Determination of sinomenine in human plasma by HPLC/ESI/ion trap mass spectrum

Sinomenine hydrochloride ameliorates dextran sulfate sodium-induced colitis in mice by modulating the gut microbiota composition whilst suppressing the activation of the NLRP3 inflammasome

Sinomenine is a pure alkaloid that can be isolated from the root of Sinomenium acutum and has been found to exert anti-inflammatory and immunosuppressive effects. The present study investigated the effects of sinomenine hydrochloride (SIN) on inflammation and the gut microbiota composition in the colon of mouse models of dextran sulfate sodium (DSS)-induced colitis. DSS-induced mice colitis was established by treating the mice with drinking water containing 3% (w/v) DSS for 7 days. The disease activity index of each mouse was calculated on a daily basis. All mice were sacrificed on day 11, then the weight of their spleen and length of their colons were measured. The histological analysis was measured by hematoxylin-eosin staining. Oral administration of SIN (100 mg/kg/day) attenuated the DSS-induced increases in the disease activity indices and spleen indices, DSS-induced shortening of the colon length and histological damage. In addition, reverse transcription-quantitative PCR data showed that SIN treatment effectively regulated the expression of inflammatory mediators, specifically by suppressing the expression of proinflammatory gene (TNF-α, IL-6 and inducible nitric oxide synthase) whilst increasing those associated with inhibiting inflammation (IL-10 and arginine 1). Gut microbiota analysis was conducted using 16S ribosomal DNA sequencing. The results revealed that SIN improved bacterial community homeostasis and diversity, which were damaged by DSS. Furthermore, western blotting showed that the activation of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome was markedly suppressed by SIN treatment. In conclusion, these results indicated that SIN may ameliorate experimental colitis by modulating the gut microbiota composition and suppressing the activation of the NLRP3 inflammasome in mice. Overall, these findings suggested a broad protective effect of SIN in treating inflammatory gut diseases, including ulcerative colitis.

Metabolic mechanism and anti-inflammation effects of sinomenine and its major metabolites N-demethylsinomenine and sinomenine-N-oxide

AIMS

Sinomenine (SIN) is clinically used as an anti-rheumatic drug. However, the metabolic and pharmacological mechanisms of SIN combined with its metabolites are unclear. This study aims to explore the cyclic metabolic mechanism of SIN, the anti-inflammation effects of SIN and its major metabolites (N-demethylsinomenine (DS) and sinomenine-N-oxide (SNO)), and the oxidation property of SNO.

MATERIALS AND METHODS

SIN was administrated to rats via gavage. Qishe pills (a SIN-containing drug) were orally administrated to humans. The bio-samples were collected to identify SIN's metabolites. Enzymatic and non-enzymatic incubations were used to reveal SIN's metabolic mechanism. Impacts of SIN, SNO and DS on the inflammation-related cytokine's levels and nuclear translocation of NF-κB were evaluated in LPS-induced Raw264.7 cells. ROS induced by SNO (10 μM) was also assessed.

KEY FINDINGS

CYP3A4 and ROS predominantly mediated the formation of SNO, and CYP3A4 and CYP2C19 primarily mediated the formation of DS. Noteworthily, SNO underwent N-oxide reduction both enzymatically, by xanthine oxidase (XOD), and non-enzymatically, by ferrous ion and heme moiety. The levels of IL-6 and TNF-α and nuclear translocation of NF-κB were ameliorated after pretreatment of SIN in LPS-induced Raw264.7 cells, while limited attenuations were observed after pretreatment of DS (SNO) even at 200 μM. In contrast, SNO induced ROS production.

SIGNIFICANCE

This study elucidated that SIN underwent both enzymatic and non-enzymatic cyclic metabolism and worked as the predominant anti-inflammation compound, while SNO induced ROS production, suggesting more studies of SIN combined with SNO and DS are necessary in case of DDI and potential toxicities.

Evaluation of pharmacokinetics and pharmaco-dynamics of sinomenine-hyaluronic acid conjugate after intra-articular administration for osteoarthritis treatment

Objectives

Intra-articular injection of sinomenine (SN) is an effective treatment method for knee osteoarthritis (OA), however, SN could be eliminated quickly in vivo. To extend the residence time of SN in the joint cavity, the SN-hyaluronic acid (HA) conjugate was prepared previously. This study was performed to evaluate the pharmacokinetics and pharmacodynamics of SN-HA conjugate after intra-articular administration for the treatment of OA.

Methods

A high performance liquid chromatography-mass spectrometry (HPLC-MS/MS) method was established to determine the SN content in rat synovial fluid. One hundred and twenty rats were randomly divided into two groups, the SN-HA group and SN group. The concentration of SN in articular cavity washings was determined by HPLC-MS/MS. The protective effect on the cartilage was evaluated by histological evaluation in a model of papain induced rabbit knee osteoarthritis.

Results

The method was validated with respect to sensitivity, specificity, linearity, precision, accuracy and especially the stability of analytes under various conditions, and was successfully applied in evaluating the pharmacokinetic profiles of SN in the joint cavity. Compared to the SN injection, the drug exposure in joint cavity was significantly increased following SN-HA injection administration, and AUC(0-12h) was 2.9 times of SN injection, mean residence time (MRT) was 1.88 times of SN injection. In the pharmacodynamic study, there was no significant difference between the SN-HA twice-treated group and SH/HA five-times mixture-treated group.

Conclusion

The local bioavailability of SN in joint cavity was improved significantly after conjugated with HA. The SN-HA conjugate showed good synergism effect of OA inhibition. The results indicated that the SN-HA conjugate seemed to be an effective therapeutic means for the treatment of OA.

Trace Analysis of Sinomenine Hydrochloride Using CdTe/CdS Quantum Dots-enhanced Chemiluminescence

A novel flow-injection chemiluminescence (FI-CL) method was described for the determination of sinomenine hydrochloride (SIN). The method was based on the inhibitory effect of SIN on the CL reaction of luminol and K3Fe(CN)6 in an alkaline solution, which was sensitized by CdTe/CdS quantum dots (QDs). Under the optimized conditions, the linear range for the determination of SIN was 1.0 × 10(-8) to 1.4 × 10(-6) mol/L. The detection limit was 7.5 × 10(-9) mol/L, and the relative standard deviation was 2.47% (n = 11). The current CL method was applied to determine SIN in pharmaceutical formulations and biological fluids with satisfactory results. The possible CL reaction mechanism was discussed briefly.

An ultra-high performance liquid chromatographic-tandem mass spectrometric method for the determination of sinomenine in human plasma after transdermal delivery of the zhengqing fengtongning injection

A sensitive, precise and selective ultra-high performance liquid chromatography method coupled with triple-quadrupole mass spectrometry was developed and validated for the determination of trace amounts of sinomenine (ng/mL) in minute volumes of human plasma. Fifty microliter plasma samples were precipitated using methanol to extract sinomenine. Separation was carried out on a C18 column with a water and acetonitrile mobile phase gradient with formic acid as an additive. The mass spectrometry data were obtained in the positive ion mode, and the transition of multiple reactions was monitored at m/z 330.2→181.0 for sinomenine quantification. The working assay range for sinomenine was linear from 0.1173 to 15.02 ng/mL with the lower limit of quantification of 0.1173 ng/mL. The precision and accuracy of the method was less than 15% in intra-day and inter-day experiments with a matrix effect of less than 6.5%. After validation, the quantitative method was applied to analyze sinomenine levels in human plasma after transdermal delivery of the Zhengqing Fengtongning Injection. The results showed that some samples contained sinomenine within the concentration range 0.4131-4.407 ng/mL.

HPLC and LC-MS analysis of sinomenine and its application in pharmacokinetic studies in rats

AIM

To improve and validate analytical methods based on HPLC and liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for the quantitative measurement of sinomenine in rat plasma and brain tissue.

METHODS

The separation of analytes and the internal standard (IS), chloramphenicol, was performed on an Agilent TC-C18 column (250×4.6 mm, 5 μm). Blood samples were measured with a Surveyor photodiode array (PDA) detector at a wavelength of 263 nm. The LCQ DECA XP(Plus) mass spectrometer was operated in the multiple reactions monitoring mode using positive electrospray ionization, and the transition from the precursor ion (m/z 279) to the product ion (m/z 224) for sinomenine was measured in brain tissue.

RESULTS

Measurements were linear over the concentration range of 0.1-100 μg/mL for sinomenine in plasma and over the range of 0.01-5.00 μg/g for sinomenine in brain tissue. The intra- and inter-day variabilities were less than 10% of the relative standard deviation (RSD), and the extraction and recovery of sinomenine was 72.48%-80.26% from plasma and 73.75%-80.26% from brain tissue. The limit of quantification (LOQ) was 0.1 μg/mL for plasma, and 0.01 μg/g for brain tissue. Identification of sinomenine was reproducible at 0.5, 5, and 50 μg/mL in the plasma and at 0.05, 0.50, and 2.00 μg/g in brain tissue. The concentration of sinomenine measured in brain tissue after a single ip dose had a neuroprotective effect on H₂O₂-induced injury in PC12 cells in vitro.

CONCLUSION

Our methods offered a sensitivity within a wide linear concentration range for sinomenine. These methods were successfully applied to evaluate sinomenine pharmacokinetics over time in rat brain tissue after a single ip dose of 30 mg/kg.

Determination of sinomenine in Sinomenium acutum by capillary electrophoresis with electrochemiluminescence detection

A Ru(bpy)(3)(2+)-based electrochemiluminescence (ECL) detection coupled with capillary electrophoresis (CE) has been established for the determination of sinomenine for the first time. Optimum separation was achieved with a fused-silica capillary column (50 cm x 25 microm i.d.) and a background electrolyte of 50 mM sodium phosphate (pH 5.0) at a separation voltage of 15 kV. The content of sinomenine was detected by ECL at the detection voltage of 1.15 V (versus Ag/AgCl) with 5 mM Ru(bpy)(3)(2+) in 75 mM phosphate solution (pH 8.0) when a chemically modified platinum electrode by europium(III)-doped prussian blue analogue (Eu-PB) was used as a working electrode. Under the optimized conditions, the ECL intensity was in proportion to sinomenine concentration in the range from 0.01 to 1.0 microg mL(-1) with a detection limit of 2.0 ng mL(-1) (3sigma). The relative standard derivations of migration time and ECL intensity were 0.93 and 1.11%, respectively. The level of sinomenine in Sinomenium acutum Rehd. et Wils was easily determined with recoveries between 98.6 and 102.7%.

Pharmacokinetic study of free-form sinomenine in rat skin by microdialysis coupled with liquid chromatography–electrospray mass spectrometry

Sinomenine (7,8-didehydro-4-hydroxy-3,7-dimethoxy-17-methylmorphinan-6-one) is a pure alkaloid extracted from the Chinese medical plant. In this report a liquid chromatography-electrospray mass spectrometry (LC-ESI-MS) method with in vivo microdialysis for the pharmacokinetic study of free-form sinomenine in rat skin has been developed. A microdialysis probe was surgically implanted into the subcutaneous tissue of the rats and an isotonic phosphate buffer (PBS) was used as the perfusion medium. Samples were collected and then analyzed off-line by LC-ESI-MS. The chromatographic separation was achieved within 4.2 min by using a narrow-bore Xterra C(18) column (2.1 x 150 mm, 5 microm) with acetonitrile-(10 mmol/L ammonium acetate buffer, 0.1% acetic acid) (15:85, v/v). Ion signal m/z 330.1 for sinomenine was measured in the positive mode. Linearity was established for the range of concentrations of 2.0-10000.0 ng/mL with a coefficient of determination (r) of 0.9989. The intra- and inter-day reproducibility of the present method was better than 6%. The lower limit of quantification (LLOQ) was 1.0 ng/mL. The proposed method described provides more authentic information on pharmacokinetics and metabolism at the site of action by using the coupling of microdialysis to LC-ESI-MS technique than the traditional sampling methods.