A selective HPLC-MS/MS method for quantification of SND-117 in rat plasma and its application to a pharmacokinetic study

Investigation of preclinical pharmacokinetics of N-demethylsinomenine, a potential novel analgesic candidate, using an UPLC-MS/MS quantification method

N- Demethylsinomenine (NDSM), the in vivo demethylated metabolite of sinomenine, has exhibited antinociceptive efficacy against various pain models and may become a novel drug candidate for pain management. However, no reported analytical method for quantification of N- Demethylsinomenine in a biological matrix is currently available, and the pharmacokinetic properties of N- Demethylsinomenine are unknown. In the present study, an ultra-high performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method for quantification of N- Demethylsinomenine in rat plasma was developed and utilized to examine the preclinical pharmacokinetic profiles of N- Demethylsinomenine. The liquid-liquid extraction using ethyl acetate as the extractant was selected to treat rat plasma samples. The mixture of 25% aqueous phase (0.35% acetic acid-10 mM ammonium acetate buffer) and 75% organic phase (acetonitrile) was chosen as the mobile phases flowing on a ZORBAX C18 column to perform the chromatographic separation. After a 6-min rapid elution, NDSM and its internal standard (IS), metronidazole, were separated successfully. The ion pairs of 316/239 and 172/128 were captured for detecting N- Demethylsinomenine and IS, respectively, using multiple reaction monitoring (MRM) under a positive electrospray ionization (ESI) mode in this mass spectrometry analysis. The standard curve met linear requirements within the concentration range from 3 to 1000 ng/mL, and the lower limit of quantification (LLOQ) was 3 ng/mL. The method was evaluated regarding precision, accuracy, recovery, matrix effect, and stability, and all the results met the criteria presented in the guidelines for validation of biological analysis method. Then the pharmacokinetic profiles of N- Demethylsinomenine in rat plasma were characterized using this validated UPLC-MS/MS method. N- Demethylsinomenine exhibited the feature of linear pharmacokinetics after intravenous (i.v.) or intragastric (i.g.) administration in rats. After i. v. bolus at three dosage levels (0.5, 1, and 2 mg/kg), N- Demethylsinomenine showed the profiles of rapid elimination with mean half-life (T_1/2Z) of 1.55-1.73 h, and extensive tissue distribution with volume of distribution (V_Z) of 5.62-8.07 L/kg. After i. g. administration at three dosage levels (10, 20, and 40 mg/kg), N- Demethylsinomenine showed the consistent peak time (T_max) of 3 h and the mean absolute bioavailability of N- Demethylsinomenine was 30.46%. These pharmacokinetics findings will aid in future drug development decisions of N- Demethylsinomenine as a potential candidate for pain analgesia.

Potential Advantages of Bioactive Compounds Extracted From Traditional Chinese Medicine to Inhibit Bone Destructions in Rheumatoid Arthritis

Bone destruction is an important pathological feature of rheumatoid arthritis (RA), which finally leads to the serious decline of life quality in RA patients. Bone metabolism imbalance is the principal factor of bone destruction in RA, which is manifested by excessive osteoclast-mediated bone resorption and inadequate osteoblast-mediated bone formation. Although current drugs alleviate the process of bone destruction to a certain extent, there are still many deficiencies. Recent studies have shown that traditional Chinese medicine (TCM) could effectively suppress bone destruction of RA. Some bioactive compounds from TCM have shown good effect on inhibiting osteoclast differentiation and promoting osteoblast proliferation. This article reviews the research progress of bioactive compounds exacted from TCM in inhibiting bone destruction of RA, so as to provide references for further clinical and scientific research.

Pharmacokinetics and Metabolism Research of Shenkang Injection in Rats Based on UHPLC-MS/MS and UHPLC-Q-Orbitrap HRMS

Purpose

Shenkang injection, a traditional Chinese herbal prescription, had been widely used in renal disease due to its perfect curative effect. In this research, a novel, sensitive, accurate and rapid liquid chromatography-tandem mass spectrometric method was developed to simultaneously detect the seven active ingredients in rat plasma of Shenkang injection and investigate its pharmacokinetic behaviors with metabolism profiling meanwhile.

Methods

For accurate pharmacokinetic quantitation, a WATERS ACQUITY UPLC^® BEH C18 column was used to perform a separation and acetonitrile-water (0.1% formic acid) was selected as mobile phase for gradient elution with a flow rate of 0.20 mL/min. A heated electrospray ionization with selective reaction monitoring mode was used to monitor the precursor-product ion transitions for all the analytes and IS.

Results

They all showed good linearity over a wide concentration range (r>0.996 3) and the lower limit of quantification (LLOQ) was 0.1–1.0 ng/mL for analytes. The validation parameters were all within the acceptable limits. Furthermore, for metabolism profiling study, metabolites of the seven ingredients were identified from the rat plasma based on the accurate mass and fragment ions. The metabolic pathways mainly focus on reduction, dehydration and conjugation.

Conclusion

This study provided an overview of disposition of Shenkang injection, which is highly instructive for better understanding the effectiveness and toxicity of this drug.

Assessment of a developed HPLC-MS/MS approach for determining plasma eupatorin in rats and its application in pharmacokinetics analysis

Eupatorin, a bioactive compound extracted from Java tea (Orthosiphon stamineus), possesses potent anti-cancer, anti-inflammatory and vasodilation activities. To date, no pharmacokinetics studies on eupatorin have yet been performed. Here, we established and validated a sensitive and selective LC-MS/MS (liquid chromatography-tandem mass spectrometry) approach for determining plasma eupatorin in rats. Chromatographic fractionation was conducted on a Wonda Cract ODS-2 C18 Column (4.6 mm × 150 mm, 5 μm) with a mobile phase containing aqueous 0.1% formic acid and acetonitrile using a flow rate of 0.8 ml min⁻¹. In multiple reaction monitoring mode, precursor-to-product ion transitions for quantification of eupatorin and the internal standard were set at 343.1 → 328.1 and 252.0 → 155.9, respectively. The intra- and inter-day precision and accuracy were found to be below 6.72% and within ±8.26% in rat plasma, respectively. Meanwhile, all values of the matrix effect, recovery and stability were within the accepted ranges. Furthermore, we carried out the pharmacokinetic analysis using the developed method. The pharmacokinetic study revealed that while the C_max (maximum plasma concentration) of eupatorin and time for reaching the C_max (T_max) were 974.886 ± 293.898 μg L⁻¹ and 0.25 h, respectively, the half-life was 0.353 ± 0.026 h. This study will be of great significance to the research on the pharmacology, clinical pharmacy and drug action mechanism of eupatorin.

Eupatorin, a bioactive compound extracted from Java tea (Orthosiphon stamineus), possesses potent anti-cancer, anti-inflammatory and vasodilation activities.

UPLC-QTOF-MS Identification of the Chemical Constituents in Rat Plasma and Urine after Oral Administration of Rubia cordifolia L. Extract

An effective ultra-performance liquid chromatography coupled with the quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF/MS) method was developed for analysing the chemical constituents in rat plasma and urine after the oral administration of Rubia cordifolia L. extract. Under the optimized conditions, nine of 11 prototypes in rat plasma and four prototypes in urine were identified or characterized by comparing the retention time, accurate mass, fragmentation patterns, reference compounds, and literature data. In total, six metabolites, including alizarin-1-O-β-glucuronide, alizarin-2-O-β-glucuronide, alizarin-1-O-sulfation, alizarin-2-O-sulfation, purpurin-1-O-β-glucuronide, and purpurin-3-O-β-glucuronide, were identified in rat plasma, which were confirmed by lavaging standard solutions. Purpurin was found to be able to be transformed into alizarin based on the results in which alizarin was detected in rat plasma after the oral administration of a purpurin solution. In total, four metabolites were found in rat urine, but their chemical structures were not confirmed. The results indicate that the metabolic pathway of alizarin involves glucuronidation and sulfation, with the purpurins having undergone glucuronidation. The components absorbed into the blood, and the metabolites have the opportunity to become bioactive constituents. The experimental results would supply a helpful chemical basis for further research on the mechanism of actions of Rubia cordifolia L.