Simultaneous determination of four secoiridoid and iridoid glycosides in rat plasma by ultra performance liquid chromatography-tandem mass spectrometry and its application to a comparative pharmacokinetic study.

A simple, reliable and rapid ultra-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous quantification of four secoiridoid (gentiopicroside, swertiamarin, sweroside) and iridoid glycosides (loganic acid), the bio-active ingredients in rat plasma. After liquid-liquid extraction, chromatographic separation was accomplished on a Shim-pack XR-ODS column with a mobile phase consisting of methanol and 0.1% formic acid in water. A triple quadrupole tandem mass spectrometry equipped with an electrospray ionization source was used as detector operating both in positive and negative ionization mode and operated by multiple-reaction monitoring scanning. The lower limits of quantitation were 0.25-30 ng/mL for all the analytes. Both intra-day and inter-day precision and accuracy of analytes were well within acceptance criteria (±15%). The mean extraction recoveries of analytes and internal standard (amygdalin) from rat plasma were all >71.4%. The validated method was successfully applied to a comparative pharmacokinetic study of four analytes in rat plasma between normal and arthritic rats after oral administration of Huo Luo Xiao Ling Dan and Gentiana macrophylla extract, respectively. Results showed significant differences in pharmacokinetic properties of the analytes among the different groups.

Metabolites identification of Huo Luo Xiao Ling Dan in rat urine by UPLC coupled with electrospray ionization time-of-flight mass spectrometry.

Huo Luo Xiao Ling Dan (HLXLD), a Chinese herbal formula, is used in folk medicine for the treatment of arthritis and other chronic inflammatory diseases. However, the in vivo integrated metabolism of its multiple components remains unknown. In this paper, an ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS) method was developed for detection and identification of HLXLD metabolites in rat urine at high and normal clinical dosages. The prototype constituents and their metabolites in urine were analyzed. The mass measurements were accurate within 8 ppm, and subsequent fragment ions offered higher quality structural information for interpretation of the fragmentation pathways of various compounds. A total of 85 compounds were detected in high dosages urine samples by a highly sensitive extracted ion chromatograms method, including 31 parent compounds and 54 metabolites. Our results indicated that phase 2 reactions (e.g. glucuronidation, glutathionidation and sulfation) were the main metabolic pathways of lactones, alkaloids and flavones, while phase I reactions (e.g. hydrogenation and hydroxylation) were the major metabolic reaction for coumarins, paeoniflorin and iridoids. This investigation provided important structural information on the metabolism of HLXLD and provided scientific evidence to obtain a more comprehensive metabolic profile.

Systematic chemical profiling of a multicomponent Chinese herbal formula Huo Luo Xiao Ling Dan by ultra high performance liquid chromatography coupled with electrospray ionization quadrupoletime-of-flight mass spectrometry.

Huo Luo Xiao Ling Dan, a Chinese herbal formula consisting of 11 different herbs, has been used in folk medicine for the treatment of arthritis and other chronic inflammatory diseases. However, the chemical compositions of Huo Luo Xiao Ling Dan are not completely characterized. In the present study, an ultra high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry method in positive and negative ion modes was employed to identify biochemical constitutes in Huo Luo Xiao Ling Dan. As a result, a total of 76 compounds including alkaloids, monoterpene glycosides, iridoids, phenolic acids, and tanshinones, coumarins, lactones, flavones, and their glycosides, triterpenes, and triterpene saponins were characterized by comparing the retention time and mass spectrometry data with reference standards within 5 ppm error or by reference to the reference literature. These results would provide the basis for a further in vivo study of Huo Luo Xiao Ling Dan and information for potential new drug candidates for treating arthritis and other chronic inflammatory diseases.

Simultaneous quantitative determination of 20 active components in the traditional Chinese medicine formula Zhi-Zi-Da-Huang decoction by liquid chromatography coupled with mass spectrometry: application to study the chemical composition variations in different combinations.

Zhi-Zi-Da-Huang decoction (ZZDHD), a classical traditional Chinese medicine (TCM) prescription composed of four herbal medicines, has been widely used in treating various hepatobiliary disorders for a long time. The objective of this study was to develop a sensitive and efficient liquid chromatography coupled with mass spectrometry (LC-MS) method for quantitative determination of 20 active constituents, including three iridoid glycosides, 11 flavonoids, three anthraquinones and three tannins in ZZDHD. Separation was achieved on a phenomenex kinetex C18 column (150 × 4.6 mm, 2.6 µm) using gradient elution with a mobile phase consisting of acetonitrile and 0.1% formic acid in water. Detection was performed with electrospray ionization source in the negative ionization and selected ion monitoring mode. The established method was validated by determining the linearity (r(2) ≥ 0.9983), limit of quantification (0.16-300 ng/mL), precision (RSD ≤ 4.6%), average recovery (96.0-105.6%), repeatability (RSD ≤ 3.2%) and stability (RSD ≤ 4.5%). Then, the method was successfully applied to investigate the chemical composition variations owing to the interaction between the four component herbs of ZZDHD during the extraction process. It was found that different combinations of the herbs affect the extraction efficiency of chemical constituents in different ways. The validated LC-MS method provides a meaningful basis for quality control and further research on ZZDHD.

Can the upper inner side of the thigh become a new option for insulin injection?

OBJECTIVE: Sites for subcutaneous insulin injections include the upper arms, abdomen, buttocks and outer sides of the thigh. No similar study has explored the feasibility of using the inner side of the thigh for insulin injection, since the 4 mm pen needles were introduced for clinical use. This study aimed to determine whether the inner side of the thigh is suitable for insulin injection. RESEARCH DESIGN AND METHODS: Seventy-five patients with diabetes under insulin therapy from the Inpatient Department of Endocrinology were recruited for this non-blinded, non-randomized observational study. Subcutaneous adipose layer thicknesses of the upper, middle and lower area of the inner and outer thighs of 35 patients were measured by ultrasound, distance from the skin surface to the femoral deep vessels in 20 patients was measured, and insulin was injected at the upper inner and outer sides of the thigh in 20 patients. Pain perception, bleeding or bruising, leakage at the injection sites, blood glucose changes after insulin injection, and preferred ratings of the patients were measured. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT02307968. RESULTS: Subcutaneous adipose layer thicknesses at both the upper inner and outer thighs were more than 4 mm and the minimum distance was 10 mm. Among the 100 injections at the upper inner thigh, only three incidents of perceived pain occurred. No bleeding or bruising and leakage were observed from the inner or outer sides. Furthermore, the difference in blood glucose control between insulin injections at the inner side and outer sides was not statistically significant. Patient ratings for injections at the inner side were similar to injections at the outer side. The key limitation of this study was the small sample size of adult patients as well as the non-randomized controlled design of this study. CONCLUSION: The upper inner thigh might be a new option for insulin injection rotation.

A UPLC-MS/MS method for simultaneous quantitation of three monoterpene glycosides and four alkaloids in rat plasma: application to a comparative pharmacokinetic study of Huo Luo Xiao Ling Dan and single herb extract.

The objective of this study was to develop a sensitive and reliable ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for simultaneous quantitation of three monoterpene glycosides (paeoniflorin, alibiflorin and oxypaeoniflorin) and four alkaloids (tetrahydropalmatine, corydaline, dehydrocorydaline and berberine), the main active ingredients of Radix Paeoniae Rubra extract (RPE) and Corydalis yanhusuo extract (CYE) in Huo Luo Xiao Ling Dan (HLXLD), and to compare the pharmacokinetics of these active ingredients in normal and arthritic rats orally administrated with HLXLD or RPE/CYE alone. The analytes and internal standard (IS) (geniposide) were separated on a XBridge C18 column (150 × 4.6 mm, 3.5 µm) using gradient elution with the mobile phase consisting of methanol and 0.01% formic acid in water at a flow rate of 0.6 ml/min. The detection of the analytes was performed on Acquity UPLC-MS/MS system with an electrospray ionization and multiple reaction monitoring mode via polarity switching between negative (for monoterpene glycosides) and positive (for alkaloids) ionization mode. The lower limits of quantification were 2.5, 1, 0.5, 0.2, 0.2, 0.02 and 0.01 ng/ml for paeoniflorin, alibiflorin, oxypaeoniflorin, tetrahydropalmatine, corydaline, dehydrocorydaline and berberine, respectively. Intra-day and inter-day precision and accuracy of analytes were well within acceptance criteria (15%). The mean extraction recoveries of analytes and IS from rat plasma were all more than 83.1%. The validated method has been successfully applied to determination of the analytes. Results showed that there were remarkable differences in pharmacokinetic properties of the analytes between herbal formula and single herb group, normal and arthritic group.

Simultaneous determination of seven coumarins by UPLC-MS/MS: Application to a comparative pharmacokinetic study in normal and arthritic rats after oral administration of Huo Luo Xiao Ling Dan or single-herb extract.

A simple, sensitive and reliable ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method has been developed and validated for simultaneous quantitation of seven coumarins, the bio-active ingredients of Huo Luo Xiao Ling Dan (HLXLD), in rat plasma. The liquid-liquid extraction method with ether-dichloromethane (2:1, v/v) was used to prepare the plasma samples. Analytes and internal standard (IS) of bifendate were separated on a Shim-pack XR-ODS column (75mm×3.0mm, 2.2µm particles) using gradient elution with the mobile phase consisting of methanol and 0.05% formic acid in water at a flow rate of 0.4mL/min. Detection was performed on a triple quadrupole (TQ) tandem mass spectrometry equipped with an electrospray ionization source in the positive ionization and multiple reaction monitoring (MRM) mode. The lower limits of quantitation (LLOQ) were 0.03-0.25ng/mL for all the analytes. Intra- and inter-day precision and accuracy of the seven analytes were well within acceptance criteria (15%). The matrix effect and the mean extraction recoveries of the analytes and IS from rat plasma were all within satisfaction. The validated method has been successfully applied to compare pharmacokinetic profiles of the seven active ingredients in rat plasma between normal and arthritic rats after oral administration of HLXLD, Angelica pubescens extract and Notopterygium incisum extract, respectively. Results showed that there were remarkable differences in pharmacokinetic properties of the analytes among the different groups.