Comparative Pharmacokinetic Investigation on Multiple Active Aminoalcohol-Diterpenoid Alkaloids after Single Oral Administrations of Monomers and Aqueous Extract of Fuzi (Aconiti Lateralis Radix Praeparata) by UFLC-MS/MS.

To further study the aminoalcohol-diterpenoid alkaloids (ADAs) in Fuzi (Aconiti Lateralis Radix Praeparata), a simple and sensitive UFLC-MS/MS method was established and validated for the determination of five ADAs, aconine, mesaconine, hypaconine, deoxyaconine and fuziline, in rat plasma to compare the pharmacokinetic characteristics of pure ADAs and Fuzi decoction. After precipitating protein with methanol, plasma samples were isolated at 0.5 mL/min flow rate on Waters Acquity UPLC BEH C18 column (100 mm × 2.1 mm, 1.7 µm). The mobile phase was composed of 0.1% formic acid-water and methanol with gradient elution. Mass spectrometric inspection was conducted on a 5500 UFLC-MS/MS system with an electrospray ionization source in patterns of positive ion and multiple reaction-monitoring (MRM). All calibration curves were proved to have acceptable linearity (r2 > 0.99) in linear ranges. Intra-day and inter-day precision and the accuracy met the requirements. The matrix effects of all analytes were between 85% and 115% of three concentration levels. This method has been under verification for comparative pharmacokinetic research after oral administration between aqueous extract of Fuzi and single pure ADAs. The results demonstrated that there are evident pharmacokinetic discrepancies between them, and administration in the extract form instead of pure form may contribute to higher absorption.

Multi-conformers caused by conformational change of A-ring in the C18- and C19-N-dealkyl diterpenoid alkaloids.

This paper describes a rare phenomenon of multi-conformers caused by conformational change of A-ring in the C18- and C19- N-dealkyl diterpenoid alkaloids. The possible reasons for the generation of multiple conformational isomers are complex, which could be affected by the substituents at C-1, C-3, C-13, C-14, and C-15, pH, solvents, the intramolecular hydrogen bond between 1α-OCH3/1α-OH and N-H groups, acid-base treatment, preparation methods, and work-up procedures.

The in vivo pharmacokinetics, tissue distribution and excretion investigation of mesaconine in rats and its in vitro intestinal absorption study using UPLC-MS/MS.

1. Mesaconine, an ingredient from Aconitum carmichaelii Debx., has been proven to have cardiac effect. For further development and better pharmacological elucidation, the in vivo process and intestinal absorptive behavior of mesaconine should be investigated comprehensively. 2. An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantitation of mesaconine in rat plasma, tissue homogenates, urine and feces to investigate the in vivo pharmacokinetic profiles, tissue distribution and excretion. The intestinal absorptive behavior of mesaconine was investigated using in vitro everted rat gut sac model. 3. Mesaconine was well distributed in tissues and a mass of unchanged form was detected in feces. It was difficultly absorbed into blood circulatory system after oral administration. The insufficient oral bioavailability of mesaconine may be mainly attributed to its low intestinal permeability due to a lack of lipophilicity. The absorption of mesaconine in rat's intestine is a first-order process with the passive diffusion mechanism.

Characterization of degradation products of midazolam maleate by UHPLC-HR-IT-MSn and NMR.

Forced degradation studies on midazolam maleate were carried out according to ICH guidelines. Midazolam maleate was subjected to acidic and basic hydrolysis, oxidation, photolysis, high humidity and thermal stress conditions, and the resulting degradation products were investigated by HPLC. Significant degradation of the drug was observed under acidic/basic hydrolysis and thermal stress conditions. The thermal degradation product (Impurity I) was isolated using column chromatography and its structure was elucidated by UHPLC-HRIT-MSn and extensive NMR studies, which was not reported in previous literatures. The acidic/basic hydrolytic degradation product (Impurity II) was characterized by UHPLC-HR-IT-MSn technique and previous literature. The fragmentation pathways of these two degradation products are also described in the paper.

Fragmentation study of aminoalcohol-diterpenoid alkaloids by electrospray ionization time-of-flight mass spectrometry.

RATIONALE: Aminoalcohol-diterpenoid alkaloids were found to be a group of cardioactive substances in the lateral roots of Aconitum carmichaeli Debx. Studies on the fragmentation behaviors and features of these alkaloids in mass spectrometry would be important for their structural identification and in vivo metabolic research, which has not received much attention thus far. METHODS: In this study, the fragmentation behaviors of 14 aminoalcohol-diterpenoid alkaloids were investigated by utilizing high-resolution time-of-flight tandem mass spectrometry. By analysis of the obtained MS(2) data, we summarized the fragmentation features of the corresponding alkaloids under different collision energy. RESULTS: The dissociation of functional groups from the skeleton was observed as the main fragmentation way in electrospray ionization (ESI) mode. The order of fragmentation sites was C1/C3 > C16 > C15 > C6 > N, with loss of one or more CH3OH, H2O, C2H4 (substituent on N atom) or CO (at C15 ) groups. CONCLUSIONS: The first systematic investigations on the fragmentation of aminoalcohol-diterpenoid alkaloids are described in this paper, setting the stage for an in-depth identification and study of the corresponding components in complex systems.

Simultaneous determination of thirteen aminoalcohol-diterpenoid alkaloids in the lateral roots of Aconitum carmichaeli by solid-phase extraction-liquid chromatography-tandem mass spectrometry.

Aminoalcohol-diterpenoid alkaloids have been reported as the cardioactive components in the lateral roots of Aconitum carmichaeli (Fuzi) according to recent studies. Determination of these effective components is of great significance for quality control purposes for Fuzi. Here we report, for the first, the development and validation of a new method to determine the 13 aminoalcohol-diterpenoid alkaloids in Fuzi by using a simple and accurate solid-phase extraction-liquid chromatography-tandem mass spectrometry. The chromatographic analysis was performed on an ODS column with methanol-0.1 % formic acid (80 : 20, v/v) as the mobile phase. The quantification was performed using MS/MS detection in the positive ion mode with multiple reaction monitoring. Linearity was observed within a range of concentrations of 20-2,000 ng/mL. For all the analytes, the r value was greater than 0.9990. The limit of detection and the limit of quantitation were less than 0.5 ng/mL and 2.0 ng/mL, respectively. The intraday and interday precisions were less than 5% and 10%, respectively. The accuracy was within the range of 90 to 105%. This method was successfully applied to determine the 13 aminoalcohol-diterpenoid alkaloids in Fuzi from different origins and with different processing methods.

[Identification of aminoalcohol-diterpenoid alkaloids in Aconiti Lateralis Radix Praeparata and study of their cardiac effects].

In order to affirm the cardioactive components in Fuzi, we identified a group of aminoalcohol- diterpenoid alkaloids in Fuzi using ultra high-performance liquid chromatography coupled with electrospray ionization mass spectrometer (UPLC-ESI-MS) method. Among a total of forty-one isolated ingredients, thirteen major aminoalcohol-diterpenoid alkaloids were identified by comparing their retention times and MS spectra with those of the reference substances. Moreover, Fuzi samples from different places of origin and with different processing methods were examined and their components displayed a pattern of high similarity, though the relative abundance varies probably due to their different processing methods. Furthermore, the cardiac effect of each identified alkaloid was individually evaluated using the isolated bullfrog heart perfusion experiment. Among the thirteen aminoalcohol diterpenoid alkaloids tested, six of them significantly enhanced the amplitude rates. Taken together, we affirm that the cardioactive components in Fuzi are aminoalcohol-diterpenoid alkaloids, shedding light on future studies of the mechanisms and development of these cardioactive compounds.

Cardioactive C19-diterpenoid alkaloids from the lateral roots of Aconitum carmichaeli "Fu Zi".

Bioassay-guided fractionation of an n-BuOH extract of the lateral roots of Aconitum carmichaeli. led to the isolation of 5 cardioactive C(19)-diterpenoid alkaloids: N-deethylaconine (1), beiwutinine (2), hypaconine (3), mesaconine (4), and 15α-hydroxyneoline (5). N-Deethylaconine and beiwutinine are new aconitine-type C(19)-diterpenoid alkaloids. Hypaconine was isolated from this species for the first time. Among them, mesaconine, hypaconine, and beiwutinine showed the strongest cardiac actions on the isolated perfused bullfrog heart. Furthermore, mesaconine has protective effects, including improved inotropic effect and left ventricular diastolic function, on myocardial ischemia-reperfusion injury in rat at a dose of 10(-9) mol/L. However, mesaconine has almost no effect on heart rate.

On the Famous Traditional Chinese Medicine "Fu Zi": Discovery, Research, and Development of Cardioactive Constituent Mesaconine.

This review summarizes the process of the discovery, research, and development of a cardioactive component, mesaconine, from the lateral roots of Aconitum carmichaelii ("Fu Zi"). To date, pre-clinical showed that mesaconine is a novel type of cardiotonic lead drug with relatively high potency, low toxicity, and a new mechanism.

[Identification of main related substances in potassium sodium dehydroandrographolide succinate].

To identify the structure of three related substances in potassium sodium dehydroandrographolide succinate (PSDS), an HPLC preparation method was used to separate the impurities. These main impurities were identified using LC-ESI/TOFMS, LC-ESI/MSn, NMR, UV and IR. One of the main impurities was a hydrolyzed and oxidized product of PSDS, which has not been reported previouely. The other two impurities were hydrolyzed products of PSDS after losing different succinic acids. The results indicate that PSDS can be easily hydrolyzed and oxidized. It should be stored at cool and dry places.

Characterization of metabolites in rat plasma after intravenous administration of salvianolic acid A by liquid chromatography/time-of-flight mass spectrometry and liquid chromatography/ion trap mass spectrometry.

Salvianolic acid A (SalA) is one of the main active constituents in Salvia miltiorrhiza (Danshen). Although the pharmacokinetics of SalA in rats after intravenous (i.v.) administration of Danshen injection has been reported, the information relevant to the metabolites of SalA in vivo is absent so far. In this study, by means of liquid chromatography with time-of-flight mass spectrometry (LC/TOFMS) and liquid chromatography with ion trap mass spectrometry (LC/MS(n)) techniques, the unknown metabolites of SalA in rat plasma after i.v. administration of the purified SalA at the dose of 20 mg/kg body weight were identified. A liquid-liquid extraction method was established to separate the metabolites from the plasma and the chromatographic separations were performed on a Xterra MS C(18) column (100 mm x 4.6 mm i.d., 3.5 microm) with acetonitrile/methanol/water/formic acid (20.5:19.5:64: 0.05, v/v/v/v) as the mobile phase at a constant flow rate of 0.2 mL/min. Based on the data obtained from the LC/TOFMS determination (the total ion chromatograms, MS spectra and extracted ion chromatograms), in combination with the characteristic fragment ions acquired from the LC/MS(n) determination, five metabolites were identified as SalA-monoglucuronide, monomethyl-SalA-monoglucuronide, mono-methyl-SalA, dimethyl-SalA and dimethyl-SalA-monoglucuronide, and the possible chemical structures were deduced. The results indicated that SalA might mainly undergo two metabolic pathways in vivo in rats, which were methylation and glucuronidation. The present studies have laid a solid foundation for the metabolic mechanism of SalA in vivo.

Determination of Five Aminoalcohol-diterpenoid Alkaloids in the Lateral Root of Aconitum carmichaeli by HPLC-ELSD with SPE.

A convenient and accurate high-performance liquid chromatography coupled with evaporative light scattering detection (HPLC-ELSD) method using solid phase extraction (SPE) was established for quantification of five aminoalcohol-diterpenoid alkaloids (ADAs), including mesaconine, aconine, hypaconine, fuziline and neoline, in the lateral roots of Aconitum carmichaeli (Fuzi) for the first time. The Fuzi extractive was purified using strong cation-exchange SPE. The chromatographic separation was performed on a Gemini C18 column (150 × 4.60 mm, 5 µm) with the mobile phase of methanol-water-diethylamine (48:52:0.01, v/v/v), adjusted to pH 10.2 with acetic acid. The detector was Alltech ELSD 2000ES (drift tube temperature: 90°C; gas flow-rate: 2.3 L/min). Five ADAs in Fuzi were well separated. The calibration curves showed good linearity (r > 0.9990) in the range of 0.0125-0.3750 mg/mL for each alkaloid. The recoveries were in the range of 95.1-105.7%, with relative standard deviations < 5.0%. This method is accurate, specific and repeatable for the determination of five ADAs in different Fuzi samples, which can be applied to the quality control of Fuzi.

Solid lipid nanoparticles of mitoxantrone for local injection against breast cancer and its lymph node metastases.

In an attempt to improve the therapeutic effect of mitoxantrone (MTO) against breast cancer and its lymph node metastases, solid lipid nanoparticles (SLN) of MTO were prepared, characterized and evaluated on mice. Film dispersion-ultrasonication method was used to prepare MTO-SLN, optimized by central composite design. MTO-SLN were prepared with a mean size of 61 nm, drug content (DC) of 4.18+/-0.10% and encapsulation yield (EY) of 87.23+/-2.16%. MTO-SLN were lyophilized and their mean size became 79 nm without significant change in DC and EY. The in vitro release study revealed a profile of sustained release of MTO from MTO-SLN without burst effect: the cumulative release rate Q24 h = 25.86 +/- 0.82%, t50 = (5.25 +/- 1.10)d and t90 = (28.38 +/- 4.50)d. The drug concentration of MTO-SLN in local lymph nodes was much higher and the drug concentrations in other tissues lower than that of MTO solution (MTO-Soln). Human MCF-7 breast cancer in nude mice and animal model of P388 lymph node metastases in Kunming mice were applied to investigate the therapeutic effects. There was no observed toxicity to the main tissues after local injection of MTO-SLN, but, for MTO-Soln, medium to serious toxicity to liver and lung was produced. The percent inhibition of MTO-SLN against breast cancer was 81.81 +/- 14.03%, while that of MTO-Soln with a double dose was 82.86 +/- 11.13%. The tests for lymph node metastases showed that MTO-SLN gave a mean size of lymph node of 41.85 +/- 27.42 mm3, while that of the MTO-Soln was 119.32 +/- 57.30 mm3 and that of the placebo was 186.83 +/- 77.71 mm3. This study opens a new perspective of active delivery of antitumor drug against breast cancer and its lymph node metastases with inspiring therapeutic effect and little side effects.

[Determination of alkaloids in Radix Aconiti Lateralis Preparata by RP-ion-pair HPLC].

AIM: To separate and quantitatively determine six alkaloids: aconitine, mesaconitine, hypaconitine, beiwutine, benzoylaconine and benzoylmesaconine in the Chinese traditional medicine Radix Aconiti Lateralis Preparata (Fuzi). METHODS: A RP-ion-pair HPLC method was established. An AichromBond-1 C18 column was used at a column-temperature of 35 degrees C. The mobile phase was CH3CN5 mmol x L(-1) NaH2PO4(50:50) containing 7 mmol x L(-1) SDS at a flow-rate of 1.0 mL x min(-1). The detector was set at UV 235 nm. RESULTS: These six alkaloids can be completely separated and determined quantitatively. CONCLUSION: This method is accurate and suitable for the determination of six alkaloids in Fuzi.

[Isolation and structure identification of the main photolysis product in vitamin K1].

OBJECTIVE: To isolate and identify an unknown photolysis product in Vitamin K1. METHODS: A column chromatography method was used to prepare the impurity, and spectrometric analyses of ultraviolet spectrum, infrared spectrum, mass spectrum and nuclear magnetic resonance spectrum were carried out to identify its structure. RESULTS: Its structure is 2-methyl-3-(3-hydroxy-3, 7, 11, 15-tetramethyl-1-hexadecenyl)-1, 4-naphthoquinone. CONCLUSION: The structure of the photolysis product has been identified.

Further Studies on Structure-Cardiac Activity Relationships of Diterpenoid Alkaloids.

The cardiac effect of thirty-eight diterpenoid alkaloids was evaluated on the isolated bullfrog heart model. Among them, twelve compounds exhibited appreciable cardiac activity, with compounds 3 and 35 being more active than the reference drug lanatoside. The structure-cardiac activity relationships of the diterpenoid alkaloids were summarized based on our present and previous studies [2]: i) 1α-OMe or 1α-OH, 8-OH, 14-OH, and NH (or NMe) are key structural features important for the cardiac effect of the aconitine-type C19-diterpenoid alkaloids without any esters. C18-diterpenoid alkaloids, lycoctonine-type C19-diterpenoid alkaloids, and the veatchine- and denudatine-type C20-diterpenoid alkaloids did not show any cardiac activity; ii) the presence of 3α-OH is beneficial to the cardiac activity; iii) the effect on the cardiac action of 6α-OMe, 13-OH, 15α-OH, and 16-demethoxy or a double bond between C-15 and C-16 depends on the substituent pattern on the nitrogen atom.

[Determination of danshensu in urine and its pharmacokinetics in human].

AIM: To determine Danshensu in urine and study its pharmacokinetics in human. METHODS: A solid phase extraction-HPLC method was used for determination of Danshensu in urine of human. HPLC separation is performed on a Shim-pack CLC-ODS column (150 mm x 6.0 mm ID, 5 microns) with a mobile phase composed of acetonitrile -0.01 mol.L-1 KH2PO4 (adjusted to pH 2.8 with phosphoric acid). The flow rate was 1.0 mL.min-1 and the UV detector was set at 280 nm. The linear range of Danshensu was 0.2-50 mg.L-1 (r = 0.9999), and its limit of detection was 1.5 ng. The mean recovery was 99.4% (RSD = 2.9%). RESULTS: The pharmacokinetics of Danshensu after p.o. administration of two kinds of pharmaceutical preparations containing Danshen (with 20 mg of Danshensu) were investigated in 6 healthy human volunteers by determining the Danshensu in urine samples. The elimination half lives (T1/2) of Danshensu after p.o. administration of compound granule preparation A and decoction of Danshen were (0.92 +/- 0.16) h and (0.94 +/- 0.21) h, respectively. Their excretions of Danshensu in urine were (6.2 +/- 2.8)% and (14 +/- 4)% of the dose in 8 hours, respectively. CONCLUSION: Under normal doses, Danshensu can be eliminated from kidney. There is no evident difference on elimination half lives of Danshensu after p.o. administration of the two doses, but the excretions of Danshensu by urine after p.o. administration of compound granule preparation A were lower than that of decoction of Danshen.

[Determination of progesterone and its main metabolite in rat plasma and uterus using HPLC].

AIM: To quantify progesterone (P) and one of its metabolites 20alpha-hydroxy-4-pregnen-3-one (20alpha-OHP) in rat plasma and uterus after im administration of progesterone. METHODS: Plasma and uterus samples were prepared by liquid-liquid extraction and separated through Shimadzu VP-ODS column (150 mm x 4.6 mm ID, 5 microm). The mobile phase consisted of acetonitrile and water (60: 40, adjusted to pH 4.0 with phosphoric acid). The detector was set at 240 nm. Norgestrel was used as the internal standard. RESULTS: Cmax of P in plasma was (508 +/- 62) microg x L(-1), Tmax was (3.2 +/- 0.4) h, T1/2 (ke) was (10 +/- 4) h and mean AUC0-48h was (5886 +/- 1573) microg x L(-1) x h. The maximum concentration of P in uterus was (1.7 +/- 1.1) microg x g(-1) and the peak time was (5.2 +/- 1.11) h. 20alpha-OHP showed a similar Tmax with P. CONCLUSION: The method is accurate and convenient. It can be used to determine P and its main metabolite 20alpha-OHP simultaneously for studying their preclinical pharmacokinetics.

[Determination of creatine, phosphocreatine and adenosinephosphates in experimental hydrocephalus tissue by reversed-phase high performance liquid chromatography].

OBJECTIVE: To investigate the state of impaired cerebral energy metabolism of the hydrocephalus tissue. METHODS: Adult male dogs were used for establishing the model of kaolin-induced hydrocephalus. A simple and rapid method for the simultaneous determination of creatine (Cr), phosphocreatine (Crp), and adenosinephosphates (AMP, ADP, ATP) in different stages of experimental hydrocephalus tissue by reversed-phase high performance liquid chromatography (RP-HPLC) has been established. The chromatographic conditions were as follows: Inertsil ODS-3 C18 column (4.6 mm x 250 mm i.d. 5 microns), the mobile phase being composed of KH2PO4 buffer (330 mmol/L)-acetonitrile-TBA (45 mmol/L) (94:5.5:0.5) (pH = 6.27) and detector at 210 nm. RESULTS: The calibration curve showed a good linearity in the mass concentration range of 5.69-3640.50 mumol/L (r = 0.9993) for Cr, 3.47-555.50 mumol/L (r = 0.9999) for Crp, 2.69-1723.00 mumol/L (r = 0.9993) for AMP, 2.66-1704.00 mumol/L (r = 0.9999) for ADP and 2.94-1883.50 mumol/L (r = 0.9999) for ATP. The recoveries ranged from 90.10% to 107.00% with relative standard deviations from 1.58% to 3.88%. The detection limits of this method were 3.55-5.84 mumol/L. By means of this method, the Cr, Crp, AMP, ADP and ATP in different stages of 16 dogs experimental hydrocephalus tissue were determined with satisfactory results. CONCLUSION: This method is rapid, precise, accurate and suitable for the determination of the high energy nucleotides in hydrocephalus tissues.

Noninvasive measurement of glucose in artificial plasma with near-infrared and Raman spectroscopy.

The goal of this research was to develop a method for noninvasive blood glucose assay. Near-infrared (NIR) spectroscopy and Raman spectroscopy, two more promising techniques compared to other methods, were investigated in two kinds of artificial plasma (AP). Calibration models were generated by performing partial least squares (PLS) regression and optimized individually by considering spectral range, spectral pretreatment methods, and number of model factors. The two spectroscopic models were validated for the determination of glucose, and the results show that the two spectroscopic models established are robust, accurate, and repeatable. Compared to Raman spectroscopy, the performance of NIR spectroscopy was much better, with lower root mean square errors of cross-validation (RMSECV) of 0.128 and 0.094 mg/ml, lower root mean square errors of validation (RMSEP) of 0.061 and 0.046 mg/ml, higher correlation coefficients (R) of 99.15% and 99.55%, and higher residual predictive deviations (RPD) of 10.8 and 15.0 for artificial plasma I and II, respectively.