The Application Of Nuclear Magnetic Resonance In Complex System Of Drug Study

This thesis concerns the application of the technology of nuclear magnetic resonance (NMR) in the study of the complex system of new drugs, including drug metabolites in the biofluids and the biologically active components in Traditional Chinese Medicine. 1. Searching for a rapid and simple method in the investigation of drug and metabolites in vivo.Solid Phase Extraction Chromatography coupled with NMR detection (SPEC-NMR) was the main technology used in the method. In order to find the adaptability of the method, some new drugs with different structure characteristics were investigated in the study, such as Ambutalide, Meloxicam, Trimebutine, Eperisone, Ibuprofen and Brodimoprim and so on. The solid phase extraction column was used to remove endogenous components from the biofulids (such as rat urine, plasma and liver microsome) rapidly and simply. Drugs and its metabolites were retained and concentrated on the column, the mixture could be detected by NMR (500 MHz) directly. Furthermore, the mixture could be separated with a gradient solvent, and then the fractions were tested on NMR.The method was applied to a range of compounds now, and the results described as follows.Six metabolites of Ambutalide were found in rat urine, N-acetyl-ambutalide, 12-hydroxy-ambutalide glucuronide, 3-hydroxy-6-acetyl-ambutalide, 6-acetyl-12-hydroxy-ambutalide,.11-hydroxy-ambutalide and its glucuronide. The first metabolite was proved by synthesis.Four metabolites of Meloxicam were found in rat urine, 5'-hydroxymethyl derivative, 5'-carboxy derivative, 4-hydroxy-N-[[(2-hydroxypropy)amino]thioxomethyl]2-methyl-2H-1 ,2-benzothiazine-3-carboxamide-1, 1 -dioxide, 5-methyl-5H-pyrimido[5,4-c][1 ,2]benzothiazine-2,4( 1H,3H)-dione-6,6-dioxide.In the study of Trimebutine, four metabolites were detected in rat urine, 2-dimethylamino-2-phenyl-butanol, 3,4,5-trimethoxy-benzoic acid, 2-methylamino-2-phenyl-butanol, 2-amino-2-phenyl-butanol.Three metabolites and one fragment were deduced in the study of Eperison, there were ω-hydroxyl derivative, ω-1 derivative, N-dealkylated derivative, 1-benzyl-propanol and 1-(4-carboxyphenyl)-2-methyl-1-oxo-2-propylene. The last two were found for the first time.A number of problems are encountered when SPEC-NMR method was used for analysis of biofluids. The most important thing was the resolution of the complicated spectrum which include more than one compound, even if the biofluid was fractionated by SPEC column with gradient elution. The resolution method was summarized as follows. (1) The distinct changes of NMR signals between drugs and its metabolites were the key for the...