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.

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.

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.

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.

Inosiplex is a compound formulation composed of inosine and p-acetaminobenzoic acid (PABA) salt of N,N-dimethylamino-2-propanol (DIP). This study was to investigate the clinical plasma pharmacokinetic properties of DIP and PABA after single and multiple oral doses of inosiplex tablets in healthy Chinese volunteers. The established LC/MS/MS method for plasma DIP determination had a linear range of 0.02-10 mg/mL, and the HPLC method for plasma PABA determination had a linear range of 0.05-40 mg/mL. Linear pharmacokinetic characteristics were found with single oral doses of 0.5, 1.0 and 2.0 g. No obvious accumulation effects were observed for DIP and PABA.

Objective: To establish a method for determining the molecular weight and molecular weight distribution of Poly(Lactide-co-Glycolide Acid) (PLGA) using Size Exclusion Chromatography-Refractive Index-Multiangle Laser Light Scattering (SEC-RI-MALLS) and Size Exclusion Chromatography-Refractive Index (SEC-RID), and to compare the results obtained from these two methods.
Methods: For SEC-RI-MALLS, tetrahydrofuran was used as the mobile phase, Shodex GPC KF-803L was employed as the chromatographic column with a flow rate of 1 mL·min^-1, column temperature at 30 ℃, and an injection volume of 100 μL. For SEC-RID, tetrahydrofuran was also used as the mobile phase, Agilent PLgel 5 μm MIXD-D was used as the chromatographic column with a flow rate of 1 mL·min^-1, column temperature at 30 ℃, differential detector temperature at 35 ℃, and an injection volume of 20 μL. The molecular weight and molecular weight distribution were calculated using Agilent’s GPC software. The newly established methods were validated methodologically, and the molecular weight and molecular weight distribution of 13 batches of samples were determined.
Results: The precision, accuracy, stability, and repeatability tests for SEC-RI-MALLS showed RSD values of 1.35%, 1.58%, 1.53%, and 1.26%, respectively. The SEC-RID method exhibited good linearity (r=0.999 9), with RSD values for precision, accuracy, stability, and repeatability tests (n=6) of 2.05%, 1.62%, 1.30%, and 2.97%, respectively. The results obtained from SEC-RI-MALLS were lower than those from SEC-RID, and the molecular weight distribution coefficient was smaller, but the results from the paired T-test performed with the value measured by SEC-RID method and the value measured by SEC-RI-MALLS method multiplied a conversion coefficient of 1.5 showed no significant difference between the two methods.
Conclusion: Both methods are stable and reliable, and can be used for the determination of PLGA molecular weight and molecular weight distribution based on the specific situations.

An LC-MS method was established for the identification of the related substances in rivaroxaban. HPLC separation was carried out on an Inert Sustain C18 column(250 mm×4. 6 mm, 5 μm)with linear gradient elution using a mobile phase consisting of 0. 2% formic acid acetonitrile and 0. 2% formic acid aqueous solution. Rivaroxaban and its related substances could be completely separated under the established HPLC conditions. The structures of the related substances were identified by electrospray positive ESI high resolution TOF/MS and MS/MS spectra determination and elucidation, and further verified through reference substances. Fifteen related substances were detected and identified to be three related substances of starting materials, four synthetic by-products and ten degradation products. The established method is useful for the identification of the related substances in rivaroxaban. The results obtained are valuable for its manufacturing control and quality assurance.