The study aims to identify the related substances in fasudil hydrochloride by hyphenated techniques. A WondaSil C18 (250 mm x 4.6 mm, 5 microm) column was used for the separation of the related substances with a mixture of methanol and ammonium acetate buffer solution as the mobile phase by gradient elution. The structures of the related substances were speculated by electrospray positive ionization LC-TOF/MS accurate ion mass and MS/MS determination and elucidation, and verified further through synthesis and spectroscopic analysis. Fasudil hydrochloride and the related substances were separated under the established HPLC condition. Three related substances in fasudil hydrochloride were characterized by hyphenated techniques. The hyphenated LC-MS method is useful for the identification of related substances in fasudil hydrochloride and the results obtained are valuable for its manufacturing process and quality control.

A sensitive and selective liquid chromatography–tandem mass spectrometric (LC ? MS/MS) method was established to determine 2-oxo-clopidogrel, a crucial intermediate metabolite in human plasma. A chromatographic separation was performed on a Sapphire C18 column following a liquid–liquid extraction sample preparation with methyl t-butyl ether. Detection was carried out on a triple quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) with an electrospray ionization (ESI) mode. The method was validated in terms of specificity, accuracy, precision and limit of quantification. The calibration curves ranged from 0.50 to 50.0 ng/mL with good linearity. The stability was fully validated with addition of 1,4-dithio-DL-threitol (DTT) into the plasma sample prior to and in the preparation procedure. The validated method was proved to be suitable for use in pharmacokinetic study after single oral administration of 75 mg clopidogrel tablets in human subjects, which could make contribution to intensive study of the clinical drug–drug interactions of clopidogrel and individual treatment.

Object To develop a new method for the determination of curcumol in essential oil from rhizoma Curcumae L.. Methods The contents of curcumol were determined by high performance capillary gas chromatography with sequential increase of temperature on a HEWLETT PACKARD 5890A gas chromatograph. Results The method can be used to determine curcumol with accuracy at a recovery of 101.4% and RSD of 0.40%. Conclusion The present study provided a satisfactory method for the determination of curcumol, and it was found that its contents in four different species (C. wenyujin, C. longa, C. aeruginose, and C. kwangsiensis) were markedly different.

Object To establish the standardization and digit ization methods for gas chromatographic fingerprint chromatograms of the essenti al oil of Curcuma longa L. Methods A polynomial regression analysis technique was estab lished for the calculation and prediction of the gas chromatographic retention i ndices by using a series of normal aliphatic hydrocarbons as the reference stand ards. And it was used for the characterization of the features of the gas chroma tographic fingerprint spectra of the essential oil of C. longa. Results It was approved that retention indices of the gas chrom atographic fingerprint spectra obtained at a variety of conditions were stable and reliable with excellent reproducibility, and fairly good ruggedness. It was also much better than the relative retention time indices. Conclusion The fingerprint spectra standard established on t he multiple references basis are much more reasonable and useful for the practic al quality assurance and validation of Chinese herbals.

Objective To establish a stable and reliable HPLC method and fingerprint reference substance for the measurement of the fingerprint, the practical quality control, and assay of the water-soluble components of Salvia miltiorrhiza. Methods The HPLC was run on C 18 columns with methanol-1.0 % glacial acetic acid solution as mobile phase in gradient elution mode at a flow rate of 1.0 mL/min. The chromatographic system suitability, the gradient elution mode, mobile phase acidity, and the effect of column type on fingerprint repeatability were tested. Results The HPLC fingerprints of the water-soluble extract of reference S. miltiorrhiza were obtained with very good resolution under the established chromatographic system. Fifteen peaks in the chromatograms were selected for the fingerprint identification and quality control of S. miltiorrhiza. The quality of ten batches of S. miltiorrhiza samples from different hibitats were assessed by comparing their chromatographic fingerprints with the reference fingerprints obtained at the same time, and the similarity showed no difference, eventhough the column filler was changed. Conclusion Because the inherent complexity of medicinal material components has been reflected by chromatographic fingerprints, there are many factors affecting the fingerprint repeatability for the changes of column type. The results of the quality assessment of S. miltiorrhiza, using fingerprints from different columns, are not all coincidence. In order to obtain the comparable and repeatable results in different laboratories, it is much practical with both a defined chromatographic system suitability and a fingerprint reference substance.

Objective To isolate and elucidate the structures of alkaloids in Huangyangning. Methods Alkaloids of Huangyangning were separated with preparative HPLC. The molecular structures were elucidated on the basis of chemical evidences and spectral analyses (UV, IR, MS, 1H-NMR, 13C-NMR, COSY, DEPT, HMQC, and HMBC). Results Cyclovirobuxine D is the major component in Huangyangning and cyclobuxine D and cyclovirobuxine C are the two related alkaloids. Conclusion It is demonstrated that all the Huangyangning alkaloids have the same structural frame with only minor differences in substitution through chromatographic and spectral analyses. Therefore, it is not easy to purify cyclovirobuxine D by using usual column, re-crystallization, or chemical approaches for the existence of the related alkaloids.

After oral administration of Salvia miltiorrhiza (Danshen in Chinese), Panax notoginseng (Sanqi in Chinese) and Danshen Sanqi combination suspensions to Beagle dogs, the plasma concentration-time profiles of danshensu, tanshinone II(A), cryptotanshinone, notoginsenoside R1, ginsenoside Rg1 and Rb1 were analyzed by LC-MS/MS. Pharmacokinetic parameters were calculated and analyzed with BAPP 2.0 software. The results showed that the Cmax and AUC of danshensu, notoginsenoside R1, ginsenoside Rg1 and Rb1 in Danshen Sanqi combination group all decreased in comparison with those of Danshen or Sanqi given alone, while the CLz/F and Vz/F increased to some extent. No significant differences of the pharmacokinetics of tanshinone II(A) and cryptotanshinone were observed between groups.

To study the related substances in nicergoline, electrospray positive ionization high resolution TOF/MS was used for the determination of the accurate mass and elemental composition of the related substances. Triple quadrupoles tandem MS/MS was employed for the determination of the fragmentations of the parent ions. 16 related substances were detected and identified to be eight synthetic by-products and eight degradation products, by using impurity references matching, product mass spectra fragmentations elucidation, and verified further according to synthetic processes and stress testing results. The results obtained are valuable for nicergoline manufacturing process control and quality assurance.

An LC-TOF /MS and LC-MS /MS method was established for the identification the related substances in ambrisentan.HPLC separation was carried out on an XBridge C18 column(4.6 mm ×150 mm,3.5 μm)with linear gradient elution using a mobile phase consists of acetonitrile,water and 0.15% formic acid.The structures of the related substances were identified by electrospray positive ESI high resolution TOF /MS and MS /MS spec-tra,and verified further through reference substances.Ambrisentan and its related substances can be separated under the established HPLC conditions.Ten related substances were detected and identified.The established method is useful for the identification of related substances in ambrisentan.The results obtained are valuable for its manufacturing process optimization and quality control.