a comparable biological behavior and, thus, lead to a useful radiopharmaceutical. It has been shown and will be discussed later in this text that even enantiomers can alter the bioactivity of the vectors they are linked to in a significant way. 

The preparation of a radiopharmaceutical in routine application is usually done in a one-or two-step procedure. O Figure 43.1 gives in the context of coordination chemistry later an overview of the different processes for the production of a radiopharmaceutical in relation to the required fundamental coordination chemistry. Perfusion agents such as pure complexes can be prepared in most cases in one single step upon kit reconstitution. The kit is a vial that contains all the ingredients necessary for performing the chemical reaction to form the... 

Also in this situation a separate room is required for preliminary operations, e.g. disinfection of utensils and surfaces of materials. In the preparation room medicines are reconstituted, e.g. filling of syringes, infusion bags, medication cartridges, disposable infusion pumps and irrigations. In addition, parenteral nutrition fluids, antineoplastics, radiopharmaceuticals and eye preparations may be prepared in these premises. Radiopharmaceuticals and other very... 

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