Andrographis paniculata Formulations: Impact on Diterpene Lactone Oral Bioavailability.

Diterpene lactones have been identified as active compounds in several medicinal plants, including Andrographis paniculata (Burm. f.) Nees, which is a medicinal plant that has been used for centuries across the world. Andrographolide is the major diterpene from A. paniculata and the main bioactive constituent of this species. The effectiveness of diterpenes can be affected by factors that limit their oral bioavailability, such as their poor water solubility, slow dissolution rates, low gastrointestinal absorption, high chemical and metabolic instability, and rapid excretion. In this context, the purpose of the present review is to compile and compare literature data on the bioavailability of diterpene lactones from A. paniculata after oral administration in medicinal plant extracts or in their free forms and to highlight strategies that have been used to improve their oral bioavailability. Considering that medicinal plant extracts are commonly used as dried powder that is reconstituted in water before oral administration, novel pharmaceutical formulation strategies that are used to overcome difficulties with diterpene solubility are also compiled in this review. The use of self-microemulsifying drug delivery systems is a good strategy to enhance the dissolution and consequently the bioavailability of andrographolide after oral administration of A. paniculata extract formulations. On the other hand, herbosome technology, pH-sensitive nanoparticles, nanosuspensions, nanoemulsions, nanocrystal suspensions, nanocrystal-based solid dispersions, and solid dispersion systems are useful to formulate andrographolide in its free form and increase its oral bioavailability. The use of a suitable andrographolide delivery system is essential to achieve its therapeutic potential.

Natural Dibenzo-α-Pyrones: Friends or Foes?

Natural dibenzo-α-pyrones (DAPs) can be viewed from two opposite angles. From one angle, the gastrointestinal metabolites urolithins are regarded as beneficial, while from the other, the emerging mycotoxin alternariol and related fungal metabolites are evaluated critically with regards to potential hazardous effects. Thus, the important question is: can the structural characteristics of DAP subgroups be held responsible for distinct bioactivity patterns? If not, certain toxicological and/or pharmacological aspects of natural DAPs might yet await elucidation. Thus, this review focuses on comparing published data on the two groups of natural DAPs regarding both adverse and beneficial effects on human health. Literature on genotoxic, estrogenic, endocrine-disruptive effects, as well as on the induction of the cellular anti-oxidative defense system, anti-inflammatory properties, the inhibition of kinases, the activation of mitophagy and the induction of autophagy, is gathered and critically reviewed. Indeed, comparing published data suggests similar bioactivity profiles of alternariol and urolithin A. Thus, the current stratification into hazardous Alternaria toxins and healthy urolithins seems debatable. An extrapolation of bioactivities to the other DAP sub-class could serve as a promising base for further research. Conclusively, urolithins should be further evaluated toward high-dose toxicity, while alternariol derivatives could be promising chemicals for the development of therapeutics.

Afidopyropen: Challenges and impact of a toxicokinetic study designed to identify a point of inflection from dose-proportionality.

Afidopyropen is an insecticide that acts as a transient receptor potential vanilloid subtype (TRPV) channel modulator in chordotonal organs of target insects and has been assessed for a wide range of toxicity endpoints including chronic toxicity and carcinogenicity in rats and mice. The current study evaluates the toxicokinetic properties of afidopyropen and its plasma metabolites in rats at dose levels where the pharmacokinetics (PK) are linear and nonlinear in an attempt to identify a point of inflection. Based on the results of this study and depending on the analysis method used, the kinetically derived maximum dose (KMD) is estimated to be between 2.5 and 12.5 mg/kg bw/d with linearity observed at doses below 2.5 mg/kg bw/d. A defined point of inflection could not be determined. These data demonstrate that consideration of PK is critical for improving the dose-selection in toxicity studies as well as to enhance human relevance of the interpretation of animal toxicity studies. The study also demonstrates the technical difficulty in obtaining a defined point of inflection from in vivo PK data.

Constructing slow-release formulations of herbicide metribuzin using its co-extrusion with biodegradable polyester poly-ε-caprolactone.

Different technologies to prepare long term pesticide forms include polymer coating, preparing composites and encapsulating pesticides in nanoparticles. A simple and low-cost method was proposed to obtain slow-release formulations by co-extrusion of a pesticide with a biodegradable polymer at a temperature above the melting points of both components. A herbicide metribuzin and low-melting polyester poly-ε-caprolactone were chosen for this work. Formulations containing 10%, 20%, and 40% herbicide were prepared. During 7 days of their exposition in water, it was released from 81% to 96% of initially loaded metribuzin; the highest release was detected for 40%-loaded forms. Biodegradation of the constructs and pesticide release were further studied in the model soil. Degradation rates of the specimens increased with an increase in pesticide content, from 9% to 20% over 14 weeks for the 10%/20%-loaded and the 40%-loaded specimens, respectively. The release of metribuzin reached, respectively, 37-38% and 55%. The herbicide content in soil was lower due to its partial degradation in soil; it reached 23-25% and 33%, respectively, from initially loaded into the polymer matrix. Release kinetics of metribuzin in water as in soil best fitted the First-order model. The used approach is promising for obtaining long-term release formulations for soil applications.

Atractylenolide I enhances responsiveness to immune checkpoint blockade therapy by activating tumor antigen presentation.

One of the primary mechanisms of tumor cell immune evasion is the loss of antigenicity, which arises due to lack of immunogenic tumor antigens as well as dysregulation of the antigen processing machinery. In a screen for small-molecule compounds from herbal medicine that potentiate T cell-mediated cytotoxicity, we identified atractylenolide I (ATT-I), which substantially promotes tumor antigen presentation of both human and mouse colorectal cancer (CRC) cells and thereby enhances the cytotoxic response of CD8+ T cells. Cellular thermal shift assay (CETSA) with multiplexed quantitative mass spectrometry identified the proteasome 26S subunit non-ATPase 4 (PSMD4), an essential component of the immunoproteasome complex, as a primary target protein of ATT-I. Binding of ATT-I with PSMD4 augments the antigen-processing activity of immunoproteasome, leading to enhanced MHC-I-mediated antigen presentation on cancer cells. In syngeneic mouse CRC models and human patient-derived CRC organoid models, ATT-I treatment promotes the cytotoxicity of CD8+ T cells and thus profoundly enhances the efficacy of immune checkpoint blockade therapy. Collectively, we show here that targeting the function of immunoproteasome with ATT-I promotes tumor antigen presentation and empowers T cell cytotoxicity, thus elevating the tumor response to immunotherapy.

Preclinical safety evaluation of nafithromycin (WCK 4873) with emphasis on liver safety in rat and dog.

Ketolide antibiotics are known to cause hepatic injury. Nafithromycin, a novel lactone ketolide was therefore assessed for hepatic safety through range of preclinical in vitro (metabolic stability, CYP inhibition/induction assays) and in vivo (mass balance and repeat dose toxicity) studies. Repeat-dose toxicity studies in rat and dog revealed that nafithromycin did not cause adverse hematological, biochemical and histopathological changes suggestive of systemic or hepatobiliary safety concern at exposures 3-8 fold higher than targeted therapeutic exposures. The only histological finding noticed was reversible phospholipidosis, mainly in lung and lymphoid organs but not in liver, indicating lower nafithromycin accumulation in liver. This observation was corroborated with lack of biologically relevant elevation of hepatic enzymes linked to hepatic injury. In vitro studies showed that nafithromycin undergoes moderate CYP3A mediated metabolism. Unlike other ketolides, nafithromycin and its metabolites showed weak inhibition of CYP3A isoform and lacked CYP2D6 inhibition. Due to hydrophilic nature, nafithromycin in addition to hepatic clearance is also eliminated unchanged by kidneys in significant amount, thereby minimizing hepatic burden. Based on the scientifically integrated evidences such as moderate metabolism, weak CYP inhibition, lack of CYP induction, minimal accumulation in liver, nafithromycin showed promising hepatic safety profile suitable for its intended community-based usage.

Rapid Profiling of the Marker Components in Artemisia annua L. and their Metabolites in Rats Using an Improved Liquid Chromatography-tandem Highresolution Mass Spectrometry-based Technology.

BACKGROUND: As parasite resistance to the main artemisinin drugs has emerged in Southern Asia, the traditional herb Artemisia annua L. (AAL) from which artemisinin (QHS) isolated was found to overcome resistance to QHS. However the component and metabolite profiles of AAL remain unclear. OBJECTIVE: In this study, component profiling of marker compounds in AAL (amorphane sesquiterpene lactones and flavonoids) was performed and their subsequent metabolism was investigated in rats. METHODS: For efficient component classification and structural characterization, an improved liquid chromatography- tandem high-resolution mass spectrometry (HRMS)-based analytical strategy was applied, i.e., background subtraction (BS) followed by ring-double-bond (RDB) filter in tandem with repeated BS processing. Structures of detected components/metabolites were characterized based on integrated information including their HRMSn patterns, RDB values, the established component/metabolite network, the biosynthesis pathways of AAL, and/or NMR data. RESULTS: A total of 38 amorphane sesquiterpene lactones and 35 flavonoids were found in AAL as prototype compounds, among which 26 components were previously undescribed. Major compounds were identified by comparing them with reference standards. Among 73 AAL prototypes administered, 38 were absorbed in the circulation as the prototype. Moreover, 20 metabolites of amorphane sesquiterpene lactones and 10 metabolites of flavonoids were detected in rats. The major metabolic pathways included oxidation, methylation, glucuronidation and sulfation. CONCLUSION: The component and metabolite network were established for marker components in AAL, which will be valuable to understand the synergistic antimalarial potency of QHS in A. annua L. The analytical strategy can also be applied to other herbal medicines.

ADMET profile and virtual screening of plant and microbial natural metabolites as SARS-CoV-2 S1 glycoprotein receptor binding domain and main protease inhibitors.

In an attempt to search for selective inhibitors against the SARS-CoV-2 which caused devastating of lives and livelihoods across the globe, 415 natural metabolites isolated from several plants, fungi and bacteria, belonging to different classes, were investigated. The drug metabolism and safety profiles were computed in silico and the results showed seven compounds namely fusaric acid, jasmonic acid, jasmonic acid methyl ester, putaminoxin, putaminoxin B and D, and stagonolide K were predicted to having considerable absorption, metabolism, distribution and excretion parameters (ADME) and safety indices. Molecular docking against the receptor binding domain (RBD) of spike glycoprotein (S1) and the main protease (Mpro) exposed the compounds having better binding affinity to main protease as compared to the S1 receptor binding domain. The docking results were compared to an antiviral drug penciclovir reportedly of clinical significance in treating the SARS-CoV-2 infected patients. The results demonstrated the test compounds jasmonic acid, putaminoxins B and D bound to the HIS-CYS catalytic dyad as well as to other residues within the MPro active site with much greater affinity than penciclovir. The findings of the study suggest that these compounds could be explored as potential SARS-CoV-2 inhibitors, and could further be combined with the experimental investigations to develop effective therapeutics to deal with the present pandemic.

Toxicological and pharmacokinetic analysis at therapeutic dose of SRS27, an investigational anti-asthma agent.

SRS27, an andrographolide analogue, had been proven to have therapeutic properties at a dose of 3 mg/kg in both in vitro and in vivo asthma models of our previous study. The present study focuses on the pharmacokinetic and toxicity profile of this compound to provide further evidence for the development of this compound as an anti-asthma agent. A simple pharmacokinetic study was performed in female BALB/c mice to measure blood plasma concentration of the compound at therapeutic dose. At a single dose of 3 mg/kg, SRS27 had a relatively short half-life but was able to achieve a concentration range of 13-19 µM that is related to its in vitro bioactivities. With regard to toxicity profile, SRS27 appears to be safe, as no histopathological changes were observed in the liver, kidneys and ovaries of SRS27-treated female BALB/c mice. In addition, there was no significant change in the mean body weight and organ weight of the animals in the SRS27-treated groups compared with the vehicle-treated control group at the end of the treatment. This fully supports the absence of any significant changes in peripheral blood leukocyte counts of SRS27-treated mice. Rewardingly, this acute toxicity study also revealed that SRS27 has a wide therapeutic window as no toxicity symptoms were detected with a dose up to 60 mg/kg daily when tested for 14 days. These results provide strong justification for further investigation of SRS27 as a potential new anti-asthma agent.

Polymeric Nanoparticles-Based Brain Delivery with Improved Therapeutic Efficacy of Ginkgolide B in Parkinson's Disease.

PURPOSE: Ginkgolide B (GB) is a terpene lactone derivative of Ginkgo biloba that is believed to function in a neuroprotective manner ideal for treating Parkinson's disease (PD). Despite its promising therapeutic properties, GB has poor bioavailability following oral administration and cannot readily achieve sufficient exposure in treated patients, limiting its clinical application for the treatment of PD. In an effort to improve its efficacy, we utilized poly(ethylene glycol)-co-poly(ε-caprolactone) (PEG-PCL) nanoparticles as a means of encapsulating GB (GB-NPs). These NPs facilitated the sustained release of GB into the blood, thereby improving its ability to accumulate in the brain and to treat PD. METHODS AND RESULTS: Using Madin-Darby canine kidney (MDCK) cells, we were able to confirm that these NPs could be taken into cells via multiple nonspecific mechanisms including micropinocytosis, clathrin-dependent endocytosis, and lipid raft/caveolae-mediated endocytosis. Once internalized, these NPs tended to accumulate in the endoplasmic reticulum and lysosomes. In zebrafish, we determined that these NPs were readily able to undergo transport across the chorion, gastrointestinal, blood-brain, and blood-retinal barriers. In a 1-methyl-4-phenylpyridinium ion (MPP+)-induced neuronal damage model system, we confirmed the neuroprotective potential of these NPs. Following oral administration to rats, GB-NPs exhibited more desirable pharmacokinetics than did free GB, achieving higher GB concentrations in both the brain and the blood. Using a murine PD model, we demonstrated that these GB-NPs achieved superior therapeutic efficacy and reduced toxicity relative to free GB. CONCLUSION: In conclusion, these results indicate that NPs encapsulation of GB can significantly improve its oral bioavailability, cerebral accumulation, and bioactivity via mediating its sustained release in vivo.

Low Oral Bioavailability and Partial Gut Microbiotic and Phase II Metabolism of Brussels/Witloof Chicory Sesquiterpene Lactones in Healthy Humans.

Free and glycosylated sesquiterpene lactones (SLs), which are abundant in leafy vegetables including Brussels/witloof chicory, possess health-promoting effects in vivo. However, the pharmacokinetics of dietary source of SLs remain largely unknown. In this open-label and single-dose trial, sixteen healthy volunteers consumed 150 g of Brussels/witloof chicory juice containing 48.77 µmol SLs in 5 min. Blood, urine, and fecal samples were collected before and after chicory consumption in 24 h. No SLs were detected in the serum, urine, and fecal samples before chicory consumption in all of the participants. Chicory consumption increased lactucin, 11ß,13-dihydrolactucin, and their glucuronide/sulfate conjugates, rather than lactucopicrin and 11ß,13-dihydrolactucopicrin, as well as glycosylated SLs in biological samples. The peak concentration of total SLs in serum reached 284.46 nmol/L at 1 h, while, in urine, this peak was 220.3 nmol between 2 and 6 h. The recovery of total SLs in blood, urine, and feces was 7.03%, 1.13%, and 43.76% of the ingested dose, respectively. Human fecal suspensions with intestinal microbiota degraded glycosylated SLs in chicory, and converted lactucopicrin and 11ß,13-dihydrolactucopicrin to lactucin and 11ß,13-dihydrolactucin, respectively. Collectively, Brussels/witloof chicory SLs are poorly bioavailable and they undergo partial gut microbial and phase II metabolism in humans.

Investigation on the urinary excretion kinetics of three atractylenolides from crude and processed Atractylodis rhizoma extracts in rats by UPLC-MS/MS.

Atractylodis rhizoma is a frequently-used traditional Chinese medicine in clinical practice, which have the effect of eliminating dampness and tonifying spleen. And after being processed with wheat bran, the dryness of A. rhizoma is reduced, and the function of tonifying spleen is enhanced. Atractylenolides are the major bioactive components of A. rhizoma, including atractylenolide I (AI), atractylenolide Ⅱ (AⅡ) and atractylenolide Ⅲ (AⅢ). The present study aimed to develope a new UPLC-MS/MS method for simultaneous quantification of three atractylenolides in rat urine, and applied to the excretory kinetics in Sprague-Dawley rats after oral administration of crude and processed A. rhizoma extracts. Analytes and internal standard were detected without interference in the multiple reaction monitoring (MRM) mode with positive electrospray ionization. The excretory kinetics parameters were calculated by a urine drug analysis model of drug and statistics (DAS) 3.2.8 software. The t1/2 and Ke of three atractylenolides had no significant difference between crude and processed A. rhizoma, but the recovery accumulative excretion of them in processed A. rhizoma were apparently higher than the crude ones (p<0.05, p<0.01). The results showed that only a small amount of atractylenolides excreted in urine and processing A. rhizoma with wheat bran by stir frying could promote the urinary excretion of them.

Determination of Lekethromycin, a Novel Macrolide Lactone, in Rat Plasma by UPLC-MS/MS and Its Application to a Pharmacokinetic Study.

Lekethromycin, a new macrolide lactone, exhibits significant antibacterial activity. In this study, a reliable analytical ultrahigh-performance liquid chromatography electrospray ionization quadrupole Orbitrap high-resolution mass spectrometry (UPLC-ESI-Orbitrap-MS) method was established and validated for the detection of lekethromycin in rat plasma. After a simple acetonitrile (ACN)-mediated plasma protein precipitation, chromatographic separation was performed on a Phenomenex Luna Omega PS C18 column (30 × 2.1 mm i.d. particle size = 3 µm) conducted in a gradient elution procedure using 0.5% formic acid (FA) in ACN and 0.5% FA in water as the mobile phase pumped at a flow rate of 0.3 mL/min. Detection was carried out under positive electrospray ionization (ESI+) conditions in parallel reaction monitoring (PRM) mode with observation of m/z 804.5580 > 577.4056 for lekethromycin and 777.5471 > 619.4522 for gamithromycin (internal standard, IS). The linear range was 5-1000 ng/mL (r2 > 0.99), and the lower limit of quantification (LLOQ) was 5 ng/mL. The intra- and inter-day precision (expressed as relative standard deviation, RSD) values were ≤7.3% and ≤6.3%, respectively, and the accuracy was ≥90% ± 5.3%. The mean extraction recovery RSD valWeue was <5.1%. Matrix effects and dilution integrity RSD values were <5.6% and <3.2%, respectively. Lekethromycin was deemed stable under certain storage conditions. This fully validated method was effectively applied to study the pharmacokinetics of lekethromycin after a single intravenous administration of 5 mg/kg in rats. The main pharmacokinetic parameters were T1/2λz, CL_obs and VZ_obs were 32.33 ± 14.63 h, 0.58 ± 0.17 L/h/kg and 25.56 ± 7.93 L/kg, respectively.

Human Gut Microbiota Metabolism of Dietary Sesquiterpene Lactones: Untargeted Metabolomics Study of Lactucopicrin and Lactucin Conversion In Vitro and In Vivo.

SCOPE: Gut microbiota converts dietary phytochemicals into metabolites and modulates their health effects. The microbial metabolism of dietary terpenoids, as the sesquiterpene lactones of leafy vegetables, is unknown. METHODS AND RESULTS: In vitro fermentation of lactucopicrin, lactucin, and romaine lettuce with gut microbiota from independent donors, show their extensive metabolism through untargeted metabolomics of the fecal incubations. Dehydroxylations and double bond hydrogenations are the main catabolic reactions. Isomers of dihydrolactucopicrin, tetrahydrolactucopicrin, and deoxylactucin, are observed after lactucopicrin metabolism. Tetrahydrolactucin and hexahydrolactucin are also found after lactucin metabolism. Lettuce fermentation shows similar metabolic conversions. Phase II conjugates of most of these metabolites are detected in the urine of healthy volunteers after escarole salad intake. Glucuronides, and sulfates, of dihydrolactucopicrin, tetrahydrolactucopicrin, dihydrolactucin, and deoxylactucin, are detected in the urine although with large inter-subject variability. CONCLUSION: This is the first report on the gut microbiota metabolism of sesquiterpene lactones in humans, and one of the first reports to describe that dietary terpenoids of widely consumed leafy vegetables are extensively catabolized by human gut microbiota. A large inter-subject variation in the metabolism of sesquiterpene lactones also reflects differences in gut microbiota composition. It suggests that inter-individual differences in their health effects should be expected.

Use of toxicokinetic data for afidopyropen to determine the dose levels in developmental toxicity studies.

Afidopyropen is an insecticide that acts as a TRPV channel modulator in chordotonal organs of target insects and has been assessed for a wide range of toxicity endpoints including developmental toxicity in rats and rabbits. The GLP developmental toxicity study in rabbits did not produce evidence of maternal or fetal toxicity at the highest dose tested (32 mg/kg/day) but pharmacokinetics (PK) in pregnant rabbits in this study exhibited onset of PK nonlinearity from 5 mg/kg/day on, as measured by plasma Cmax and AUC. The NOAEL (32 mg/kg/day) is 9000X higher than maximum expected human dietary exposures to afidopyropen; the dose range where nonlinear PK were observed (5-15 mg/kg/day) is 1400-4200X higher. As nonlinearity occurred between 5 and 15 mg/kg/day, 32 mg/kg/day is concluded to be a sufficiently high dose (kinetically derived maximum dose) for a prenatal developmental toxicity study. As recognized by regulatory dose-selection guidance, onset of saturated PK is evidence of excessive biological stress to test animals rendering any effects at such doses of questionable relevance for human risk assessment. These data demonstrate that consideration of PK is critical for improving the dose-selection in developmental toxicity studies to enhance human relevance of animal toxicity studies.

Highly stabilized nanocrystals delivering Ginkgolide B in protecting against the Parkinson's disease.

As a major cause of neurodegeneration in the elderly, Parkinson's disease (PD) has attracted intense research attention. PD results from a decline in the numbers of dopaminergic neurons. Due to low levels of plasma exposure and the drug efflux properties of neuronal cells, orally delivering anti-PD drugs is challenging. Nanocrystals (NCs) can increase dissolution velocities and saturation solubility, improving oral bioavailability and brain uptake. In this study, Ginkgolide B (GB), a potent anti-Parkinsonism compound, was selected to verify the utility of NCs to effectively accumulate GB in both the blood and brain. Highly stabilized GB-NCs had small sizes, high rates of dissolution, enhanced cellular uptake and permeability. The GB-NCs could protect neurons against cytotoxicity induced by MPP+, and showed no toxicity in zebrafish. Fluorescent imaging in zebrafish indicated high levels of the NCs in both the gut and brain. When orally administrated to rats, the GB-NCs showed higher drug plasma levels and neuronal drug distributions when compared to control groups. Importantly, in MPTP-induced PD model, GB-NCs treatment resulted in improved behavior, reduced dopamine deficiency, and elevated dopamine metabolite levels. In summary, these highlight the fabrication of GB-NCs as effective drug carriers for the neuronal delivery of anti-PD therapies.

Screening and pharmacodynamic evaluation of the anti-respiratory syncytial virus activity of butene lactones in vitro and in vivo.

A series of butene lactones were synthesized and these compounds were tested for anti-respiratory syncytial virus (RSV) activity in vitro. Three compounds exhibited an antiviral effect, the highest of which was compound 6b3 with an effective concentration 50% of 6.35 µM. The effects of 6b3 were then evaluated in vivo and a significant reduction in the lung index caused by RSV was detected. Reduced inflammatory infiltration and necrosis of the lungs were revealed by histopathology and gross pathology. Activation of an early immune response by 6b3 was also observed by cytokine analysis via a real-time polymerase chain reaction. These results indicated that 6b3 has an anti-RSV effect both in vitro and in vivo, and is a possible candidate compound for the development of an anti-RSV drug in the future.

Bioavailability and Pharmacokinetics of Anisatin in Mouse Blood by Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry.

BACKGROUND: Anisatin is a neurotoxic sesquiterpene dilactone wildly found in plants of the family Illiciaceae. Due to morphological similarities among Illiciaceae fruits, fatal poisonings are frequent. OBJECTIVE: This study is aimed at developing a rapid, simple ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method to determine anisatin's bioavailability in mouse blood and the method's application to pharmacokinetics. METHODS: Blood samples were preprocessed by protein precipitation using acetonitrile. Salicin (internal standard, IS) and anisatin were gradient-eluted by a mobile phase of methanol and water (0.1% formic acid) in a UPLC BEH C18 column. This step involved using an electrospray ionization source of anisatin at a mass-to-charge ratio (m/z) of 327.1 → 127.0 and IS at m/z 285.1 → 122.9 in the negative ion mode with multiple reaction monitoring. RESULTS: The calibration curve ranged from 1 to 2000 ng/ml (r > 0.995), with the method's accuracy ranging from 86.3% to 106.9%. Intraday and interday precision were lower than 14%, and the matrix effect was between 93.9% and 103.3%. The recovery rate was higher than 67.2%. CONCLUSIONS: The developed UPLC-MS/MS method was successfully used for a pharmacokinetic study of oral (1 mg/kg) and intravenous (0.5 mg/kg) administration of anisatin to mice-the absolute bioavailability of anisatin in the mouse blood was 22.6%.

Prediction of the pharmacokinetics and pharmacodynamics of topiroxostat in humans by integrating the physiologically based pharmacokinetic model with the drug-target residence time model.

Topiroxostat is a selective xanthine oxidoreductase (XOR) inhibitor for the management of hyperuricemia in patients with or without gout. In this work, we aim to employ the physiologically based pharmacokinetic (PBPK) model with the drug-target residence time model to predict and characterize both the pharmacokinetics (PK) and pharmacodynamics (PD) of topiroxostat in humans. The plasma concentration-time profile of topiroxostat was simulated based on drug properties and human physiology parameters. The predictive power of this PBPK model was then demonstrated by comparison of stimulated to observed pharmacokinetic parameters. The utility of the model was further demonstrated through predicting the oral absorption and disposition characteristics of topiroxostat in humans. Finally, by combining the PBPK model and the drug-target residence time model, we successfully predicted the target occupancy and built the relationship between PK and PD using in vitro, in vivo and in silico information. The results showed that topiroxostat exhibited significant in vivo pharmacological activity even after the complete clearance of this drug from the liver (target site), which may be due to the long residence time of the binary topiroxostat-XOR complex. This work may be helpful to guide future investigations of topiroxostat and also provides a novel strategy for PK/PD studies.

Pharmacokinetics and pharmacodynamics analysis of XQ-1H and its combination therapy with clopidogrel on cerebral ischemic reperfusion injury in rats.

Ischemic stroke is the main cause of disability and mortality worldwide. 10-O-(N N-dimethylaminoethyl)-ginkgolide B methane-sulfonate (XQ-1 H) is a novel drug based on the remedial approach for ischemic stroke. Clopidogrel, a widely used anti-platelet drug, is often co-prescribed in the clinic. In this study, we established an UPLC-MS/MS spectrometry method for the determination of XQ-1H and investigated the pharmacokinetic effect of clopidogrel on XQ-1H in rats subjected to middle cerebral artery occlusion (MCAO). Meanwhile, the anti-apoptotic and neuroprotective effects of XQ-1H and its combination with clopidogrel were also studied. The results revealed that XQ-1H and its combination with clopidogrel abridged brain infarct volume, cerebral edema and alleviated neurological dysfunction caused by cerebral ischemic reperfusion injury. Further study demonstrated that XQ-1H combined with clopidogrel lessened TUNEL positive cells, up-regulated bcl-2 expression notably and down-regulated bax expression as compared to both XQ-1H and clopidogrel individually. In addition, a rapid, sensitive UPLC-MS/MS method was developed to quantify the concentration of XQ-1H in MCAO/R rats. Our pharmacokinetic results showed that clopidogrel significantly increased the exposure of XQ-1H, increased the peak plasma concentration (Cmax), area under the curve (AUC) and slowed elimination of XQ-1H in the co-administered group. Besides, for further exploring which CYP450 isoforms are involved in the XQ-1H metabolism, XQ-1H was incubated in human liver microsomes (HLMs) system with or without P450 isoform-selective inhibitors. Our results revealed that clopidogrel altered pharmacokinetics of XQ-1H potentially and subsequently enhanced the pharmacological effect of XQ-1H. Moreover, XQ-1H could be applied as an efficacious neuroprotective agent for ischemic stroke because of its considerable effect on averting neuronal apoptosis.