Investigation Of Chiral Separation Of Drugs Collected In Chinese Pharmacopoeia2010(Ch.P2010)

Biggish differences exist among optical enantiomers of chiral drugs in pharmacodynamics and toxicity. It is mainly due to the fact that receptors and enzymes possess special stereo-selectivity to different enantiomers of drugs in the process of absorption, distribution, metabolism and elimination. Therefore, the studies on pharmacokinetics and pharmacodynamics for the single enantiomer should be explored to ensure drugs to be reasonable, safe and reliable in the clinical usage. To guarantee the quality of the enantiomer for the pharmacological research, an analytical method of separation for drug enantiomers is indispensable to establish. Up to now, the separation methods for chiral drug have been reported on chemical separation, crystallization method, biological separation, and chromatography method, etc. It has indicated that chromatography could be deemed as the best effective way based on simplicity, convenience, and accuracy.This thesis comprising of three parts is concerned with the chiral separation of some drugs by HPLC methods including Chiral Solid Phase (CSP) and Chiral Mobile Phase (CMP).Above all, the study is concerned with the enantiomers separation of thirteen pharmaceutical racemates collected in Ch.P2010. It was performed on chiral stationary phase of amylose and cellulose ramifications by high performance liquid chromatographic (HPLC) methods, which was included ibuprofen, ketoprofen, nitrendipine, nimodipine, felodipine, omeprazole, praziquantel, propranolol hydrochloride, atenolol, sulpiride, clenbuterol hydrochloride, verapamil hydrochloride, and chlorphenamine maleate. The racemates were separated on Chiralcel OJ column, Chiralcel OD column, Chiralpak AD-H column and Chiralpak AS-H column as stationary phase, and the mobile phase consisted of isopropanol and n-hexane. The detection wavelength and the flow rate were set at254nm and0.7mL/min, respectively. The enantiomers separation of these thirteen racemates on Chiralcel OJ column, Chiralcel OD column, Chiralpak AD-H column and Chiralpak AS-H column was studied, while the effects of proportion of organic additives and alcohol displacer, temperature on the separation were investigated. Clenbuterol hydrochloride, nitrendipine and praziquantel had a good separation with a pair of enantiomers on AD-H column, but verapamil hydrochloride and omeprazole were not separated entirely with the resolution value of0.7and0.5. Felodipine, sulpiride, clenbuterol hydrochloride and chlorphenamine maleate were able to be separated completely with a pair of peaks of enantiomers on AS-H column. Nimodipine, omeprazole, praziquantel and propranolol hydrochloride, atenolol were performed a well separation with a pair of enatiomers on OD-H column, while sulpiride had not been separated fully with the resolution value of0.9. The chromatographic separation on Chiralcel OJ-H column was very different from that on Chiralcel OD-H column for the same sample. Ibuprofen, ketoprofen, felodipine, omeprazole, Clenbuterol hydrochloride and chlorphenamine maleate were able to be separated completely with a pair of peaks of enatiomers. Nitrendipine and nimodipine can be separated with a resolution value of0.7and1.2, respectively. The results indicated that thirteen chiral drugs could be separated on chiral stationary phase in normal phase chromatographic system. The chromatographic retention and resolution of enantiomers could be adjusted by factors including the changes of the concentration of alcohol displacer in mobile phase and organic alkaline modifier and column temperature. The result showed that the resolution was improved with reducing concentration of alcohol displacer. When the concentration of organic alkaline modifier was0.2%, the resolution and the peak shape were fairly good. Most racemates mentioned above had the best resolution at column temperature of25℃. When racemates were separated, the best temperature should be kept unchanged so as to obtain stable separation results.One the other hand, this thesis is also concerned with the separation of the chiral drugs using two neutral cyclodextrins (β-Cyclodextrin(β-CD) and2-hydroxypropyl-β-cyclodextrin (HP-β-CD)) and a negative cyclodextrin sulfobutylether-β-cyclodextrin(SBE-(β-CD) as chiral mobile phase additives while the effects of proportion of organic additives, alcohol displacer and temperature on the separation were investigated. The mechanism of some racemates was discussed. Fifteen pharmaceutical racemates collected in Ch.P2010were performed with a good separation in this study.