Liquid chromatography tandem mass spectrometry in study of the pharmacokinetics of six steroidal saponins in rats

A new insight into material basis of rhizoma Paridis saponins in alleviating pain

ETHNOPHARMACOLOGICAL RELEVANCE

Paris polyphylla, as a traditional Chinese herbal medicine, was often used to relieve inflammation and pain. Rhizoma Paridis saponins (RPS) as the main active components of Paris polyphylla have excellent analgesic effects.

AIM OF THE STUDY

Determine the analgesic material basis of RPS.

MATERIALS AND METHODS

LC-MS/MS was used to analyze RPS, plasma after intravenous injection of RPS, and oral administration of RPS. H22 plantar pain model was established to explore the analgesic material basis of RPS. Moreover, correlation analysis, network pharmacology, RT-PCR and molecular docking were applied in this research.

RESULTS

RPS had dose-dependently analgesic effects in acetic acid- and formalin-induced pain models. LC-MS/MS detection indicated that diosgenin as the metabolite of RPS mainly distributed in brain tissues. The addition of antibiotics increased the anti-tumor effect of RPS, but reduced its analgesic effect. Network pharmacology, RT-PCR and molecular docking showed that diosgenin exerted its analgesic effect through SRC and Rap1 signaling pathway.

CONCLUSION

Diosgenin exhibited analgesic effects, while saponins had good anti-tumor effects in RPS. This discovery provided a better indication for the later application of RPS in anti-tumor and analgesic settings.

Anticancer Potential of the Plant-Derived Saponin Gracillin: A Comprehensive Review of Mechanistic Approaches

With the increasing prevalence of cancer and the toxic side effects of synthetic drugs, natural products are being developed as promising therapeutic approaches. Gracillin is a naturally occurring triterpenoid steroidal saponin with several therapeutic activities. It is obtained as a major compound from different Dioscorea species. This review was designated to summarize the research progress on the anti-cancer activities of gracillin focusing on the underlying cellular and molecular mechanisms, as well as its pharmacokinetic features. The data were collected (up to date as of May 1, 2023) from various reliable and authentic literatures comprising PubMed, Springer Link, Scopus, Wiley Online, Web of Science, ScienceDirect, and Google Scholar. The findings demonstrated that gracillin displays promising anticancer effects through various molecular mechanisms, including anti-inflammatory effects, apoptotic cell death, induction of oxidative stress, cytotoxicity, induction of genotoxicity, cell cycle arrest, anti-proliferative effect, autophagy, inhibition of glycolysis, and blocking of cancer cell migration. Additionally, this review highlighted the pharmacokinetic features of gracillin, indicating its lower oral bioavailability. As a conclusion, it can be proposed that gracillin could serve as a hopeful chemotherapeutic agent. However, further extensive clinical research is recommended to establish its safety, efficacy, and therapeutic potential in cancer treatment.

The Pharmacokinetics and Tissue Distributions of Nine Steroidal Saponins from Paris polyphylla in Rats

BACKGROUND AND OBJECTIVES

Paris polyphylla (P. polyphylla) is a herb widely used in traditional Chinese medicine to treat various diseases. This study used ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to study the pharmacokinetics and tissue distributions of nine steroidal saponins from P. polyphylla.

METHODS

P. polyphylla extract was administered to rats intravenously (i.v.) and orally (p.o.). The concentrations of the nine main bioactive components of the extract were determined in plasma and tissue samples using UPLC-MS/MS. The nine saponin compounds were also incubated in an anaerobic environment with intestinal flora suspension solution to investigate hydrolysis by intestinal flora.

RESULTS

After oral administration of the P. polyphylla extract, polyphyllin VII was found to have the highest maximum concentration (C_max, 17.0 ± 2.24 µg/L) of all nine components, followed by the C_max values of dioscin (16.17 ± 0.64 µg/L) and polyphyllin H (11.75 ± 1.28 µg/L), while the C_max values of polyphyllin I, polyphyllin II, progenin III, polyphyllin IV, gracillin, and polyphyllin were less than 10 µg/L. The bioavailabilities of all nine components were less than 1%. All the compounds were hydrolyzed by intestinal flora and were predominantly distributed in the liver and lungs.

CONCLUSIONS

The nine compounds presented different pharmacokinetic parameter values, and multiple administrations did not accumulate in the body. The bioavailabilities of the compounds were low, partly because of hydrolysis by intestinal flora. The nine compounds were mainly distributed in the liver and lungs, which may be target organs.

Tissue distribution, metabolism and absorption of Rhizoma Paridis Saponins in the rats

ETHNOPHARMACOLOGICAL RELEVANCE

Paris polyphylla var yunnanensis as a traditional Chinese medicine has been used in the treatment of liver disease for thousands of years. Rhizoma Paridis saponins (RPS) were the main active ingredients in Paris polyphylla with an excellent antitumor effect. However, metabolic and distribution of RPS has not been known.

AIM OF THE STUDY

The objective of this study was to research metabolic and distribution of RPS.

MATERIALS AND METHODS

In this study, the separation and simultaneous determination of RPS in rat plasma and tissues were developed and validated by LC-MS/MS. The permeability and recovery of RPS were tested by Caco-2. S9 assay suggested the metabolic mode of RPS in rats.

RESULTS

After oral administration of RPS, the metabolic compound like diosgenin was detected in different tissues although there was none in RPS. The concentration of PI, PII, PVI, PVII, PH and gracillin in the spleen was the highest among these organs. The content of diosgenin were the highest in lung and brain. Caco-2 test indicated that PI, PII, PVI and PVII were low permeability and low recovery. Efflux ratio indicated that PVI should be a potential P-gp substrate. Potential P-gp substrate may be PVI. S9 assay suggested that RPS possess slow metabolic and moderate metabolic compounds.

CONCLUSIONS

Integrated LC-MS/MS analysis of serum samples, together with Caco-2 and S9 assays provided a theoretical basis for the application of RPS in the future.

Natural Deep Eutectic Solvents for the Extraction of Bioactive Steroidal Saponins from Dioscoreae Nipponicae Rhizoma

In the present study, a simple and environmentally friendly extraction method based on natural deep eutectic solvents (NADESs) was established to extract four bioactive steroidal saponins from Dioscoreae Nipponicae Rhizoma (DNR). A total of twenty-one types of choline chloride, betaine, and L-proline based NADESs were tailored, and the NADES composed of 1:1 molar ratio of choline chloride and malonic acid showed the best extraction efficiency for the four steroidal saponins compared with other NADESs. Then, the extraction parameters for extraction of steroidal saponins by selected tailor-made NADES were optimized using response surface methodology and the optimal extraction conditions are extraction time, 23.5 min; liquid–solid ratio, 57.5 mL/g; and water content, 54%. The microstructure of the DNR powder before and after ultrasonic extraction by conventional solvents (water and methanol) and the selected NADES were observed using field emission scanning electron microscope. In addition, the four steroidal saponins were recovered from NADESs by D101 macroporous resin with a satisfactory recovery yield between 67.27% and 79.90%. The present research demonstrates that NADESs are a suitable green media for the extraction of the bioactive steroidal saponins from DNR, and have a great potential as possible alternatives to organic solvents for efficiently extracting bioactive compounds from natural products.

Natural Polyphyllins (I, II, D, VI, VII) Reverses Cancer Through Apoptosis, Autophagy, Mitophagy, Inflammation, and Necroptosis

Cancer is the second leading cause of mortality worldwide. Conventional therapies, including surgery, radiation, and chemotherapy, have limited success because of secondary resistance. Therefore, safe, non-resistant, less toxic, and convenient drugs are urgently required. Natural products (NPs), primarily sourced from medicinal plants, are ideal for cancer treatment because of their low toxicity and high success. NPs cure cancer by regulating different pathways, such as PI3K/AKT/mTOR, ER stress, JNK, Wnt, STAT3, MAPKs, NF-kB, MEK-ERK, inflammation, oxidative stress, apoptosis, autophagy, mitophagy, and necroptosis. Among the NPs, steroid saponins, including polyphyllins (I, II, D, VI, and VII), have potent pharmacological, analgesic, and anticancer activities for the induction of cytotoxicity. Recent research has demonstrated that polyphyllins (PPs) possess potent effects against different cancers through apoptosis, autophagy, inflammation, and necroptosis. This review summarizes the available studies on PPs against cancer to provide a basis for future research.

Pharmacokinetics profiles of polyphyllin II and polyphyllin VII in rats by liquid chromatography with tandem mass spectrometry

Polyphyllin II (PII) and polyphyllin VII (PVII) are the main active ingredients in Paris Polyphylla with an excellent antitumor effect in vitro and in vivo. In this study, a rapid and precise LC-MS/MS method was developed and validated for the separation and simultaneous determination of PII and PVII in rat plasma, tissues, feces and urine using ginsenoside Rg3 as the internal standard. Positive linearity ranged from 1 to 1,000 ng/ml in samples. At the same time, intra- and inter-day precisions were in range of 1.8-12.0%. The accuracy ranged from 95.9 to 100.8%. Mean extraction recoveries of PII and PVII ranged from 86.6 to 96.4%. The analytical method has been successfully applied to the pharmacokinetic studies of PII and PVII in rats after their i.v. administration. After entering systemic circulation, PII and PVII were rapidly distributed in organs, mainly including liver, lung and spleen. Their elimination rate was slow. All of these data provided a theoretical basis for the application of PII and PVII in the treatment of liver- and lung-related diseases.

Molecular mechanisms of anticancer activities of polyphyllin VII

Cancer is the leading cause of mortality in the world. The major therapies for cancer treatment are chemotherapy, surgery, and radiation therapy. All these therapies expensive, toxic and show resistance. The plant-derived compounds are considered safe, cost-effective and target cancer through different pathways. In these pathways include oxidative stress, mitochondrial dependent and independent, STAT3, NF-kB, MAPKs, cell cycle, and autophagy pathways. One of the new plants derived compounds is Polyphyllin VII (PPVII), which target cancer through different molecular mechanisms. In literature, there is a review gap of studies on PPVII; therefore in the current review, we summarized the available studies on PPVII to provide a base for future research.

A rapid method for on-line solid-phase extraction and determination of dioscin in human plasma using a homemade monolithic sorbent combined with high-performance liquid chromatography

A phenyl-based polymer monolithic column was prepared via free radical polymerization in a stainless steel column with the size of 4.6 mm i.d. × 50 mm, using ethylene glycol phenyl ether acrylate as the monomer. The resulting monolithic column shows high porosity of 73.42% and relative uniform pore structure, as characterized by mercury porosimetry and scanning electron microscopy, respectively. The optimized polymer monolith column was used for on-line solid-phase extraction prior to the reversed phase mode HPLC-UV analysis for the determination of dioscin in human plasma, using a COSMOSIL C18 column (4.6 mm × 150 mm, 4.5 μm). Water was used to wash non-retained components from the SPE sorbent, and methanol water (80:20, V/V) was used as the mobile phase for isocratic elution of dioscin. The maximum adsorbed quantity of dioscin to the SPE column is 6.79 mg/g, which is high enough for the quantitative analysis of dioscin in plasma, due to the low content of dioscin in plasma. The method was validated by assessing the linearity, lower limit of quantification, intra- and inter-day precision, accuracy, and repeatability. The developed method was applied for the analysis of dioscin in plasma from a volunteer who had orally administered an aqueous extract of dioscorea nipponica rhizome, showing the method capable of detecting dioscin in the plasma. These results show that the developed method is a rapid method for on-line solid-phase extraction and determination of dioscin from plasma, exhibiting good selectivity with hydrogen bond interaction and hydrophobic interaction, good clean-up ability, cost-saving, and time-saving. Graphical abstract.

Curcumin enhances the anti-cancer effects of Paris Saponin II in lung cancer cells

OBJECTIVES

To investigate the synergistic mechanisms of Paris Saponin II (PSII) and Curcumin (CUR) in lung cancer.

MATERIALS AND METHODS

The combination changed the cellular uptake of CUR and PSII, apoptosis, cell cycle arrest and cytokine levels were analysed on different lung cancer cells.

RESULTS

The combination displayed a synergistic anti-cancer effect through promoting the cellular uptake of CUR on different lung cancer cells. Hoechst H33258 staining and FACS assay indicated that the combination of PSII and CUR induced cell cycle arrest and apoptosis. Western blot and cytokine antibody microarray suggested that the combination activated death receptors such as DR6, CD40/CD40L, FasL and TNF-α to induce cancer cells apoptosis, and up-regulated IGFBP-1 leading to inhibition of PI3K/Akt pathway and increase of p21 and p27, which therefore induced a G2 phase arrest in NCI-H446 cells. Meanwhile, the combination suppressed PCNA and NF-κB pathway in 4 kinds of lung cancer cells. They activated the phosphorylation of p38 and JNK, and inhibited PI3K in NCI-H460 and NCI-H446 cells, enhanced the phosphorylation of JNK in NCI-H1299 cells, and increased the phosphorylation of p38 and ERK, and suppressed PI3K in NCI-H520 cells.

CONCLUSIONS

PSII combined with CUR had a synergistic anti-cancer effect on lung cancer cells. These findings provided a rationale for using the combination of curcumin and PSII in the treatment of lung cancer in future.

Effect of Rhizoma Paridis saponin on the pain behavior in a mouse model of cancer pain

Rhizoma Paridis saponins (RPS) as active parts of P. polyphylla Smith var. yunnanensis has been used as an anti-cancer drug in traditional Chinese medicine. In this study, RPS was first found to demonstrate a potent effect on markedly reducing the pain induced by cancer. Therefore, the aim of this study was to further explore the analgesic effect of RPS and its possible reaction pathway on H22 hepatocarcinoma cells inoculated in the hind right paw of mice. Cancer-induced pain model mice were randomly divided into 5 groups (n = 10) and orally administered with RPS (50–200 mg kg⁻¹) for 2 weeks. On the last day of treatment, the pain behavior of mice was measured using hot-plate test and open field test, and brain tissues were sampled for detection of biochemical indices, malondialdehyde (MDA), superoxide dismutase (SOD), prostaglandin E2 (PGE2), serotonin (5-HT) and β-endorphin (β-EP). Moreover, the concentrations of NF-κB and IL-1β in the blood serum were measured by ELISA reagent kits. In addition, naloxone, the non-selective antagonist of opioid receptors, was used to identify the opioid receptors involved in RPS's action. It has been found that RPS alleviates cancer pain mainly via the suppression of inflammatory pain induced by oxidative damage, such as decreasing MDA and PGE2 levels, renewing activity of SOD, as well as increasing 5-HT and β-EP in the brain and suppressing the expression of NF-κB and IL-1β in the serum in a concentration-dependent manner. Overall, the current study highlights that RPS has widespread potential antinociceptive effects on a mouse model of chronic cancer pain, which may be associated with the peripheral nervous system and the central nervous system.

Rhizoma Paridis saponins (RPS) as active parts of P. polyphylla Smith var. yunnanensis has been used as an anti-cancer drug in traditional Chinese medicine.

A new agent developed by biotransformation of polyphyllin VII inhibits chemoresistance in breast cancer

Biotransformation by the endophytes of certain plants changes various compounds, and this ‘green’ chemistry becomes increasingly important for finding new products with pharmacological activity. In this study, polyphyllin VII (PPL7) was biotransformed by endophytes from the medicinal plant Paris polyphylla Smith, var. yunnanensis. This produced a new compound, ZH-2, with pharmacological activity in vitro and in vivo. ZH-2 was more potent than PPL7 in selectively killing more chemoresistant than chemosensitive breast cancer cells. ZH-2 also re-sensitized chemoresistant breast cancer cells, as evidenced by the improved anti-cancer activity of commonly-used chemotherapeutic agent in vitro, in vivo, and in clinical samples. This anti-chemoresistance effect of ZH-2 was associated with inhibiting the epithelial-mesenchymal transition (EMT) pathway. Taken together, our findings are the first one to link biotransformation with a biomedicine. The results provide insights into developing new pharmacologically-active agents via biotransformation by endophytes.

Determination and pharmacokinetics of engeletin in rat plasma by ultra-high performance liquid chromatography with tandem mass spectrometry

Engeletin, a bioactive flavonoid, has attracted much attention recently by virtue of its multiple biological (anti-diabetic and anti-inflammatory) activities. Despite signifying many therapeutic applications researches indicating quantification or pharmacokinetics of engeletin in biological matrix are still lacking. Here, a simple, sensitive, accurate and reliable ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) approach for the quantification of engeletin in rat plasma was developed and fully validated for the first time. Plasma samples were processed with acetonitrile by a single step protein precipitation and the separation was achieved on a ZORBAX Eclipse Plus C18 Rapid Resolution High Definition column with a gradient acetonitrile-water mobile phase. Quantification of engeletin was carried out by electrospray ionization tandem mass spectrometry in multiple reaction monitoring (MRM) mode with negative ionization. Results revealed that the approach was linearity from 5 to 5000ng/mL (r²=0.9937) and proved to be precise (better than 12.3%) and accurate (-3.3%-5.2%). The developed approach was successfully employed to pharmacokinetic study of engeletin following peroral and intravenous administration to rats. The results of pharmacokinetics demonstrated rapid engeletin absorption (T_max of 15min) after oral administration, extensive distribution after three different dosages and an absolute bioavailability of ∼1.53%. The developed method and pharmacokinetic data can provide a meaningful basis for further studies on engeletin.

Paris polyphylla Suppresses Proliferation and Vasculogenic Mimicry of Human Osteosarcoma Cells and Inhibits Tumor Growth In Vivo

Paris polyphylla, a traditional antipyretic-detoxicate chinese medicinal herb, has been applied extensively in cancer treatments for nearly 2000 years. The purpose of the present study is to evaluate the potential anti-osteosarcoma effects of Paris polyphylla ethanol extract (PPEE) and to investigate its underlying mechanisms. The antiproliferation activity of PPEE was tested on 143B, MG-63, U-2 OS and hFOB1.19 cells using MTT assay. The pro-apoptotic and cell cycle arrest effects of PPEE were confirmed by Hoechst 33342 staining and flow cytometry. The antimigratory, anti-invasive and antivasculogenic mimicry (VM) effects of PPEE were investigated by wound healing, Transwell and 3D culture assays. Mouse xenograft model was used to examine its anti-osteosarcoma efficacy in vivo. Hematologic profiles and hepatorenal functions were evaluated to assess the toxicity of PPEE. PPEE evidently suppressed cell proliferation of 143B, MG-63 and U-2 OS with IC50 values of 10-60[Formula: see text][Formula: see text]g/mL, but showed little cytotoxicity against normal osteoblastic cell. PPEE promoted apoptosis in 143B cell via caspase activation, increased Bax/Bcl-2 ratio and PARP cleavage. It also induced G2/M phase arrest associated with elevated phosphorylation of CDK1, Cdc25C, Chk2 and down-regulation of cyclin B1, CDK1, Cdc25C expression. Additionally, PPEE inhibited 143B cell migration, invasion and VM formation at noncytotoxic concentrations through decreasing the expression of FAK, Mig-7, MMP2 and MMP9. Finally, daily oral administration of PPEE for four weeks exhibits potent antitumor and anti-VM activity in 143B xenograft model with low toxicity. Taken together, these findings demonstrated PPEE possesses anti-osteosarcoma and anti-VM activity in vitro and in vivo, and therefore is a potential candidate for osteosarcoma treatment.

Quantitative determination of gracillin by HPLC-MS/MS after oral administration and its application to a pharmacokinetic study

A sensitive and credible high performance liquid chromatography hyphenated to mass spectrometry (HPLC-MS/MS) was established to quantify the concentration of gracillin in rat plasma. The plasma samples were subjected to a direct protein precipitation process with acetonitrile as a precipitant in a single-step. Ginsenoside Rb1 was selected as an internal standard (IS). The chromatographic separation of analyte and IS were carried out on an Inersil ODS-3 C18 column (250×4.6mm, 5μm) with a binary solvent system containing acetonitrile and 0.1% formic acid in water at a flow rate of 1mLmin(-1) under a gradient elution mode. Mass spectrometric detection was performed on a triple quadrupole tandem mass spectrometer by the multiple reaction monitoring (MRM) mode to examine the precursor-to-daughter ion transitions of 1110.3→948.2 for IS and 886.1→739.9 for gracillin, respectively, in a positive electrospray ionization mode. The calibration curve showed a promising linearity over a concentration range of 0.065-800ngmL(-1) with a better regression coefficient of r(2)=0.9960. The intra- and inter-day precisions (as relative standard deviation) of the assay at three quality control levels were all less than 3.48%, while the intra- and inter-day accuracies (as relative error) ranged from -8.43% to 9.74%, whose data were within the acceptable limits. The mean extraction recoveries of analyte from rat plasma were all more than 74.11%, and no notable matrix effect was observed. Stability experiments revealed that gracillin remained stable throughout the analytical procedure under various stored conditions. The above validated method was successfully used to investigate the pharmacokinetic behaviors of gracillin orally administrated to rats at three proportion doses. The pharmacokinetic analysis would pave the way for understanding the pharmacological actions and provide a meaningful foundation for further development and application in preclinical and clinical use of gracillin in the near future.

Plasma pharmacokinetics, bioavailability and tissue distribution of agnuside following peroral and intravenous administration in mice using liquid chromatography tandem mass spectrometry

Agnuside (AGN), an iridoid glycoside, is the chemotaxonomic marker of the genus Vitex which has gained enormous attention by virtue of its potential health benefits. Regardless of claiming many therapeutic applications reports demonstrating its pharmacokinetics or quantification in biomatrices are lacking. This is the first report which presents a sensitive liquid chromatography coupled to a tandem mass spectrometry (LC-MS/MS) method for the quantification of AGN in mice plasma and various tissues (including liver, intestine, spleen, kidney, heart, lungs and brain). AGN was extracted from the biological samples using protein precipitation followed by liquid-liquid extraction and the separation was achieved on C18 reversed phase column with a mobile phase consisted of 0.1% formic acid in acetonitrile-0.1% formic acid in triple distilled water (92:8, v/v) at a flow rate of 0.7mL/min. The MS/MS detection was performed by electrospray ionization (ESI) using multiple reaction monitoring (MRM) in negative scan mode. The bioanalytical method was found linear over the concentration range of 1-4000ng/mL for plasma and tissue homogenates (r(2)≥0.990). The lower limit of quantitation (LLOQ) for all matrices was 1ng/mL. Intra-day and inter-day variance and accuracy ranged from 90 to 110% and 1-10%, respectively. Matrix effect and recoveries were well within the satisfactory limits. The validated method was applied successfully to measure AGN concentrations in plasma and tissues following intravenous (i.v.) and peroral (p.o.) administration to mice. Maximal AGN concentrations in plasma and tissues were reached within 30-45min. The mean absolute bioavailability (%F) of AGN was∼0.7%. After oral administration, AGN was most abundant in intestine, followed by kidney, liver, spleen, brain, lungs and heart. The identified target tissues of AGN may help in understanding its pharmacological action in vivo.

Anti-lung Cancer Effects of Polyphyllin VI and VII Potentially Correlate with Apoptosis In Vitro and In Vivo

Polyphyllin VI (PVI) and polyphyllin VII (PVII) derived from Paris polyphylla possess anti-cancer activities. However, the mechanisms for the anti-lung cancer effects of PVI and PVII remain poorly understood. In this study, PVI and PVII exhibited inhibitory effects on the proliferation of A549 and NCI-H1299 cells. PVI and PVII induced G2/M cell cycle arrest and triggered apoptosis. PVI and PVII upregulated the tumor suppressor protein p53 and downregulated cyclin B1. The two treatments significantly increased the expression levels of death receptor 3, death receptor 5, Fas, cleaved PARP, and cleaved caspase-3. Furthermore, PVI and PVII significantly inhibited the growth of A549 cells in vivo. The tumor inhibitory rates of PVI were 25.74%, 34.62%, and 40.43% at 2, 3, and 4 mg/kg, respectively, and those of PVII were 25.63%, 41.71%, and 40.41% at 1, 2, and 3 mg/kg, respectively. Finally, PVI and PVII regulated the expression of proteins related to the apoptotic pathway in A549 xenografts. In summary, PVI and PVII exhibited strong inhibitory effects on lung cancer cell growth in vitro and in vivo by inducing G2/M cell cycle arrest and triggering apoptosis.

Pharmacokinetics and tissue distribution of five bufadienolides from the Shexiang Baoxin Pill following oral administration to mice

ETHNOPHARMACOLOGICAL RELEVANCE

Shexiang Baoxin Pill (SBP) is a well-known composite formula of traditional Chinese medicine (TCM), widely used to treat cardiovascular diseases such as angina pectoris and myocardial infarction. Bufadienolides are major active compounds of Venenum Bufonis, which is one of the seven materiamedicas that comprise the Shexiang Baoxin Pill. Previous pharmacokinetics studies of bufadienolides have typically used a single medicinal material delivered to rats. In this study, we have chosen the mouse, a more proper animal model than the rat, to investigate the in vivo pharmacokinetics and tissue distribution of bufadienolides from the Shexiang Baoxin Pill.

MATERIALS AND METHODS

The concentrations of bufadienolides in plasma and tissues were identified using high performance liquid chromatography-tandem mass spectrometry (HPLC-ESI-MS/MS). The samples were prepared by liquid-liquid extraction with ethyl acetate, and the separation of bufadienolides was achieved using an ACQUITY HSS T3 column by gradient elution using water (containing 0.1% formic acid) and acetonitrile as the mobile phase at a flow rate of 0.3 mL/min. The pharmacokinetic parameters were determined using non-compartmental analysis.

RESULTS

The results showed that the five bufadienolides were rapidly absorbed and distributed into the body. The pharmacokinetic curve showed double peaks after oral administration. The major tissue depots for resibufogenin, bufalin, and bufotalin in mice were the intestines, lung and kidney, whereas the major tissue depots of gamabufotalin and arenobufagin were the intestines, liver and kidney.

CONCLUSION

The information gained from this research provides a meaningful insight for the clinical applications of the Shexiang Baoxin Pill.

Simultaneous quantification of five steroid saponins from Dioscorea zingiberensis C.H. Wright in rat plasma by HPLC-MS/MS and its application to the pharmacokinetic studies

A simple, reliable and sensitive high-performance liquid chromatography tandem mass spectrometry method (HPLC-MS/MS) was established for simultaneous analyses of the following 5 steroid saponins in rat plasma after the single dose administration of total steroid saponins extracted from the rhizome of Dioscorea zingiberensis C.H. Wright for the first time. Protodioscin, huangjiangsu A, zingiberensis new saponin, dioscin, and gracillin were quantified using ginsenoside Rb1 as the internal standard (IS). The plasma samples were pretreated by a single step acetonitrile-mediated protein precipitation. The chromatographic separation was performed on an Inersil ODS-3 C18 column (250mm×4.6mm, 5μm) with the mobile phase composed of acetonitrile and water containing 0.1% formic acid under a gradient elution mode at 0.2mLmin(-1) using a microsplit after the eluent from the HPLC apparatus. The quantification was accomplished on a triple quadrupole tandem mass spectrometer using the multiple reaction monitoring (MRM) in the positive ionization mode. The above five analytes were stable under sample storage and preparation conditions applied in the present study. The linearity, precision, accuracy, and recoveries of the analysis confirmed the requirements for quality-control purposes. After validation, this proposed method was successfully adopted to investigate the pharmacokinetic parameters of these five analytes.

Bioanalytical chromatographic method validation according to current regulations, with a special focus on the non-well defined parameters limit of quantification, robustness and matrix effect

Method validation is a mandatory step in bioanalysis, to evaluate the ability of developed methods in providing reliable results for their routine application. Even if some organisations have developed guidelines to define the different parameters to be included in method validation (FDA, EMA); there are still some ambiguous concepts in validation criteria and methodology that need to be clarified. The methodology to calculate fundamental parameters such as the limit of quantification has been defined in several ways without reaching a harmonised definition, which can lead to very different values depending on the applied criterion. Other parameters such as robustness or ruggedness are usually omitted and when defined there is not an established approach to evaluate them. Especially significant is the case of the matrix effect evaluation which is one of the most critical points to be studied in LC-MS methods but has been traditionally overlooked. Due to the increasing importance of bioanalysis this scenario is no longer acceptable and harmonised criteria involving all the concerned parties should be arisen. The objective of this review is thus to discuss and highlight several essential aspects of method validation, focused in bioanalysis. The overall validation process including common validation parameters (selectivity, linearity range, precision, accuracy, stability…) will be reviewed. Furthermore, the most controversial parameters (limit of quantification, robustness and matrix effect) will be carefully studied and the definitions and methodology proposed by the different regulatory bodies will be compared. This review aims to clarify the methodology to be followed in bioanalytical method validation, facilitating this time consuming step.