Study On Separation And Analysis Of Chiral Drugs By Capillary Electrophoresis

This thesis includes the following six chapters:Chaper 1Capillary electrophoresis has unique advantages in separation and analysis of chiral drugs. The fundamental principle, chiral recognition mechanism, the choice of separation conditions and separation models of high performance capillary electrophoresis were introduced in this chaper. Applications of CE in chiral drug separation of recent 5 years were reviewed. This part also provided the background and significance of this research.Chapter 2Conductivity detection was employed for the detection of the enantiomers of bupivacaine hydrochloride (Bup), which were separated by high performance capillary electrophoresis. Computer-aided technique was used to calculate the binding energies and the interaction between Bup enantiomers and CDs was preliminarily discussed. Factors affecting the separation efficiency such as the types and concentration of chiral selectors, running buffer, pH value, separation voltage and capillary inside diameter and length were studied. Under the optimized condition, a baseline separation of Bup enantiomers was achieved in less than 15 minutes in 4 mmol/L NH4Ac-4 mmol/L NaAc (adjusted to pH 4.00 with acetic acid) -0.48 mmol/L sulfobutyl ether-β-cyclodextrin(SBE-β-CD) running buffer at separation voltage of 12 kV. The lowest detective concentration was 0.052μg/ml. The proposed method was suitable for the chiral separation and quantitative analysis of Bup enantiomers in pharmaceutical injection.Chapter 3To establish a HPCE-ECD method for determining the content of enantiomers of bupivacaine hydrochloride in rabbit serum. The running buffer was composed of 4 mmol/L NH4Ac-4 mmol/L NaAc ( adjusted to pH 4.00 with acetic acid) containing 0.48 mmol/L SBE-β-CD, the working voltage was 12 kV. Samples were injected into capillary with a positive voltage of 10 kV for 3 s. The biological samples were alkalized and extracted with chloroform-ethyl ether (10∶1). The enantiomers of bupivacaine hydrochloride were separated at a base line under the above condition in 16 min, and the determination was not interfered by endogenous components from rabbit. This method was high efficient, rapid and low reagent consumption for determining bupivacaine hydrochloride in rabbit serum.Chapter 4A high performance capillary electrophoresis method was established for the chiral separation and determination of nitrendipine and nimodipine enantiomers. An uncoated fused sillica capillary column was used with running buffer of 40 mmol/L sodium dihydrogen phosphate (adjusted to pH 2.96 with phosphoric acid)-10 mmol/L SBE-β-CD, at the applied voltage of -15 kV and the detection wavelength of 237 nm. The resolution of enantiomers of nitrendipine and nimodipine were 3.43 and 2.08. The calibration curves of nitrendipine and nimodipine were linear in the concentration ranges of 5.016~50.16μg/ml and 5.024~50.24μg/ml, with the detection limit of 2.006μg/ml and 2.010μg/ml. (R)- nitrendipine and (S)- nitrendipine average recoveries were 95.86% and 97.04%, with RSDs of 1.15% and 2.06%. (R)- nimodipine and (S)- nimodipine average recoveries were 92.76% and 97.54%, with RSDs of 2.33% and 1.49%. Computer-aided technique was used to calculate the binding energies and the factors affecting the separation efficiency such as the concentration of chiral selectors, running buffer, pH value, separation voltage were studied.Chapter 5To establish a capillary electrophoresis method for the chiral separation and determination of nitrendipine and nimodipine enantiomers in rats plasma. The biological samples were alkalized and extracted with ethyl ether by twice. The running buffer was composed of 40 mmol/L sodium dihydrogen phosphate(adjusted to pH 2.96 with phosphoric acid)-10 mmol/L SBE-β-CD. The detection wavelength was 237 nm. The applied voltage of nitrendipine and nimodipine enantiomers were -18 kV and -15 kV,respectively. Samples were injected into capillary with electric power for 10 s. p-Nitrobenzoic acid was used as internal standard. Enantiomers of nitrendipine and nimodipine were separated at a base line under the above condition, and the determination was not interfered by endogenous components from rats. The linear concentration range of nitrendipine and nimodipine were 28.4~568 ng/ml and 27.4~548 ng/ml,with the detection limit of 11.4 ng/ml and 11.0 ng/ml.Chapter 6A capillary electrophoresis (CE) method with UV detection for the chiral separation and determination of repaglinide enantiomers has been developed. Several parameters such as the composition of the running buffer, the types and concentration of CDs, the pH value, separation voltage, injection time and capillary's inside diameter and length and sample medium which affect the separation, were investigated to acquire the optimum conditions. Under the optimized condition , a baseline separation of repaglinide enantiomers was achieved in less than 15 minutes in 20 mmol/L Tris(Hydroxymethyl)aminomethane ( adjusted to pH 3.90 with phosphoric acid ) -20 mmol/L Hydroxypropyl-β-cyclodextrin (HP-β-CD)running buffer, at the separation voltage of 20 kV and the detection wavelength of 243 nm. The calibration curve for repaglinide was linear in the concentration range of 5.00~50.00μg/ml with the detection limit of 0.25μg/ml. The average recovery was 97.15%, with RSD of 1.21%. The proposed method was suitable for the separation and quantitative analysis of repaglinide enantiomers in pharmaceutical preparation.