Preparation and purification of radioactively labelled fluorescent compounds for medical use
Thesis. Methods of preparation of /sup 203/Hg-labeled fluorescein derivatives and /sup 131/I-trace-labeled folic acid were investigated with a view to develop radioisotopically labeled fluorescent compounds for use in diagnostic medicine as specific localizing and scanning agents with reduced radiation dose to patients. Fluorescein and its derivativcs are labeled with /sup 203/Hg by treating them with /sup 203/Hg-labeled mercuric acid at pH ranging from 3 to 7 and also with /sup 203/Hg-labeled mercuric nitrate at pH ranging from 1 to 7. A pH value of 3 was found to give the best results. For purification of the /sup 203/Hg-labeled product, unbound mercury has to be separated. For separation of unbound mercury from the product, column chromatography on alumina was found better than either acid precipitation, as the product undergoes demercuration at low pH, or cation exchange chromatography. For evaluation of radiochemical purity both paper electrophoresis and paper chromatography methods are found to be unsuitable. A new analytical method based on complexing mercury with thdosulfate ions in paper electrophoresis was developed. This method is found to be suitable for evaluation of the radiochemical purity of some of the other radiomercury organo-mercurials such as 3chloromercuri-2-methoxypropylurea, acetoxymercurd-hvdroxypropane, mercurated bromosulfalein mersalyl, and mersalyl acid. Sterilization by filtering through a bacteriological filter under aseptic conditions does not affect the stability of the labeled product as does sterilization by steam in an autoclave. Studies on shelf life under different conditions are reported. For investigation of tracelabeling of folic acid, /sup 131/I-labeled iodine monochloride, and/sup 131/Ilabeled hypoiodide are used. The latter gives better results, as it gives enhanced specific activity in the labeled compound, and the iodination reaction can be controlled. Out of three methods of purification of the product namely, selective precipitation, removal of iodide using AgCl--AgI suspension, and column chromatography on DEAE- cellulose, the last one is found to be the most effective. Sterilization of the product by bacteriological filter under aseptic conditions is found to be more suitable than sterilization by steam in an autoclave. (lNlS)
- Research Organization:
- Bombay Univ. (India)
- NSA Number:
- NSA-29-002551
- OSTI ID:
- 4409986
- Report Number(s):
- INIS-mf-704
- Resource Relation:
- Other Information: Thesis. Orig. Receipt Date: 30-JUN-74
- Country of Publication:
- India
- Language:
- English
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Related Subjects
*FLUORESCEIN- LABELLING
*FOLIC ACID- PURIFICATION
*IODINE 131- RADIOCHEMISTRY
*MERCURY 203- RADIOCHEMISTRY
*RADIOPHARMACEUTICALS- PURIFICATION
CHROMATOGRAPHY
ELECTROPHORESIS
HYDROXY ACIDS
IODINE CHLORIDES
LABELLED COMPOUNDS
MERCURY NITRATES
ORGANOMETALLIC COMPOUNDS
POLYPHENOLS