Pharmacokinetics of ginkgolide B-lyophilized nanoparticles after intravenous injection in rats using liquid chromatography-tandem mass spectrometry.

RATIONALE: Ginkgolide B (GB) performs diverse pharmacological activities but has poor water solubility. The currently available GB injections have a short half-life and are lethal when injected rapidly. We prepared GB-lyophilized nanoparticles (GB-NPs) using a new nonsurfactant polysaccharide polymer, ZY-010, as its carrier to regulate the release of GB in vivo. Here, the pharmacokinetics (PK) of GB-NPs after intravenous injection in rats was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). METHODS: The samples were separated on an Agilent Eclipse XDB-C 18 column (2.1 × 50 mm, 1.85 µm) maintained at 30°C. The MS/MS transitions of GB and glibenclamide as the internal standard (IS) were set at m/z 423.1 → 367.1 and m/z 492.1 → 367.0, respectively. The standard curve of GB content was constructed, and the specificity, sensitivity, precision, and extraction recovery of LC-MS/MS analysis were assessed. The main PK parameters were analyzed using DAS (Drug And Statistics for Windows) software, version 2.0. RESULTS: The retention time of GB and IS at elution was 2.77 and 4.75 min, respectively. An excellent linear response across the concentration range of 0.001-100 µg/ml was achieved (r = 0.9997). The relative standard deviation value of precision was less than 10%. The total extraction recovery was above 80.76 ± 2.08%. The main PK parameters for the GB-NPs were as follows: t1/2 = 69.32 h, AUC(0 → ∞) = 188 312.97 ± 143 312.41 µg/L h, CL = 0.03 ± 0.02 L/h/kg, and V = 0.09 ± 0.05 L/kg. The t1/2 of the GB-NPs was significantly longer than that of GB solution, and AUC(0 → ∞) of GB-NPs was about 1.4 times that of GB solution. The PK data demonstrated that the blood concentration of GB in rats conformed to a three-compartment model in both GB solution and GB-NPs. CONCLUSION: A rapid and accurate LC-MS/MS method was established for the determination of GB-NPs in rats. GB-NPs exhibited a sustained-release behavior in vivo compared with GB solution.

Enhanced anti-amnestic effect of donepezil by Ginkgo biloba extract (EGb 761) via further improvement in pro-cholinergic and antioxidative activities.

ETHNOPHARMACOLOGICAL RELEVANCE: EGb 761 is a standardized dry extract of Ginkgo biloba L. leaves traditionally used by Eastern Asia and has been associated with beneficial effects on neurodegeneration disorders, including Alzheimer's disease. AIM OF THE STUDY: Since beneficial interactions between EGb 761 and donepezil have been observed in previous clinical studies, the current study was proposed aiming to further explore related mechanisms from both pharmacokinetics and pharmacodynamics aspects. MATERIALS AND METHODS: Pharmacodynamic interactions were studied in scopolamine-induced cognitive impairment rats received two-weeks treatment of vehicle, EGb 761 and/or donepezil by the Morris water maze test and ex vivo evaluation of biomarkers of cholinergic transmission and oxidative stress in rat brain. In the meantime, pharmacokinetic profiles of donepezil and bilobalide were obtained and compared among all treatment groups. In addition, impact of the bioavailable EGb 761 components on donepezil brain penetration was evaluated with the hCMEC/D3 cell monolayer model. RESULTS: Scopolamine-induced rats with co-treatment of EGb 761 and donepezil had significantly improved cognitive function in the Morris water maze test with increased brain levels of superoxide dismutase and decreased brain levels of acetylcholinesterase and malondialdehyde than that with treatment of only EGb 761 or donepezil. Despite such beneficial pharmacodynamics outcomes, the two-week co-treatment of EGb 761 and donepezil did not alter the plasma pharmacokinetics and brain uptake of donepezil or bilobalide, which was further verified in the hCMEC/D3 monolayer model. CONCLUSION: Co-administration of EGb 761 and donepezil exerted better anti-amnestic effect via further enhanced pro-cholinergic and antioxidative effects of EGb 761 or donepezil in scopolamine-induced cognitive impairment rat without alteration in their systemic/brain exposure.

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.

Preparation of Ginkgolide Solid Dispersions with Low-Molecular-Weight Chitosan and Assessment of their Protective Effect on Isoproterenol- Induced Myocardial Injury.

BACKGROUND: Ginkgolides are widely used in cardio-protective therapy; however, poor bioavailability currently limits their application. OBJECTIVE: The purpose of this study was to demonstrate whether solid dispersions prepared with Low- Molecular-Weight Chitosan (LMWC) could improve the protective effect of ginkgolides on Myocardial Injury (MI). METHODS: Ginkgolide Solid Dispersions (GKSD) were prepared with LMWC. Their properties were then characterized using differential scanning calorimetry, X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. In vivo pharmacokinetic studies were performed in rats, and the protective effect of GKSD on MI was investigated by western blotting and immunohistochemical analyses. RESULTS: Drug dissolution testing showed that GDSD were released at a significantly higher rate than ginkgolides, dissolved by alternative methods, suggesting that LMWC facilitates the release of ginkgolides. Differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy all showed that GKSD was amorphous. In-vivo testing revealed larger AUC0-t, higher Cmax, and shorter Tmax for GKSD compared to that in original ginkgolides. Myocardial injury was induced in rats with isoproterenol to test the protective effect of GKSD. GKSD alleviated MI and reduced myocardial fibrosis, as observed by Hematoxylin and Eosin staining. Compared with the crude drug group, the secretion of malonyl dialdehyde and nitric oxide and expression of NOX-2 and NOX-4 were lower. The activities of the cardiac marker enzymes SOD, CAT, GPX, GPX-1, and GSH were higher in GKSD-administered rats, indicating a beneficial effect of GKSD in eliminating free radicals during myocardial injury. Additionally, western blotting and immunohistochemical analysis showed that GKSD markedly reduced the expression of signaling proteins RHOA, ROCK1, ROCK2, and RAC1. CONCLUSION: Solid dispersions prepared with low molecular weight chitosan improved the oral bioavailability of ginkgolide and enhanced its protective effect on myocardial injury.

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.

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.

Mixing Ginkgo biloba Extract with Sesame Extract and Turmeric Oil Increases Bioavailability of Ginkgolide A in Mice Brain.

Ginkgo biloba extract (GBE) is widely used as herbal medicine. Preventive effect of GBE against dementia, including Alzheimer's disease, has been reported. The bioactive compounds in GBE that impart these beneficial effects, flavonoids and terpene lactones, have poor bioavailability. Our previous study found distribution of bioactive compounds of sesame extract in mice brain after mixing it with turmeric oil. Here, we evaluate the distribution of bioactive compounds of GBE by combining it with the mixture of sesame extract and turmeric oil (MST). The content of terpene lactones in mice serum was significantly increased in a dose-dependent manner after administration of GBE. However, the contents of terpene lactones in mice brain were not significantly changed. Concentration of ginkgolide A in mice brain increased significantly when GBE was co-administrated with MST than when GBE was administered alone. These results suggest that MST may be effective in enhancing the bioavailability of ginkgolide A in GBE.

Influence of organic anion transporter 1/3 on the pharmacokinetics and renal excretion of ginkgolides and bilobalide.

ETHNOPHARMACOLOGICAL RELEVANCE: The major terpene lactones of ginkgo biloba extract (GBE) include ginkgolide A, B, C and bilobalide are used for the protection of cardiovascular, cerebrovascular and neurodegenerative diseases. Terpene lactones are orally bioavailable and predominantly eliminated via the renal pathway. However, information on the transporters involved in the pharmacokinetics (PK) and renal excretion of terpene lactones is limited. AIM OF THE STUDY: The objective of this study is to assess the role of OAT1/3 which are important transporters in the human kidney in the PK and renal excretion ginkgolide A, B, C and bilobalide. MATERIALS AND METHODS: Uptake of ginkgolide A, B, C and bilobalide in Madin-Darby Canine Kidney (MDCK) and human embryonic kidney 293 (HEK293) cells overexpressing OAT1 or OAT3, respectively were studied. To verify the result from in vitro cell models, the studies on PK, kidney accumulation and urinary excretion of ginkgolide A, B, C and bilobalide were carried out in rats. RESULTS: The result showed that ginkgolide A, B, C and bilobalide are low-affinity substrates of OAT1/3. Following co-administration with probenecid, a typical inhibitor of OAT1/3, the rat plasma concentrations of ginkgolide A, B, C and bilobalide increased significantly. AUC showed a significant increase in the probenecid-treated rats compared to control rats (893.48 vs. 1123.85, 314.91 vs. 505.74, and 2724.97 vs. 3096.40 µg/L*h for ginkgolide A, B and bilobalide, respectively), while the clearance of these compounds significantly decreased. The accumulation of ginkgolide A, B and bilobalide in the kidney of the probenecid-treated rats was reduced by 1.8, 2.4, and 1.5-fold, respectively; further reducing the cumulative urinary recovery of these compounds. CONCLUSION: The findings indicated that ginkgolide A, B and bilobalide are excreted via OAT1/3-mediated transport in the kidney and OAT1/3 inhibitor significantly influence the PK ginkgolides and bilobalide.

Human pharmacokinetics of ginkgo terpene lactones and impact of carboxylation in blood on their platelet-activating factor antagonistic activity.

Terpene lactones are a class of bioactive constituents of standardized preparations of Ginkgo biloba leaf extract, extensively used as add-on therapies in patients with ischemic cardiovascular and cerebrovascular diseases. This investigation evaluated human pharmacokinetics of ginkgo terpene lactones and impact of their carboxylation in blood. Human subjects received oral YinXing-TongZhi tablet or intravenous ShuXueNing, two standardized ginkgo preparations. Their plasma protein-binding and platelet-activating factor antagonistic activity were assessed in vitro. Their carboxylation was assessed in phosphate-buffered saline (pH 7.4) and in human plasma. After dosing YinXing-TongZhi tablet, ginkgolides A and B and bilobalide exhibited significantly higher systemic exposure levels than ginkgolides C and J; after dosing ShuXueNing, ginkgolides A, B, C, and J exhibited high exposure levels. The compounds' unbound fractions in plasma were 45-92%. Apparent oral bioavailability of ginkgolides A and B was mostly >100%, while that of ginkgolides C and J was 6-15%. Bilobalide's bioavailability was probably high but lower than that of ginkgolides A/B. Terminal half-lives of ginkgolides A, B, and C (4-7 h) after dosing ShuXueNing were shorter than their respective values (6-13 h) after dosing YinXing-TongZhi tablet. Half-life of bilobalide after dosing the tablet was around 5 h. Terpene lactones were roughly evenly distributed in various body fluids and tissues; glomerular-filtration-based renal excretion was the predominant elimination route for the ginkgolides and a major route for bilobalide. Terpene lactones circulated as trilactones and monocarboxylates. Carboxylation reduced platelet-activating factor antagonistic activity of ginkgolides A, B, and C. Ginkgolide J, bilobalide, and ginkgo flavonoids exhibited no such bioactivity. Collectively, differences in terpene lactones' exposure between the two preparations and influence of their carboxylation in blood should be considered in investigating the relative contributions of terpene lactones to ginkgo preparations' therapeutic effects. The results here will inform rational clinical use of ginkgo preparations.

The pharmacokinetics study of ginkgolide A, B and the effect of food on bioavailability after oral administration of ginkgolide extracts in beagle dogs.

Ginkgolides are the primarily active components in Ginkgo products that are popular worldwide. However, few studies have evaluated the bioavailability of ginkgolides and the effects of food on it after oral administration of ginkgolides. In this article, pharmacokinetics and absolute bioavailability of the primary components in ginkgolide extracts were evaluated in beagle dogs. For the first time, we showed that the fed dogs had significantly increased area under the concentration-time curve and peak concentration relative to the fasted dogs based on the data from both the prototype form and total lactones of ginkgolide A (GA) and ginkgolide B (GB). In terms of the free form of the prototype ginkgolides, the absolute bioavailabilities of GA and GB were 34.8 and 5.2% in the fasted dogs, respectively, which significantly increased to an average of 78.6 and 17.0%, respectively, in the fed dogs. In terms of acidified total lactones, the absolute bioavailabilities of GA and GB were 7.5 and 14.5% in the fed dogs, and the percentages declined to 4.1 and 3.7% in the fasted dogs, respectively. It was suggested that administration of ginkgolides after meals could promote the in vivo exposure and the bioavailability of GA and GB, and hence potentially enhance therapeutic outcomes.

Optimization of the Preparation Conditions of Borneol-Modified Ginkgolide Liposomes by Response Surface Methodology and Study of Their Blood Brain Barrier Permeability.

Ginkgolides (GG), containing ginkgolide A (GA), ginkgolide B (GB) and ginkgolide C (GC), are mainly prescribed for ischemic stroke and cerebral infarction. However, the ginkgolides can hardly pass the blood-brain barrier (BBB) into the brain. The purpose of this study was to prepare borneol-modified ginkgolides liposomes (GGB-LPs) to study whether borneol could enhance the transport of ginkgolides across the BBB. The preparation conditions of GGB-LPs were optimized by a response surface-central composite design. Also, pharmacokinetics and biodistribution studies of GGB-LPs were conducted using UPLC-MS. The optimal preparation conditions for GGB-LP were as follows: ratio of lipid to drug (w/w) was 9:1, ratio of phospholipid to cholesterol (w/w) was 7:1, and hydrate volume was 17.5 mL. Under these conditions, the GGB-LP yield was 89.73 ± 3.45%. With GGB-LPs, borneol significantly promoted the transport of ginkgolide across the BBB. The pharmacokinetic parameters of GGB-LP were significantly improved too, with Tmax of 15 min and a high drug concentration of 3.39 µg/g in brain. Additionally, the drug targeting index and relative uptake rate of GGB-LP was increased. Borneol-modified ginkgolide liposomes can thus potentially be used to improve the BBB permeability of gingkolide formulations.

A metabolic exposure-oriented network regulation strategy for the identification of effective combination in the extract of Ginkgo biloba L.

Nowadays, network pharmacology-based methods were increasing proposed to screen synergistic or combinatorial compounds from herbal medicines (HMs), while these researches mainly focused on structural prediction or experiment-based interaction between single compound and target protein. The proportion of each chemical in the nature and their metabolic process was ignored, which might decide an optimized composition for their synergistic effect. To exact the effective combination of HMs, a metabolic distribution-oriented network regulation strategy was developed for the identification of effective combination. Firstly, comprehensive chemical profiling and metabolic exposure of HMs in a pathological state were conducted. Then the effective combination for HMs was screened by combining network regulation and the metabolic exposure level of HMs. Finally, with the extract of Ginkgo biloba (EGB) as a case, a combination of 12 active compounds was found for treating ischemia stroke, showing bioactivity equivalence with original herb. The results also indicated that beside the well-known ginkgolides and flavonoids, trace compounds might also play an important role of the holistic effect of EGB. This method can be used as an alternative for effective combination screening.

Pharmacokinetics of the prototype and hydrolyzed carboxylic forms of ginkgolides A, B, and K administered as a ginkgo diterpene lactones meglumine injection in beagle dogs.

Ginkgo diterpene lactones meglumine injection (GDLI) is a commercially available product used for neuroprotection. However, the pharmacokinetic properties of the prototypes and hydrolyzed carboxylic forms of the primary components in GDLI, i.e., ginkgolide A (GA), ginkgolide B (GB), and ginkgolide K (GK), have never been fully evaluated in beagle dogs. In this work, a simple, sensitive, and reliable method based on ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) was developed, and the prototypes and total amounts of GA, GB, and GK were determined in beagle dog plasma. The plasma concentrations of the hydrolyzed carboxylic forms were calculated by subtracting the prototype concentrations from the total lactone concentrations. For the first time, the pharmacokinetics of GA, GB, and GK were fully assessed in three forms, i.e., the prototypes, the hydrolyzed carboxylic forms, and the total amounts, after intravenous administration of GDLI in beagle dogs. It was shown that ginkgolides primarily existed in the hydrolyzed form in plasma, and the ratio of hydrolysates to prototype forms of GA and GB decreased gradually to a homeostatic ratio. All of the three forms of the three ginkgolides showed linear exposure of AUC to the dosages. GA, GB, and GK showed a constant half-life approximately 2.7, 3.4, and 1.2 h, respectively, which were consistent for the forms at three dose levels (0.3, 1.0, and 3.0 mg·kg-1) and after a consecutive injection of GDLI for 7 days (1.0 mg·kg-1).

Design of amphiphilic PCL-PEG-PCL block copolymers as vehicles of Ginkgolide B and their brain-targeting studies.

The amphiphilic PEG-b-PCL block copolymers were synthesized by ring-opening polymerization. The specific and selective antagonists of platelet activating factor, Ginkgolide B (GB), was successfully encapsulated in the synthesized PEG-PCL nanoparticles (NPs) with high Encapsulation Efficiency and Drug Loading. The synthesis of different PEG-PCL copolymers were confirmed with FTIR and 1H NMR spectra. The morphology and particles size distribution of cargo-free PEG-PCL NPs were studied by transmission electron microscope (TEM) analysis and Malvern laser particle analyzer. The bio-distribution and pharmacodynamics studies of GB were studied with Wistar mice as the animal models via tail injecting of GB-PEG-PCL NPs. Results from Malvern laser particle analyzer and TEM analysis illustrated that the cargo-free NPs showed narrow distribution and well separated particles size of about 60 nm in diameter. The in vitro experiment of GB-PEG-PCL NPs exhibited an extended release behavior. The bio-distribution data suggested that Tween-80 covered GB-PEG-PCL NPs showed a brain-targeting behavior. The pharmacodynamics results confirmed that the GB-PEG-PCL NPs had an obvious cerebral protection effect.

Pharmacokinetics of ginkgolides A, B and K after single and multiple intravenous infusions and their interactions with midazolam in healthy Chinese male subjects.

PURPOSE: Ginkgo terpene lactones meglumine injection (GMI) is a novel preparation of traditional Chinese medicine that contains ginkgolides A, B and K (GA, GB, GK, respectively) as its primary components. In this study we evaluated the safety, tolerability and pharmacokinetics of these three ginkgolides after single and multiple intravenous infusions of GMI. We also investigated the effect of GMI on cytochrome P450 3A4 (CYP3A4) in healthy Chinese volunteers. METHODS: In this open-label, placebo-controlled study 15 subjects were randomly assigned to receive GMI or matched placebo (4:1 ratio). All subjects first received midazolam (MDZ) on day 1, followed by a 6-day washout. On Day 8, the subjects were started on once-daily dosing of either GMI or placebo for 14 days. Lastly, on Day 22 the subjects were given second dose of MDZ + GMI or MDZ + placebo. Plasma concentrations of ginkgolides, MDZ and its metabolite 1-hydroxy midazolam were quantified. RESULTS: The steady-state conditions of GA, GB and GK were achieved after 6 days of daily dosing. Following a single dose of GMI (Day 8) the area under the concentration-timecurve from zero to 24 h after administration (AUC0-24h) of GA, GB and GK (arithmetic ± standard deviation) was 4.10 ± 1.06, 4.61 ± 1.31 and 0.127 ± 0.102 h µg/mL, respectively; the corresponding values following multiple doses of GMI (Day 19) were 3.94 ± 1.16, 5.00 ± 1.55 and 0.118 ± 0.096 h µg/mL, respectively. The mean accumulation ratios were 0.95, 1.08 and 0.89 for GA, GB and GK, respectively. Additionally, the geometric mean [peak concentration (Cmax) and AUC0-24h] ratios of MDZ and 1-hydroxy midazolam were all within the specified acceptance ranges in the MDZ + placebo treatment and MDZ + GMI treatment. CONCLUSIONS: Our results show that GMI was well tolerated during the entire study. There was no systemic accumulation and no significant effects on the pharmacokinetics of MDZ in healthy Chinese male subjects after repeated dosing of GMI.

[Simultaneous determination of seven bioactive compounds and pharmacokinetics in rat plasma after oral administration of Yindan Xinnaotong Ruanjiaonang by UPLC-MS/MS].

To estabish ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for simultaneous determination of quercetin(QCT), isorhamnetin(ISR), kaempferol(KMF), ginkgolide A(GA), ginkgolide B(GB), ginkgolide C(GC) and bilobalide(BB) in rat plasma and investigate the pharmacokinetic process of seven compounds after oral administration of Yindan Xinnaotong Ruanjiaonang, The results indicated that all calibrations curves showed good linearity (r≥0.997 1). RSD of intra-day and inter-day precisions were all within 11%. The matrix effects and extraction recovery were in the range of 93.28%-103.6% and 72.43%-95.77% respectively. The peak concentration (Cmax) of QCT, ISR, KMF, GA, GB, GC and BB were (45.02±11.28), (49.90±13.82), (27.85±8.38), (76.31±18.19), (76.54±15.43), (35.35±10.28), (48.70±12.34) µg•L⁻¹, respectively. The peak time (tmax) of seven constituents were (0.33±0.11), (0.50±0.23), (0.33±0.14), (0.75±0.29), (1.0±0.35), (1.5±0.23), (0.75±0.50) h, respectively. UPLC-MS/MS method established in this research was proved to be so rapid and sensitive that it can be applied to the pharmacokinetic study of seven bioactive constituents in Yindan Xinnaotong Ruanjiaonang.

Blood-brain barrier permeability of ginkgolide: Comparison of the behavior of PET probes 7α-[18F]fluoro- and 10-O-p-[11C]methylbenzyl ginkgolide B in monkey and rat brains.

The blood-brain barrier permeability of ginkgolide B was examined using positron emission tomography (PET) probes of a 18F-incorporated ginkgolide B ([18F]-2) and a 11C-incorporated methylbenzyl-substituted ginkgolide B ([11C]-3). PET studies in monkeys showed low uptake of [18F]-2 into the brain, but small amounts of [11C]-3 were accumulated in the parenchyma. Furthermore, when cyclosporine A was preadministered to rats, the accumulation of [18F]-2 in the rat brain did not significantly change, however, the accumulation of [11C]-3 was five times higher than that in the control rat. These results provide effective approaches for investigating the drug potential of ginkgolides.

Determination of Ginkgolides A, B, C, J and Bilobalide in Plasma by LC-ESI (-)/MS/MS (QQQ) and its Application to the Pharmacokinetic Study of Ginkgo Biloba Extract in Rats.

A simple, rapid, and specific high-performance liquid chromatograph coupled with a tandem mass spectrometry method has been developed and validated for the quantification of ginkgolides in rat plasma, and the main pharmacokinetic parameters of ginkgolides after oral administration of Ginkgo biloba extract (GBE) was acquired. Methods: Plasma samples were pretreated with ethyl acetate extraction. Sulfamethoxazole was used as the internal standard (IS). Chromatographic separation was achieved on an Eclipse XDB-C18 column (2.1 mm×150 mm, 5 µm) with a mobile phase consisting of methanol/0.1% formic acid water (gradient elution: 0~25 min (77:23)→(60:40), V/V) at a flow rate of 0.3 mL·min-1. The detection was performed on a triple quadruple tandem mass spectrometer using an electrospray ionization (ESI) source for 25 min. The detection was operated by multiple reaction monitoring(MRM) under negative ionization mode of the transitions of m/z 325→163 for BB, 469→423 for GJ, 439→125 for GC, 453→351 for GA, 423→367 for GB and of m/z 252→156 for sulfamethoxazole (IS) respectively. Results: The pharmacokinetic properties of BB, GJ, GA, GB and GC were in line with the open 2-compartment model after oral administration of GBE in rats; The pharmacokinetic parameters of various lactones were calculated, and drugs-time curve and the curve fitting diagram of 5 ginkgolides were drew; The absorption and distribution rate of BB, GJ, GA, GB and GC were fast in rats in vivo, and half-life of absorption was less than 3 h. Conclusion: The developed LC-ESI (-)/MS/MS (QQQ) method was successfully applied to assess the pharmacokinetic parameters and oral bioavailability of ginkgolides in rats after administration of GBE, which can provide basis for further clinical efficacy studies.

Pharmacokinetics and tissue distribution of ginkgolide A, ginkgolide B, and ginkgolide K after intravenous infusion of ginkgo diterpene lactones in a rat model.

Ginkgo diterpene lactones are compounds that are extracted from the Ginkgo biloba leaf and possess pharmacologic activities with neuroprotective effects. To address the poor bioavailability of ginkgo diterpene lactones, ginkgo diterpene lactone meglumine injection (GDLI) was formulated and is commercially available. In this study, a simple, sensitive and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for assessing the total amount and the amount of the prototype forms of ginkgolides A (GA), B (GB) and K (GK) in rat plasma and tissues. This method was used to calculate the concentrations of the hydrolysed carboxylic forms and assess the pharmacokinetics of the ginkgolides after intravenous (i.v.) GDLI administration in rats. Generally, all three ginkgolide forms showed dose-dependent plasma concentrations, and no obvious differences in pharmacokinetic parameters, i.e., area under the curve (AUC) of plasma concentration versus time and half-life, were observed after GDLI administration on 7 consecutive days. These ginkgolides primarily existed in the carboxylic form in the plasma, and the systemic concentrations of the carboxylic forms of GA and GB were 11- to 17- and 3- to 4-fold higher than those of their prototype forms, respectively. In contrast, dramatically increased levels of the GA and GB prototype lactones were detected in the liver and heart. GA, GB, and GK were extensively distributed in various organs/tissues; the highest levels were found in the kidneys, liver, and intestine, and the lowest levels were found in the brain. These data suggest that ginkgolides have difficulty crossing the blood-brain barrier and that their targets for protecting against cerebral ischaemia are located outside the central system.

[Absolute bioavailability of ginkgolide compounds in rats].

To investigate the pharmacokinetic characteristics and absolute bioavailability of ginkgolide A (GA), ginkgolide B (GB) and bilobalide (BB) in rats. In this experiment, a high-performance liquid chromatography-tandem mass spectrometry (LC-MS/ MS) method was established to determine the plasma concentrations of GA, GB and BB in rats after rats were administrated with the three drugs through ig and iv respectively. The main pharmacokinetic parameters and absolute bioavailability of three ginkgolide compounds were obtained by using pharmacokinetic software DAS 2. 0. After the inject of GA, GB and BB, the results showed Cmax at (513.9 ± 116.9), (701.3 ± 76.0), (5,255.6 ± 476.8) µg · L(-1) and AUC0.24h of (960.9 ± 268.5), (779.5 ± 140.6), (7,409.3 ± 1,181.1) µg · h · L(-1), respectively; after the oral administration, the results showed Cmax at (522.9 ± 39.9), (146.8 ± 31.6), (2,711.9 ± 588.9) µg · L(-1) and AUC0-24 h of (1,760.4 ± 300.7), (636.6 ± 180.3), (16,651.4 ± 1,306.5) µg · h · L(-1), respectively. The absolute bioavailability of GA, GB and BB in rats was (61.1 ± 10.4)%, (27.2 ± 7.7)%, (56.2 ± 4.4)%, respectively. The method established in this experiment has a good specificity and sensitivity and so can be used to study the pharmacokinetics and absolute bioavailability of GA, GB and BB in rats.