Rat Plasma Research Articles

N-Stearoylethanolamine Exerts Cardioprotective Effects in Old Rats.

Aging is associated with the slowing down of metabolic processes, diminished physiological processes, changes in hormonal activity and increasing exposure to oxidative stress factors and chronic inflammation. The endocannabinoid system (ECS) is a major signaling network that plays a pro-homeostatic role in the central and peripheral organs of the human body. A class of minor lipids, N-acylethanolamines (NAEs), which do not activate cannabinoid receptors, except for anandamide, but can potentiate the action of endocannabinoids and have a wide spectrum of biological activity and significant adaptogenic potential, belongs to ECS. The results of different studies over the past decades have established the protective effect of NAE on many pathological conditions. This study aimed to investigate the cardioprotective effects of C18:0 NAE- N-stearoylethanolamine (NSE) in aged rats. In this study, we focused on investigating the effects of C18:0 NAE- N-stearoylethanolamine (NSE) on the intensity of oxidative/ nitrosative stress, antioxidant potential, lipoprotein profile and inflammation markers of blood plasma, phospholipid composition and age-related morphological changes of old rat heart tissues. The study was conducted on Sprague Dawley male laboratory rats. The three groups of rats were involved in the study design. The first group consisted of young rats aged 4 months (n=10). The second (n=10) and third (n=10) groups included old rats aged of 18 months. Rats from the third group were administered a per os aqueous suspension of NSE at a dose of 50 mg/kg of body weight daily for 10 days. All groups of rats were kept on a standard vivarium diet. The blood plasma, serum, and heart of rats were used for biochemical and histological analysis. The cardioprotective effect of N-stearoylethanolamine in old rats was established, which was expressed in the normalization of the antioxidant system condition and the level of proinflammatory cytokines, positive modulation of blood plasma and lipoprotein profile, normalization of heart tissue lipid composition, and significant reduction in age-related myocardium morphological changes. The revealed effects of N-stearoylethanolamine can become the basis for developing a new drug for use in complex therapy to improve the quality of life of older people.

An effective LC-MS method for the simultaneous determination of a potential anti-rheumatoid arthritis drug, carboxyamidotriazole, and its major metabolite in rat plasma.

Carboxyamidotriazole (CAI) was previously recognized as a well-tolerated anticancer drug. It has also demonstrated significant anti-inflammatory effects in various cell and animal model experiments, prompting its investigation as a potential treatment for rheumatoid arthritis. In this study, the potential biotransformation metabolites of CAI were identified both in vitro and in vivo. A sensitive, specific, and accurate LC-MS method was developed for the quantitative analysis of CAI and its major metabolite, CAI-OH, in rat plasma. CAI, CAI-OH, and telmisartan (used as an internal standard) were separated using a Zorbax SB C18 column. The mobile phase consisted of water (phase A, containing 0.1% formic acid) and acetonitrile (phase B, containing 0.1% formic acid) at a flow rate of 0.2 mL/min. The analytes were examined using a high-resolution mass spectrometer, with detected mass-to-charge ratios of m/z 424.01293 for CAI, m/z 440.00785 for CAI-OH, and m/z 515.24415 for telmisartan. Good linearity was observed within the range of 10-5000 ng/mL. Both inter- and intra-batch precision (relative standard deviation, %) were below 6%, and the accuracy ranged from 94.9% to 106.1%. The analytes remained stable throughout the entire experimental period. This method was successfully applied in a pharmacokinetic study of CAI following oral administration in rats.

Phytochemical Identification and Anti-Oxidative Stress Effects Study of Cimicifugae Rhizoma Extract and Its Major Component Isoferulic Acid

Background and Objectives: Cimicifugae Rhizoma, also known as ‘Sheng ma’ in Madeiran, is a widely used Chinese herbal medicine that has several pharmacological qualities, one of which is its antioxidant activity. Isoferulic acid, a prominent phenolic compound found in Cimicifugae Rhizoma, has potent antioxidant properties. This study was aimed to comprehensively analyze the components in Cimicifugae Rhizoma and rat plasma to evaluate the in vitro antioxidant and anti-inflammatory properties of Cimicifugae Rhizoma extract and Isoferulic acid as potential candidates for developing herbal formulations targeting podocyte injury in diabetic nephropathy for further clinical utilization. Materials and Methods: UPLC/Q-TOF-MS and HPLC were utilized as analytical tools to identify components of Cimicifugae Rhizoma extract or rat plasma after administrating it. MPC5 cells were cultured with H2O2 and high glucose and subjected to oxidative stress injury. The CXCL12/CXCR4 system plays a crucial role at certain stages of multiple kidney diseases’ injury. Apoptosis-related and target CXCL12/CXCR4/mTOR/Caspase-3 and Cask protein levels were assessed, and the levels of inflammatory-related factors, motility, morphology, ROS level, and apoptosis in podocytes were tested. Results: A total of 82 and 39 components were identified in the Cimicifugae Rhizoma extract and plasma, and Isoferulic acid content was determined as 6.52 mg/g in the Cimicifugae Rhizoma extract. The Cimicifugae Rhizoma extract (1 μg/mL) and Isoferulic acid (10, 25, 50 μM) considerably decreased high glucose and oxidative-stress-mediated toxicity, impaired mobility and adhesion and apoptotic changes in MPC5 cells, and reversed inflammation response. Moreover, the Cimicifugae Rhizoma extract and Isoferulic acid down-regulated Cask, mTOR, and Caspase-3, while significantly blocking the overactivation of CXCL12/CXCR4 in podocytes stimulated by oxidative stress and high glucose. Conclusions: These results indicate that the renal protective mechanism of the Cimicifugae Rhizoma extract and Isoferulic acid on simulating H2O2-induced podocyte injury involves mainly the of CXCL12/CXCR4 pathways and the inactivation of oxidative-stress-mediated apoptotic pathways after comprehensive qualitative and quantitative research by UPLC/Q-TOF-MS and HPLC. These findings provide an important efficacy and ingredient basis for further study on the clinical utilities of Cimicifugae Rhizoma and Isoferulic acid on podocyte and kidney impairment.

Mechanism of Guigan Longmu Decoction in the Treatment of Arrhythmias Based on Network Pharmacology and Untargeted Metabolomics Assays.

Guigan longmu decoction (GGLM), a traditional Chinese medicine compound, has demonstrated efficacy in treating rapid arrhythmia clinically. Nevertheless, its mechanism of action remains elusive. This study aims to elucidate the molecular mechanism underlying the efficacy of GGLM in treating arrhythmia utilizing non-targeted metabolomics, widely-targeted metabolomics, and network pharmacology, subsequently validated through animal experiments. Initially, network pharmacology analysis and widely-targeted metabolomics were performed on GGLM. Subsequent to that, rats were administered GGLM intervention, and nontargeted metabolomics assays were utilized to identify metabolites in rat plasma postadministration. The primary signaling pathways, core targets, and key active ingredients of GGLM influencing arrhythmia were identified. Additionally, to validate the therapeutic efficacy of GGLM on arrhythmia rat models, a rat model of rapid arrhythmia was induced via subcutaneous injection of isoproterenol, and alterations in pertinent pathogenic pathways and proteins in the rat model were assessed through qRT-PCR and Western blot following GGLM administration. The results of network pharmacology showed that 99 active ingredients in GGLM acted on 249 targets and 201 signaling pathways, which may be key to treating arrhythmia. Widelytargeted metabolic quantification analysis detected a total of 448 active ingredients in GGLM, while non-targeted metabolomics identified 279 different metabolites and 10 major metabolic pathways in rats. A comprehensive analysis of the above results revealed that the core key active ingredients of GGLM in treating arrhythmia include calycosin, licochalcone B, glabridin, naringenin, medicarpin, formononetin, quercetin, isoliquiritigenin, and resveratrol. These active ingredients mainly act on the relevant molecules and proteins upstream and downstream of the MAPK pathway to delay the onset of arrhythmia. Animal experimental results showed that the heart rate of rats in the model group increased significantly, and the mRNA and protein expression of p38, MAPK, JNK, ERK, NF-kb, IL-1β, and IL-12 in myocardial tissue also increased significantly. However, after intervention with GGLM, the heart rate of rats in the drug group decreased significantly, while the mRNA and protein expression of p38 MAPK, JNK, ERK1, NF-kb, IL-1β, and IL-12 in myocardial tissue decreased significantly. GGLM, as an adjunctive therapy in traditional Chinese medicine, exhibits favorable therapeutic efficacy against arrhythmia. This can be attributed to the abundant presence of bioactive compounds in the formulation, including verminin, glycyrrhizin B, glabridine, naringenin, ononin, quercetin, isorhamnetin, and kaempferol. The metabolites derived from these active ingredients have the potential to mitigate myocardial inflammation and decelerate heart rate by modulating the expression of proteins associated with the MAPK signaling pathway in vivo.

A validated LC-MS/MS method for simultaneous quantitation of piperacillin, cefazolin, and cefoxitin in rat plasma and twelve tissues

BackgroundThe investigation of drug disposition in tissues is critical to improving dosing strategy and maximizing treatment effectiveness, yet developing a multi-tissue bioanalytical method could be challenging due to the differences among various matrices. Herein, we developed an LC-MS/MS method tailored for the quantitation of piperacillin (PIP), cefazolin (CFZ), and cefoxitin (CFX) in rat plasma and 12 tissues, accompanied by validation data for each matrix according to the FDA and EMA guidelines. ResultsThe method required only a small sample volume (5 μL plasma or 50–100 μL tissue homogenates) and a relatively simple protocol for simultaneous quantitation of PIP, CFZ, and CFX within different biological matrices. Mobile phase A was composed of 5 mM ammonium formate and 0.1 % formic acid in water, while mobile phase B contained 0.1 % formic acid in acetonitrile. The mobile phase was pumped through a Synergi Fusion-RP column equipped with a guard column with a gradient elution program at a 0.3 mL/min flow rate. The mass spectrometer was operated in positive ionization mode (ESI+) using multiple reaction monitoring. SignificanceThe validated method has been successfully applied to quantify PIP, CFZ, and CFX from the plasma and tissue samples collected in a pilot rat study and will further be used in a large pharmacokinetic study. To our knowledge, this is also the first report presenting long-term, freeze-thaw, and autosampler stability data for PIP, CFZ, and CFX in rat plasma and multiple tissues.

Quinolinyl-based multitarget-directed ligands with soluble epoxide hydrolase and fatty acid amide hydrolase inhibitory activities: Synthetic studies and pharmacological evaluations

Simultaneous inhibition of soluble epoxide hydrolase (sEH) and fatty acid amide hydrolase (FAAH) with a single small molecule represents a novel therapeutic approach in treating inflammatory pain, since both targets are involved in pain and inflammation processes. In this study using multi-target directed ligands methodology we designed and synthesized 7 quinolinyl-based dual sEH/FAAH inhibitors, using an optimized microwave-assisted Suzuki-Miyaura coupling reaction and tested their potency in human FAAH and human, rat, and mouse sEH inhibition assays. The structure-activity relationship study showed that quinolinyl moiety is well tolerated in the active sites of both enzymes, yielding several very potent dual sEH/FAAH inhibitors with the IC50 values in the low nanomolar range. The most potent dual inhibitor 4d was further evaluated in stability assay in human and rat plasma where it performed better than the standard Warfarin while in vivo study revealed that 1 mg/kg 4d can inhibit acute inflammatory pain in male rats to a similar degree as the traditional nonsteroidal anti-inflammatory drug ketoprofen (30 mg/kg) after intraperitoneal injection. ADMET prediction studies for this dual inhibitor show favorable pharmacokinetic properties which will guide the future in vivo evaluations.

Pharmacokinetic study and neuropharmacological effects of atractylenolide Ⅲ to improve cognitive impairment via PI3K/AKT/GSK3β pathway in intracerebroventricular-streptozotocin rats

Ethnopharmacological relevanceThe traditional Chinese herbal remedy Atractylodes macrocephala Koidz is renowned for its purported gastrointestinal regulatory properties and immune-enhancing capabilities. Atractylenolide III (ATL III), a prominent bioactive compound in Atractylodes macrocephala Koidz, has demonstrated significant pharmacological activities. However, its impact on neuroinflammation, oxidative stress, and therapeutic potential concerning Alzheimer's disease (AD) remain inadequately investigated.Aim of the study: This study aims to assess the plasma pharmacokinetics of ATL III in Sprague-Dawley (SD) rats and elucidate its neuropharmacological effects on AD via the PI3K/AKT/GSK3β pathway. Through this research, we endeavor to furnish experimental substantiation for the advancement of novel therapeutics centered on ATL III. Materials and methodsThe pharmacokinetic profile of ATL III in SD rat plasma was analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). AD models were induced in SD rats through bilateral intracerebroventricular (ICV) administration of streptozotocin (STZ). ATL III was administered at doses of 0.6 mg/kg, 1.2 mg/kg, and 2.4 mg/kg, while donepezil (1 mg/kg) served as control. Cognitive function assessments were conducted employing behavioral tests including the Morris Water Maze and Novel Object Recognition. Neuronal pathology and histological changes were evaluated through Nissl staining and Hematoxylin-Eosin (HE) staining, respectively. Oxidative stress levels were determined by quantifying malondialdehyde (MDA) content and total superoxide dismutase (T-SOD) activity. Molecular docking analysis was employed to explore the direct binding between ATL III and its relevant targets, followed by validation using Western blot (WB) experiments to assess the expression of p-Tau, PI3K, AKT, GSK3β, and their phosphorylated forms. ResultsWithin the concentration range of 5–500 ng/mL, ATL III demonstrated exceptional linearity (R2 = 0.9991), with a quantification limit of 5 ng/mL. In male SD rats, ATL III exhibited a Tmax of 45 min, a t1/2 of 172.1 min, a Cmax of 1211 ng/L, and an AUC(0-t) of 156031 ng/L*min. Treatment with ATL III significantly attenuated Tau hyperphosphorylation in intracerebroventricular-streptozotocin (ICV-STZ) rats. Furthermore, ATL III administration mitigated neuroinflammation and oxidative stress, as evidenced by reduced Nissl body loss, alleviated histological alterations, decreased MDA content, and enhanced T-SOD activity. Molecular docking analyses revealed strong binding affinity between ATL III and the target genes PI3K, AKT, and GSK3β. Experimental validation corroborated that ATL III stimulated the phosphorylation of PI3K and AKT while reducing the phosphorylation of GSK3β. ConclusionsOur results indicate that ATL III can mitigate Tau protein phosphorylation through modulation of the PI3K/AKT/GSK3β pathway. This attenuation consequently ameliorates neuroinflammation and oxidative stress, leading to enhanced learning and memory abilities in ICV-STZ rats.

Hemay181: A novel SDC (sugar linked drug conjugate) for solid tumors targeting tumor microenvironment.

e15006 Background: Hemay181 is a novel broad-spectrum conjugated cytotoxic drug for treating advanced solid tumours. The drug exerts its inhibitory effect on tumour growth by releasing cytotoxic drug SN-38 in tumour tissues via β-glucuronidase (βGU) metabolism to inhibit the activity of topoisomerase I (TOP1). The water solubility of Hemay181 is increased > 5000-fold compared to SN-38. Hemay181 also binds to plasma albumin to form a macromolecular drug transporter, significantly improving the drug's pharmacokinetics. In addition, βGU has low activity in normal tissues, localised to the lysosomes, but is highly expressed in the hypoxic tumour microenvironment. Methods: In vitro and In Vivo studies showed Hemay181 inhibited growth in 29 human tumour cell lines and 16 human tumor Xenograft models, including colorectal cancer, gastric cancer, triple-negative breast cancer, head and neck cancer, pancreatic cancer, lung cancer, prostate cancer and melanoma. Results: In the absence of βGU, Hemay181 showed significantly weaker inhibitory activity than Hemay181+βGU or no significant inhibitory activity. In these In vitro studies with the addition of βGU, the activity was similar to SN-38, ranging from 3.9 nM to 159 nM. Hemay181 showed tumor selectivity with low activity against two normal human cell lines. The IC50 values of Hemay181 against Chang liver (normal liver cells) and MRC 5 (embryonic lung cells) were 318 nM and 14566 nM under non-enzymatic digestion conditions. In vivo, Hemay181 had significant inhibitory effects on the growth of human colorectal cancer, pancreatic cancer, head and neck cancer, triple-negative breast cancer, lung cancer, liver cancer, ovarian cancer and gastric cancer tumour models. The lowest effective dose of Hemay181 was 1.875mg/kg in the human colon cancer HCT116 model. Within the dose range of 3.75~60 mg/kg, the highest inhibitory rate of the above different tumour models could reach more than 90%. Hemay181 significantly reduced tumour volume compared to irinotecan, which only slowed the tumour growth rates. There was no significant decrease in the body weight of Hemay181 in these studies. In the colon cancer PDX model (CR0029) (30mg/kg), the tumour inhibition rate (TGI) was 78%. At 60mg/kg, in triple-negative breast cancer (BR1458) and non-small cell lung cancer (LU3075) PDX models, a TGI was 97% and 98%, respectively. At 60mg/kg, there was a significant tumour suppressive effect on larger tumours treated with irinotecan, with a reduction of tumour volume. In vitro , 1 μM Hemay181 is stable in CD1 mouse and SD rat plasma, with a minor degree of metabolism in beagle dog, cynomolgus monkey and human plasma. Conclusions: In summary, the novel broad-spectrum anti-tumour drug Hemay181 has the characteristics of high water solubility, tumour-targeting ability, low toxicity and side effects on normal tissues. It is under evaluation in ongoing clinical studies.

Application of newly developed and validated LC-MS/MS method for pharmacokinetic study of adagrasib and pembrolizumab simultaneously in rat plasma

Non-small cell lung cancer (NSCLC) is a significant subtype of lung cancer, and poses a dangerous global threat. One of the current approaches of NSCLC treatment is a combination therapy of adagrasib and pembrolizumab. Accurate monitoring of these drug concentrations in biological fluids is critical for treatment efficacy. Since no method was reported for simultaneous estimation of these drugs, this study focuses on the development of a validated LC-MS/MS bioanalytical method for simultaneous quantification of Adagrasib and Pembrolizumab in rat plasma. The analytes were extracted from the biological matrix through liquid–liquid extraction techniques using acetonitrile as extraction solvent. The analytes were separated on a Waters X-bridge phenyl C18 column, with a mixture of acetonitrile: 0.1 % TFA in water (50: 50 v/v) as mobile phase at an isocratic flow rate of 1.0 mL/min with a runtime of about 5 min. Adagrasib (m/z 605.12 → 201.62), Pembrolizumab (m/z 146.32 → 85.15), and Sotorasib (m/z 561.59 → 218.92) were determined by recording the mass spectra through multiple reaction monitoring in positive mode. The method was validated according to USFDA guidelines. The results demonstrate satisfactory linearity with an r2 value of 0.9998 in the ranges of 40–800 and 10–200 ng/mL, accuracy with mean percentage recovery of 95.22–98.59 % and 96.98–98.57 %, precision indicated with %RSD ranged between 0.39–1.91 % and 0.85–9.03 % for Adagrasib and Pembrolizumab respectively, and other key parameters. The developed method can determine the pharmacokinetic parameters to indicate the efficacy and safety of the drugs, and also can quantify selected drugs simultaneously in biological samples.

LC-MS/MS analysis of didehydrostemofoline from Stemona collinsiae roots extracts in rats plasma and pharmacokinetics profile after oral administration

Stemona collinsiae Craib., Stemonaceae, has been traditionally used as medicinal plants for insecticides, treatment of parasitic worms and various diseases in Southeast Asian countries. Its ethanolic root extract has been postulated for anthelminthic activities which has a potential for development for human gnathostomiasis drug. To investigate the pharmacokinetic profile, liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method for the quantification of didehydrostemofoline in rats' plasma was developed and validated. The chromatographic separation was performed on a C18 column using 1 mM ammonium acetate in water and methanol (50:50, v/v). Tetrahydropalmatine was used as an internal standard. The multiple reaction monitoring mode was used for quantitative analysis. The validated method showed good sensitivity, linearity, precision, and accuracy. The results of stability showed that didehydrostemofoline was stable in the extracted samples in auto-sampler for 24 h and in the plasma samples under room temperature for 24 h, −20 °C for 1 month, and after three freeze-thaw processes. The developed method was applied to the pharmacokinetic study of didehydrostemofoline after oral administration of S. collinsiae root extract. Didehydrostemofoline was rapidly absorbed from the gastrointestinal tract. The time to peak drug concentration was 1.75 ± 0.62 h with maximum drug concentration of 1152.58 ± 271.18 ng/mL. Didehydrostemofoline was rapidly eliminated from the body with terminal half-life of 1.86 ± 0.50 h. Calculated drug clearance of didehydrostemofoline was 96.82 ± 23.51 L/h and volume of distribution was 260.40 ± 96.81 L. The present study provided useful data for understanding drug disposition in the body with dynamic time-course which could be beneficial for further clinical trials.

Simultaneous measurement of COVID-19 treatment drugs (nirmatrelvir and ritonavir) in rat plasma by UPLC-MS/MS and its application to a pharmacokinetic study

PAXLOVID™ (Co-packaging of Nirmatrelvir with Ritonavir) has been approved for the treatment of Coronavirus Disease 2019 (COVID-19). The goal of the experiment was to create an accurate and straightforward analytical method using ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) to simultaneously quantify nirmatrelvir and ritonavir in rat plasma, and to investigate the pharmacokinetic profiles of these drugs in rats. After protein precipitation using acetonitrile, nirmatrelvir, ritonavir, and the internal standard (IS) lopinavir were separated using ultra performance liquid chromatography (UPLC). This separation was achieved with a mobile phase composed of acetonitrile and an aqueous solution of 0.1% formic acid, using a reversed-phase column with a binary gradient elution. Using multiple reaction monitoring (MRM) technology, the analytes were detected in the positive electrospray ionization mode. Favorable linearity was observed in the calibration range of 2.0–10000 ng/mL for nirmatrelvir and 1.0–5000 ng/mL for ritonavir, respectively, within plasma samples. The lower limits of quantification (LLOQ) attained were 2.0 ng/mL for nirmatrelvir and 1.0 ng/mL for ritonavir, respectively. Both drugs demonstrated inter-day and intra-day precision below 15%, with accuracies ranging from −7.6% to 13.2%. Analytes were extracted with recoveries higher than 90.7% and without significant matrix effects. Likewise, the stability was found to meet the requirements of the analytical method under different conditions. This UPLC-MS/MS method, characterized by enabling accurate and precise quantification of nirmatrelvir and ritonavir in plasma, was effectively utilized for in vivo pharmacokinetic studies in rats.

Adherence of Candida albicans to fibrin-clot matrices in a rat model for type 2 diabetes

Individuals with type 2 diabetes are at increased risk for the development of infective endocarditis and septic thrombosis. Adherence to fibrin clot matrices by Candida albicans is the initial step in initiation of the infective processes. Clots made from lean (Fa/fa) and obese (fa/fa) Zucker rat plasma were used to measure adherence of yeast grown at environmental temperature and human body temperature. Adherence to clots by C. albicans was influenced both by source of plasma and temperature of yeast growth. Amphotericin B was effective in diminishing the candidal binding to lean but not obese clots. The degree of fungal surface hydrophobicity did not correlate with adherence to clots. However, Candida adherence to clots from both lean and obese Zucker rats was inhibited by the pretreatment of cells with mannose. These findings indicate that treatment of thrombi-associated candidal infections with ergosterol-targeting drugs e.g., amphotericin B alone in hypercholesterolemic individuals may have decreased clinically efficacy.

Pharmacokinetics of IMM-H012 in rats using ultra-performance liquid chromatography-tandem mass spectrometry.

The present study examined the pharmacokinetics of IMM-H012 in rat plasma, utilizing ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Internal standard cilostazol was employed, and plasma samples were processed using acetonitrile precipitation. A mobile phase (acetonitrile-0.1% formic acid in water) with gradient elution was used to achieve chromatographic separation using a UPLC BEH C18 column. In multiple reaction monitoring mode, electrospray ionization MS/MS was utilized in positive ionization mode. Based on findings, the lower limit of quantification was 2ng/mL, and the linearity of IMM-H012 in rat plasma was found to be acceptable within the range of 2-2000 ng/mL (R2 > 0.995). The intra-day and inter-day precision relative standard deviation was less than 14% of IMM-H012 in rat plasma. The matrix effect was within the range of 102%-107%, and the accuracy ranged from 92% to 113%. Pharmacokinetics of IMM-H012 in rats after oral administration were successfully studied using UPLC-MS/MS.

UPLC-MS/MS analysis of SZJ-1207 in rat plasma, urine, feces and bile for pharmacokinetic studies

AbstractSZJ-1207 is a natural product extracted from Stephanotis mucronata (Blanco) Merr which has significant antidepressant effects in various depression mouse models, without obvious acute toxicity or sedative-hypnotic side effects. The aim of this study was to preliminarily clarify the pharmacokinetic characteristics of SZJ-1207 in rats after a single intragastric and intravenous administration. In this study, sensitive and reliable UPLC-MS/MS quantification methods were established and then successfully applied to the pharmacokinetic study of SZJ-1207 in rats. The linear range of SZJ-1207 were 0.5–400 ng mL−1 in plasma, feaces, bile and 20–4,000 ng mL−1 in urine, respectively (r > 0.99). All methods met the requirements of ICH M10. The results of pharmaconetic study showed that Cmax, AUC(0-t) and AUC(0-∞) had linear relationships with the administered doses in the range of 0.5–4.5 mg kg−1. There was a significant gender difference in the AUC (0-t) of 0.5 and 1.5 mg kg−1 and Cmax of 1.5 mg kg−1 after ig (P < 0.05). The excretion rates of SZJ-1207 were 8.46 ± 4.82% in feces, 1.89 ± 1.08% in urine, and 0.179 ± 0.118% in bile. The oral absolute bioavailability of SZJ-1207 was calculated as 64.64%.

Determination of fraxetin, fraxin and dimethylfraxetin in rat plasma by UPLC-MS/MS

AbstractObjectiveThe levels of fraxetin, fraxin, and dimethylfraxetin in rat plasma to be measured using an ultra-performance liquid chromatography tandem mass-spectrometry (UPLC–MS/MS) technique and applied to their pharmacokinetics and bioavailability.MethodsThe protein precipitation technique was applied to the plasma preparation using acetonitrile and methanol (9:1, v/v). At a flow rate of 0.4 mL min−1, the elution time was 6 min. The mobile phase consisted of acetonitrile-water with 0.1% formic acid, and the chromatographic column was UPLC HSS T3 (50 mm × 2.1 mm, 1.8 μm). Quantitative analysis was conducted using multiple reaction monitoring (MRM) mode and detection was performed using electrospray ionization (ESI) positive ion mode. In each group, six rats were treated with fraxetin, fraxin, and dimethylfraxetin either orally (5 mg kg−1) or intravenously (1 mg kg−1).ResultsThe calibration curves showed good linearity in the range of 2–4,000 ng mL−1, where r was greater than 0.99. The bioavailability of dimethylfraxetin, fraxin, and fraxetin was determinated to be 19.7, 1.4, and 6.0%.ConclusionThe established UPLC-MS/MS method for determining the levels of these three compounds in rat plasma was successfully applied to the pharmacokinetics of dimethylfraxetin, fraxin, and fraxetin, and the bioavailability was calculated.

Comprehensive Analysis of Chemical Ingredients of Waiganfengsha Granule and Absorbed Components in Rat Plasma Based on UHPLC-Q-TOF-MS.

Waiganfengsha Granule, an over-the-counter drug, is commonly used for treating windheat cold and sore throat in clinical settings. However, its material basis of medicinal efficacy is still unclear. In this study, an efficient integrated analytical strategy was established for its chemical and metabolite profiles study. Firstly, to avoid the possible false-positive results of structural elucidation, an in-house component library that contains chemical constituents reported in the literature from the six individual medicines of Waiganfengsha Granule was established. Secondary, mass data post-processing techniques, including precursor ion list and neutral loss filtering, were applied to enhance the identification accuracy. Thirdly, for the rapid characterization of those absorbed components after oral administration in rats, the identified chemical constituents were used as candidate components for the serum analysis. By comparing the retention time and analyzing mass data, the metabolites in rat plasma were identified. As a result, 57 chemical ingredients were identified, including 21 phenolic acids, 9 alkaloids, 2 flavonoids, 5 lignins, 13 saponins, and 7 other compounds. Among these, 12 compounds were unambiguously identified by comparison with reference standards, and 45 were tentatively characterized by analyzing their accurate MS data, MS/MS fragmentation patterns, and also by comparison with those data reported in the literature. Additionally, 46 metabolites were detected and identified in rat plasma. This study is beneficial for understanding the chemical composition and metabolic profiles of Waiganfengsha Granule, and the results obtained might provide a solid basis for further studies on its functional mechanism.

Inhibition of Glycyrrhiza Polysaccharide on Human Cytochrome P450 46A1 in vitro and in vivo: Implications in Treating Neurological Diseases.

Cytochrome P450 (CYP) 46A1, also known as cholesterol 24S-hydroxylase, is essential for maintaining the homeostasis of cholesterol in the brain and serves as a therapeutic target of neurodegenerative disorders and excitatory neurotoxicity. N-methyl-d-aspartate receptor (NMDAR) is a prototypical receptor for the excitatory neurotransmitter glutamate and can be specifically regulated by 24S-hydroxycholesterol (24S-HC). Glycyrrhiza is one of the most widely used herbs with broad clinical applications. It has several pharmacological activities, such as clearing heat and detoxifying, moistening the lung and relieving cough, analgesic, neuroprotective outcomes, and regulating a variety of drug activities. Glycyrrhiza is a commonly used herb for the treatment of epileptic encephalopathy. However, whether glycyrrhiza can interfere with the activity of CYP46A1 remains unknown. This study aimed to investigate the regulating effects of glycyrrhiza polysaccharides (GP) on CYP46A1-mediated cholesterol conversion, as well as in the modulation of related proteins. The effects of glycyrrhiza polysaccharide (GP) on the activity of CYP46A1 were investigated in vivo and in vitro. Moreover, the potential regulatory effects of GP on the expressions of CYP46A1, HMG-CoA reductase (HMGCR), and NMDAR were also detected. The in vitro results demonstrated that glycyrrhiza polysaccharide (GP), as the main water-soluble active component of glycyrrhiza, remarkably inhibited the activity of CYP46A1 in a non-competitive mode with a Ki value of 0.7003 mg/ml. Furthermore, the in vivo experiments verified that GP markedly decreased the contents of 24S-HC in rat plasma and brain tissues as compared to the control. More importantly, the protein expressions of CYP46A1, GluN2A, GluN2B, and HMG-CoA reductase (HMGCR) in rat brains were all downregulated, whereas the mRNA expressions of CYP46A1 and HMGCR were not significantly changed after treatment with GP. GP exhibits a significant inhibitory effect on CYP46A1 activity in vitro and in vivo, and the protein expressions of CYP46A1, HMGCR, and NMDAR are also inhibited by GP, which are of considerable clinical significance for GP's potential therapeutic role in treating neurological diseases.

Structure and pharmacokinetics/pharmacodynamics of the anticoagulant tetradecasaccharide oHG-14 as an intrinsic tenase inhibitor

The intrinsic tenase complex (iXase) is an attractive antithrombotic target to treat or prevent pathological thrombosis with negligible bleeding risk. Fucosylated glycosaminoglycan (FG) is a promising anticoagulant by inhibiting iXase. A depolymerized FG (dHG-5) as an anticoagulant has been approved for clinical trials. Given that dHG-5 is a multi-component drug candidate consisting of a homologous series of oligosaccharides, it is difficult to predict a clear pharmacokinetics. Here, as a major oligosaccharide component, the tetradecasaccharide (oHG-14) was purified from dHG-5 and its structure was defined as L-Fuc3S4S-α(1,3)-L-Δ4,5GlcA-α(1,3)-{D-GalNAc4S6S-β(1,4)-[L-Fuc3S4S-α(1,]3)-D-GlcA-β(1,3)-}3-D-GalNAc4S6S-β(1,4)-[L-Fuc3S4S-α(1,]3)-D-GlcA-ol. oHG-14 showed potent iXase inhibitory activity in vitro and antithrombotic effect in vivo comparable to dHG-5. After single subcutaneous administration of oHG-14 at 8, 14.4 and 32.4 mg/kg to rats, the absolute bioavailability was 71.6 %–80.9 % determined by the validated bioanalytical methods. The maximum concentration (Cmax) was 3.73, 8.07, and 11.95 μg/mL, respectively, and the time reaching Cmax (Tmax) was about 1 h. oHG-14 was mainly excreted by kidney as the parent compound with the elimination kinetics of first-order linear model. Anticoagulant activity of oHG-14 was positively correlated with its concentration in rat plasma. The pharmacokinetics/pharmacodynamics (PK/PD) of oHG-14 is similar to that of dHG-5. This study could provide supportive data for the clinical trial of dHG-5 and further development of pure oligosaccharide as an antithrombotic drug candidate.

Simultaneous determination of multiple components in rat plasma by UPLC-MS/MS for pharmacokinetic studies after oral administration of Pogostemon cablin extract.

Introduction: Pogostemon cablin (PC) is used in traditional Chinese medicine and food, as it exerts pharmacological effects, such as immune-modulatory, antibacterial, antioxidant, antitumor, and antiviral. Currently, the pharmacokinetics (PK) studies of PC mainly focus on individual components. However, research on these individual components cannot reflect the actual PK characteristics of PC after administration. Therefore, the simultaneous determination of multiple components in rat plasma using UPLC-MS/MS was used for the pharmacokinetic study after oral administration of PC extract in this study, providing reference value for the clinical application of PC. Methods: In the present study, a reliable and sensitive ultra-high performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the simultaneous determination of 15 prototype components (vanillic acid, vitexin, verbascoside, isoacteoside, hyperoside, cosmosiin, apigenin, β-rhamnocitrin, acacetin, ombuin, pogostone, pachypodol, vicenin-2, retusin, and diosmetin-7-O-β-D-glucopyranoside) in rat plasma after oral administration of the PC extract. Plasma samples were prepared via protein precipitation using acetonitrile, and icariin was used as the internal standard (IS). Results: The intra-day and inter-day accuracies ranged from -12.0 to 14.3%, and the precision of the analytes was less than 11.3%. The extraction recovery rate of the analytes ranged from 70.6-104.5%, and the matrix effects ranged from 67.4-104.8%. Stability studies proved that the analytes were stable under the tested conditions, with a relative standard deviation lower than 14.1%. Conclusion: The developed method can be applied to evaluate the PK of 15 prototype components in PC extracts of rats after oral administration using UPLC-MS/MS, providing valuable information for the development and clinical safe, effective, and rational use of PC.

Detection and Characterization of the Metabolites of Ciwujianoside B in Rats Based on UPLC-Fusion Lumos Orbitrap Mass Spectrometry.

We previously conducted a systematic study on the metabolic process and products of hederasaponin B in rats. We hypothesized that the sugar chain structures play a key role in the metabolism of triterpenoid saponins. To verify this hypothesis, we conducted metabolic research on ciwujianoside B ascribed to the same sugar chains and a distinct aglycone and compared it with hederasaponin B. Specifically, we collected feces, urine, and plasma of rats after gavage with ciwujianoside B and identified 42 metabolites by UPLC-Fusion Lumos Orbitrap mass spectrometry. Finally, ciwujianoside B metabolism and hederasaponin B metabolism were compared, reaching the following conclusions: (i) more than 40 metabolites were identified in both, with the majority of metabolites identified in feces; (ii) the corresponding metabolic pathways in vivo were basically similar, including deglycosylation, acetylation, hydroxylation, glucuronidation, oxidation, and glycosylation; and (iii) deglycosylation was considered the main metabolic reaction, and its metabolites accounted for approximately 50% of all metabolites. Overall, this study provides a foundation for further research on the metabolism of triterpenoid saponins.