Jin-Gui-Shen-Qi Wan alleviates fibrosis in mouse diabetic nephropathy via MHC class II

ETHNOPHARMACOLOGICAL RELEVANCE

Jin-Gui-Shen-Qi Wan (JGSQW) is a traditional Chinese medicine formula that has been traditionally used to alleviate urinary system ailments such as frequent urination and polyuria. Clinical studies have indicated that when combined with hypoglycaemic drugs, JGSQW exhibits a synergistic effect and can improve diabetic nephropathy (DN), yet its underlying mechanism and targets remain unclear.

AIM OF THE STUDY

This study aims to investigate the therapeutic efficacy of JGSQW and its underlying mechanisms using a DN db/db mouse model.

MATERIALS AND METHODS

Ultrahigh-performance liquid chromatography coupled with mass spectrometry was utilized to analyse the primary active compounds, blood levels, and pharmacokinetics of JGSQW. Additionally, the therapeutic effects of JGSQW and metformin on blood glucose levels, lipid levels, renal function, and renal pathology in diabetic nephropathy mice were investigated using a db/db mouse model. Proteomic analysis was carried out to identify the primary target of JGSQW in treating DN. The mechanism of action was verified by western blotting, immunohistochemistry, and immunofluorescence. Then, molecular docking and molecular dynamics, transfection, drug affinity responsive target stability (DARTS) assay and cell thermal migration assay (CETSA) further validated the targeted binding effect.

RESULTS

JGSQW combined with metformin significantly improved the blood glucose levels, blood lipids, renal function, and renal pathology of DN mice. JGSQW mainly exerted its therapeutic effect on DN by targeting major histocompatibility complex class II (MHC class II) molecules. Immunohistochemistry results showed that JGSQW inhibited the expression of collagen I, fibronectin, and alpha smooth muscle actin (α-SMA) expression. Immunofluorescence and Western blot results showed that JGSQW inhibited the expression of H2-Ab1 and H2-Aa, which are MHC class II molecules, thereby suppressing CD4+ T-cell infiltration and improving diabetic kidney fibrosis. The binding ability of paeoniflorin to H2-Aa was predicted and verified by molecular, DARTS, and CETSA assays. Treatment with 80 μM paeoniflorin effectively alleviated high glucose-induced injury in the MPC-5 injury model. H2-Aa was overexpressed at this model concentration, and Western blotting further confirmed that paeoniflorin reduced glomerular podocyte fibrosis by regulating H2-Aa.

CONCLUSIONS

JGSQW combined with metformin may have a synergistic effect to alleviates renal fibrosis in diabetic nephropathy by downregulating immune complex MHC class II molecules and attenuating the antigen presentation effect of MHC class II on CD4.

Multi-Effect Enhanced Raman Scattering Based on Au/ZnO Nanorods Structures

Surface-enhanced Raman scattering (SERS) was considered a potential spectroscopic technique for applications of molecular detection and has drawn great research interest during the past decade. So far, fabrications of cost-effective SERS substrates with high sensitivity and stability and the corresponding enhanced mechanisms are always among the list of research topics, although great progress has been made. In this work, Au particles were decorated on Si, ZnO film and ZnO nanorod arrays simultaneously by an economical method of ion sputtering, generating three kinds of SERS substrates for R6G detection. The morphology difference of Au particles on different samples and the consequent influence on Raman scattering were studied. The experiment results exhibited that substrates with Au particles decorated on ZnO nanorods had the highest Raman enhancement factor. Furthermore, multi-effect enhanced mechanisms summarized as localized surface plasmon resonance (LSPR) filed coupling, electron transferring induced by LSPR of Au particles and whispering gallery mode (WGM) effect of the ZnO cavity were presented. This work provides a convenient and efficient method of fabricating SERS substrates and indicates that such proper metal/semiconductor composite structures are promising candidates for SERS applications.

Evaluation of Regional Economic Innovation Ability Based on Neural Network

In order to further improve regional economic innovation capability and governance level and solve the problems of lack of attention to evaluation indicators in traditional evaluation methods of regional economic innovation capability and easy to be affected by subjective factors, an evaluation model based on neural network algorithm is proposed. Through re-analysis of regional economic innovation capability evaluation indexes, the model defines the most reasonable combination of characteristics by combining information gain characteristic selection strategy and finally builds a scientific evaluation index system. By testing the prediction accuracy of the experimental discovery model and evaluation index, the neural network model improves by 41% compared with the traditional subjective evaluation method, and the accuracy increases by 20% compared with the GA-BP neural network model. The experiment proves the stability and good convergence effect of the evaluation model.

Effects of mesoscale eddies on intraseasonal variability of intermediate water east of Taiwan

The intraseasonal variability of the intermediate water (IW) and its characteristics east of Taiwan are studied utilizing 17 months of long-term, continuous and synchronous measurements of temperature, salinity and current from mooring sites deployed at 122° E/23° N from January 2016 to May 2017. Direct measurements revealed water masses east of Taiwan alternately show complete South China Sea Intermediate Water or North Pacific Intermediate Water (NPIW) characteristics, mostly in a mixed state, with NPIW dominating 70% of the time. For the first time, it is demonstrated that the variation of IW with periods of ~ 80 days is mainly related to mesoscale eddies. Anticyclonic (cyclonic) eddies corresponding to an increase (decrease) in temperature and salinity in the intermediate layer. Further mechanism analysis indicates the vertical motion of the water mass inside the eddies is one of the reasons for the thermohaline change in the intermedaiter layer. In addition, the anticyclonic eddies may increase the salinity concentration gradient across the Luzon Strait, and the enhanced advection is favorable to the outflow of water masses in the South China Sea. When the cyclonic eddies acts on the eastern part of Taiwan, the influence of the northward advection is weakened and the southward flow on its left side is more favorable to the transport of NPIW.

Flexible composite film with artificial opal photonic crystals for efficient all-day passive radiative cooling

All-day passive radiative cooling has recently attracted broader attention for its potential as a viable energy technology. Although tremendous progress has been achieved, the design and fabrication of low-cost high-efficiency radiators for all-day passive radiative cooling remains a challenge. Herein, we report a new type of flexible composite radiator film with built-in artificial opal-like structures for all-day passive radiative cooling. Using artificial opal structure concepts, the proposed polydimethylsiloxane (PDMS) radiator film with embedded polystyrene (PS) microsphere photonic crystals exhibits a sufficiently high solar reflectance of ∼92.7% when in a direct sunlight region, and a thermal emittance of ∼93.6% within the atmospheric window. Without the need for traditional reflectors like silver or aluminum foils, this composite film realizes subambient temperature reduction of ∼4.8 °C in direct sunlight and ∼8.5 °C during the night. This work provides a new fabrication approach for the low-cost production of structural polymer films for high performance and potential real word applications.

Observed three dimensional distributions of enhanced turbulence near the Luzon Strait

Ocean turbulence can impact the transfer of heat, nutrients, momentum and sea level rise, which are crucially important to climate systems. The Luzon Strait, one of the mixing hotspots, is important for water exchange between the northeastern South China Sea and West Pacific. Here, for the first time, we carry out full-depth direct microstructure measurements surrounding the Luzon Strait to clarify the three-dimensional distributions of turbulence. We demonstrate that the turbulent kinetic energy dissipation rates in the upper and middle layers of the northeastern South China Sea are on the same order of magnitude as those in the West Pacific. The dissipation rates are only bottom enhanced near the rough topography of the South China Sea slope and Luzon Strait which is one order of magnitude larger than those at smooth area. The relevant bottom diapycnal diffusivity in the South China Sea is elevated in the West Pacific by a factor of three, instead of by two orders of magnitude as overestimated by indirect parameterization. These results may appear surprising in light of previous studies but are in fact consistent with predictions from internal wave-topography interaction theory.

Bioequivalence of 2 Aripiprazole Orally Disintegrating Tablets in Healthy Chinese Volunteers Under Fasting and Fed Conditions

To assess the bioequivalence of 2 formulations of aripiprazole orally disintegrating tablets and to monitor their safety and tolerability in Chinese subjects, a single-site, open-label, randomized, 2-preparation, single-dose, 2-period crossover design was conducted. All 60 subjects were randomly divided into the fasting group and the fed group. Blood samples were collected at scheduled times after a single oral dose of orodispersible tablets containing 10 mg of aripiprazole. In the fasting state, the geometric mean ratios (90% confidence intervals [CIs]) of the test/reference formulation were 92.22%-100.20% for the area under the concentration-time curve (AUC) from time zero to the last measured concentration (AUC_0-t ), 91.73%-100.14% for the AUC from administration to infinite time (AUC_0-∞ ), and 98.52%-112.52% for the maximum plasma concentration (C_max ). In the fed state, AUC_0-t , AUC_0-∞ , and C_max were 92.23%-100.20%, 91.73%-100.14%, and 95.91%-105.13%, respectively. The 90%CIs of the test/reference AUC ratio and C_max ratio were within the acceptance range of 80.00%-125.00% for bioequivalence. Neither the maximum peak plasma concentration (t_max ) nor the terminal elimination half-life (t_1/2 ) showed any significant difference. No serious adverse events) were encountered during the study. The test and reference formulations were bioequivalent under both fasting and fed conditions and were found to be safe and tolerated.

Machine learning combining CT findings and clinical parameters improves prediction of length of stay and ICU admission in torso trauma

OBJECTIVE

To develop machine learning (ML) models capable of predicting ICU admission and extended length of stay (LOS) after torso (chest, abdomen, or pelvis) trauma, by using clinical and/or imaging data.

MATERIALS AND METHODS

This was a retrospective study of 840 adult patients admitted to a level 1 trauma center after injury to the torso over the course of 1 year. Clinical parameters included age, sex, vital signs, clinical scores, and laboratory values. Imaging data consisted of any injury present on CT. The two outcomes of interest were ICU admission and extended LOS, defined as more than the median LOS in the dataset. We developed and tested artificial neural network (ANN) and support vector machine (SVM) models, and predictive performance was evaluated by area under the receiver operating characteristic (ROC) curve (AUC).

RESULTS

The AUCs of SVM and ANN models to predict ICU admission were up to 0.87 ± 0.03 and 0.78 ± 0.02, respectively. The AUCs of SVM and ANN models to predict extended LOS were up to 0.80 ± 0.04 and 0.81 ± 0.05, respectively. Predictions based on imaging alone or imaging with clinical parameters were consistently more accurate than those based solely on clinical parameters.

CONCLUSIONS

The best performing models incorporated imaging findings and outperformed those with clinical findings alone. ML models have the potential to help predict outcomes in trauma by integrating clinical and imaging findings, although further research may be needed to optimize their performance.

KEY POINTS

• Artificial neural network and support vector machine-based models were used to predict the intensive care unit admission and extended length of stay after trauma to the torso. • Our input data consisted of clinical parameters and CT imaging findings derived from radiology reports, and we found that combining the two significantly enhanced the prediction of both outcomes with either model. • The highest accuracy (83%) and highest area under the receiver operating characteristic curve (0.87) were obtained for artificial neural networks and support vector machines, respectively, by combining clinical and imaging features in the prediction of intensive care unit admission.

Effect of soil pH on the transport, fractionation, and oxidation of chromium(III)

This work was conducted to study the effect of soil pH (4.0, 6.0, and 8.0) on the transport, fractionation, and oxidation of trivalent chromium [Cr(III)]. Variation in pH altered soil chemical and mineralogical properties such as zeta potential, cation exchange capacity and redox potential of natural soil. Breakthrough curves and batch sorption experiments coupled with fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses demonstrated that the easy mobility of Cr(III) in pH 4.0 soil was dominated by the limited coordination effect. The high retention of Cr(III) in pH 8.0 soil was mainly ascribed to the hydrolysis. Incubation experiments indicated that the proportions of Cr in exchangeable fraction decreased with increasing of soil pH and incubation time, and kinetics analysis revealed that the time dependent transformation was controlled by mass transfer and chemical processes (e.g., hydrolysis, ion association). The XPS confirmed the oxidation of Cr(III) in pH 8.0 soil during the incubation period. Furthermore, the content of toxic hexavalent chromium [Cr(VI)] was positively associated with time and initial concentration of Cr(III) released. These results revealed the hazardousness of Cr(III) in soil contaminated simultaneously by inorganic acid and alkali.

Intraseasonal oscillation of deep currents influenced by mesoscale eddies in the Kuroshio Extension Region

Intraseasonal oscillation of deep currents in the Kuroshio Extension region is examined using observations from a collection of current meter moorings. The moored observations reveal variability with characteristic time scales of 23–38 days for velocity time series and of 38–99 days for temperature time series. The time series of normalized temperature (NT) in the deep ocean change correspondingly with sea level anomaly (SLA). The maximum correlation coefficient between NT in the deep ocean and SLA is also up to 0.7. Positive correlation is observed between deep currents and surface geostrophic current. Furthermore, the influence of mesoscale eddies on deep currents is examined by analyzing the data collected when cyclonic and anticyclonic eddies crossed the current meter mooring. Whether anticyclonic or cyclonic eddy intensified the deep currents from 2000 m to 4000 m in the same direction and increased the amplitude. These results provide observational evidence of intraseasonal oscillation in the deep ocean and the effect of mesoscale eddies on deep currents in the Kuroshio Extension region.

[Pharmacokinetics Study of Phentolamine Mesylate Injection in Healthy Volunteers]

OBJECTIVE

To study the pharmacokinetic profile of phentolamine mesylate injection in healthy Chinese volunteers.

METHODS

A total of 16 healthy volunteers were randomly divided into two groups, each receiving anterior teeth submucosal infiltration anesthesia and inferior alveolar nerve block anesthesia, respectively. The participants were injected with 0.9 mL, 1.8 mL, and 3.6 mL of 2% lidocaine HCl with 1∶100 000 epinephrine over three periods sequentially, followed by corresponding sequential injection of 0.2 mg, 0.4 mg, 0.8 mg of phentolamine mesylate at the same sites 30 min later.Blood samples were drawn from 5 min before injection to 15 h post the injection of phentolamine mesylate (16 time points). Adverse events were closely observed all the time. Plasma phentolamine mesylate was detected using UPLC-MS/MS with isotope as internal standard. WinNolin 6.1 software was used to calculate the pharmacokinetic parameters.

RESULTS

Time to peak concerntration (T_max) ranged from 12 to 13 min. Half-time of elimination (t_1/2) ranged from 3.84 to 4.07 h, with a clearance (CL) of 190 L/h. Peak concentration (C_max), area under concentration-time curves from 0 to t hour and from 0 to infinite time (AUC_0-t and AUC_0-∞) increased proportionally in the dose range of 0.2 mg to 0.8 mg. The results of confidence interval analysis showed nearly linear dynamic characteristics for the injection of phentolamine mesylate. All participants experienced mild adverse events, including pain at the injection point, dizziness, and palpitations. These adverse events disappeared without treatments.

CONCLUSIONS

Phentolamine mesylate injection is effective for reversing oral local anesthetic effects.

Single balloon versus double balloon bipedicular kyphoplasty: a systematic review and meta-analysis

INTRODUCTION

Kyphoplasty has been widely used to treat vertebral compression fractures (VCFs). In standard procedure of kyphoplasty, two balloons were inserted into the vertebral body through bipedicular and inflated simultaneously, while using a single balloon two times is also a common method in clinic to lessen the financial burden of patients. However, the effect and safety of single balloon versus double balloon bipedicular kyphoplasty are still controversy.

METHODS

In this systematic review and meta-analysis, eligible studies were identified through a comprehensive literature search of PubMed, Cochrane library EMBASE, Web of Science, Wanfang, CNKI, VIP and CBM until January 1, 2018. Results from individual studies were pooled using a random or fixed effects model.

RESULTS

Seven articles were included in the systematic review and five studies were consisted in meta-analysis. We observed no significant difference between single balloon and double balloon bipedicular kyphoplasty in visual analog scale (VAS), angle (kyphotic angle and Cobb angle), consumption (operation time, cement volume and volume of bleeding), vertebral height (anterior height, medium height and posterior height) and complications (cement leakage and new VCFs), while the cost of single balloon bipedicular kyphoplasty is lower than that of double balloon bipedicular kyphoplasty. The results of our meta-analysis also demonstrated that single balloon can significantly improve the VAS, angle and vertebral height of patients suffering from VCFs.

CONCLUSION

This systematic review and meta-analysis collectively concludes that single balloon bipedicular kyphoplasty is as effective as double balloon bipedicular kyphoplasty in improving clinical symptoms, deformity and complications of VCFs but not so expensive. These slides can be retrieved under Electronic Supplementary Material.

Protein docking refinement by convex underestimation in the low-dimensional subspace of encounter complexes

We propose a novel stochastic global optimization algorithm with applications to the refinement stage of protein docking prediction methods. Our approach can process conformations sampled from multiple clusters, each roughly corresponding to a different binding energy funnel. These clusters are obtained using a density-based clustering method. In each cluster, we identify a smooth “permissive” subspace which avoids high-energy barriers and then underestimate the binding energy function using general convex polynomials in this subspace. We use the underestimator to bias sampling towards its global minimum. Sampling and subspace underestimation are repeated several times and the conformations sampled at the last iteration form a refined ensemble. We report computational results on a comprehensive benchmark of 224 protein complexes, establishing that our refined ensemble significantly improves the quality of the conformations of the original set given to the algorithm. We also devise a method to enhance the ensemble from which near-native models are selected.

[Determination of 5-hydroxytryptamine,Adrenalin and Noradrenalin in Human Plasma by Pre-column Derivatization HPLC-MS/MS]

OBJECTIVE

To establish a method for the determination of 5-hydroxy tryptamine (5-HT),adrenalin (AD) and noradrenalin (NA) in human plasma using pre-column derivatization HPLC-MS/MS. Methods Derivatives of the plasma samples were produced with dansyl chloride under pH 10.5,and then extracted and enriched with ethyl acetate. The detected chemicals were separated using Ultimate C₁₈ (50 mm×4.6 mm,5 μm) with acetonitrile-water-formic acid=95∶5∶0.05 (V∶V∶V) at 0.2 mL/min. The HPLC-MS//MS system was operated under a multiple reaction monitoring mode (MRM) using the electrospray ionization technique in positive mode.

RESULTS

Linear range of the calibration curve appeared in 250-2.5 ng/mL. The method had a less than 9% intra- and inter-assay relative standard deviation (RSD),95.44%-109.71% recoveries,and 4.86%-12.81% matrix effects.

CONCLUSION

This method is simple,accurate,and suitable for detection of 5-HT,AD and NA in human plasma.

Tribological properties of attapulgite/La2O3 nanocomposite as lubricant additive for a steel/steel contact

Attapulgite is a layered silicate with good friction-reduction and self-repairing properties. In order to further improve its tribological properties, the present work mainly focuses on the preparation of attapulgite/La₂O₃ nanocomposite and study on its tribological behaviors. The tribological properties of mineral lubricating oil (150SN) containing attapulgite/La₂O₃ nanocomposite were investigated through an Optimal SRV-IV oscillating friction and wear tester. The rubbing surfaces and generated tribofilms were characterized by SEM, EDS, XPS and nanoindentation. Results indicated that the friction-reducing ability and antiwear property of the oil were both remarkably improved by attapulgite/La₂O₃ nanocomposite. A tribofilm mainly composed of Fe, Fe₃C, FeO, Fe₂O₃, FeOOH, SiO, SiO₂ and organic compound was formed on the rubbing surface under the lubrication of oil with attapulgite/La₂O₃ nanocomposite. The tribofilm possess excellent self-lubricating ability and mechanical properties, which is responsible for the reduction of friction and wear.

Attapulgite is a layered silicate with good friction-reduction and self-repairing properties.

[Determination of Voriconazole in Human Plasma and Its Bioequivalence by HPLC-MS/MS]

OBJECTIVE

To develop a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for the determination of voriconazole in human plasma and its bioequivalence.

METHODS

48 healthy male volunteers received a single dose of 200 mg voriconazole tablets in a two period (with two preparations) and randomized crossover bioequivalence study. Their plasma voriconazole was determined using HPLC-MS/MS. The pharmacokinetic parameters and bioequivalence of the two preparations were calculated with WinNonlin^®6.1.

RESULTS

The calibration curve of voriconazole ranged from 1 to 5 000 ng/mL. The HPLC-MS/MS method had less than 11% intra- and inter-day relative standard deviation (RSD),with 100.00% to 109.73% accuracies. The RSD of the matrix effect of voriconazole adjusted with internal standard was less than 15%. The extract recoveries exceeded 50% with good stability. The 90% confidence intervals for the peak concentration (C_max) and the area under the curve (AUC_0-t and AUC_0-∞)of voriconazole fell into the bioequivalence range of 80.00%-125.00%. There was no significant difference in peak time (T_max) between the two preparations.

CONCLUSION

HPLC-MS/MS can be used for determination of voriconazole in human plasma. The two tested preparations of voriconazole are bioequivalent.

[LC-MS/MS Determination of Tenofovir in Human Plasma and Its Bioequivalence]

OBJECTIVE

To develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detecting tenofovir in human plasma.

METHODS

Twenty four healthy male volunteers received a single oral dose of 300 mg tenofovir disoproxil fumarate tablets under fasting and high-fat diet conditions in a randomized four-way crossover bioequivalence study with two preparations of tablets. Plasma samples were taken and analyzed using the LC-MS/MS method. The pharmacokinetic parameters of the two preparations were calculated and compared statistically to evaluate their bioequivalence using Phoenix Winnonlin6.3.

RESULTS

Linear detection responses were obtained for tenofovir at the range from 3.13 to 500 ng/mL. The intra- and inter-day precisions were high,with lower than 5.43% [relative standard deviation (RSD)%],high recovery and good stability. The 90% confidence intervals of peak concentration (C_max) of tenofovir and its area under the curve (AUC_0-t and AUC_0-∞ ) all fell within the bioequivalence limit 80.00%-125.00% under both fasting and high-fat diet conditions. No significant difference in peak time (_Tmax) was demonstrated between the two preparations (P>0.05) .

CONCLUSION

The LC-MS/MS method can be used for simultaneous determination of tenofovir in human plasma. The two preparations of tablets are bioequivalent.

Tribological properties of synthetic base oil containing polyhedral oligomeric silsesquioxane grafted graphene oxide

The dispersion of graphene-based materials in lubricating oil is a prerequisite for improving its friction and wear performance. In this study, polyhedral oligomeric silsesquioxane (POSS) grafted graphene oxide (GO) was synthesized with an aim to improve the dispersibility of graphene in synthetic base oil. The composition and morphology of POSS-GO conjugates were characterized by FTIR, XPS, Raman spectroscopy, TEM and SPM. The tribological behavior of base oil with various concentrations of POSS-GO were examined using a UMT-3 friction and wear tester, and the worn surfaces were analyzed using Raman spectroscopy. It was found that concentrations of POSS-GO additives in the base oil is an important aspect for decreasing the friction and wear of the lubricated solid contacts. At lower and higher concentrations of POSS-GO, the lubricating effect is not effective or even worse. In contrast, at optimized concentration of POSS-GO, graphene sheets could form a boundary tribofilm between the contact, resulting in reduction of the friction coefficient and wear.

The dispersion of graphene-based materials in lubricating oil is a prerequisite for improving its friction and wear performance.

Is it Beneficial to Reuse the Balloon in Percutaneous Kyphoplasty for the Treatment of Non-Neoplastic Vertebral Compression Fractures?

BACKGROUND Percutaneous kyphoplasty (PKP) has been widely used to treat vertebral compression fractures (VCFs). Bilateral percutaneous punctures are always performed to access the fractured vertebrae. However, the procedure has expensive clinical costs, especially the cost for the device, which creates a heavy financial burden for patients. MATERIAL AND METHODS Data from 49 patients who have single-level non-neoplastic vertebral compression fracture (VCF) were collected for 12 months after treated by PKP, including 21 cases that used bilateral puncture with single balloon (S group) and 28 cases that used bilateral puncture with double balloon (D group). We assessed the clinical (visual analogue scale, VAS) and radiological (vertebral height and kyphotic angle, KA) outcomes. Cost data (gross medical cost, cost for the device and cost for drugs) were obtained from the medical bill of each patient. RESULTS Baseline patient variables were similar between the two groups except the compensation (S group <D group). No severe cement leakage and only one adjacent-level fracture were observed during the follow-ups. Each group showed significant improvements in the VAS, anterior height (AH) of vertebral body and KA after PKP, while no significant differences were observed when the VAS, vertebral height, and KA at the same time were compared between the S group and the D group. Costs in the S group were significantly lower than those in the D group. CONCLUSIONS Both single balloon and double balloon bilateral puncture PKP are relatively safe and efficient in non-neoplastic VCFs. However, reuse of the balloon in PKP can decrease the costs.

Enhanced Photoelectrochemical Performance in Reduced Graphene Oxide/BiFeO3 Heterostructures

BiFeO₃ (BFO)-based ferroelectrics have been proved to be visible-light-driven photoelectrodes for O₂ production. However, the hitherto reported photoelectrochemical performances remain inferior to meet the requirements for any applications. Besides, expensive noble metals (Ag, Au) are commonly required to achieve high photoelectric conversion efficiency. Here, the significant enhancements of photoelectrochemical performance is reported by fabricating a noble-metal-free reduced graphene oxide (RGO)/BFO composite film via a simple and cost-effective solution process. The optimized RGO/BFO composite film exhibits a 600% improvement of the short-circuit photocurrent density compared to that of the pristine BFO, and also outperforms the noble-metal/BFO cells under the same reaction conditions. Furthermore, the incident photon-to-current efficiency of the optimized RGO/BFO sample shows threefold enhancement. This study delivers a facile and low-cost approach to preparing 2D materials/ferroelectric heterostructures and offers a promising pathway to boost the performance of semiconducting ferroelectric photoelectrodes.

[Determination of Warfarin Enantiomers in Human Plasma with HPLC-MS/MS]

OBJECTIVE

To establish a high performance liquid chromatography-mass spectrometry/mass spectrometry (HPLC-MS/MS) method for determination of warfarin enantiomers in human plasma.

METHODS

Warfarin enantiomers were extracted with ethyl acetate. The HPLC-MS/MS method used naproxen as internal standard, with methanol : water : formic acid = 85 : 15 : 0.05 as mobile phase, at a flow rate of 0.18 mL/min. R-warfain, S-warfarin and internal standard (IS) were separated on column MS Chiral MS-OD (50 x 2.1 mm, 3 μm). Warfarin enantiomers were protonated with electroapry ionization (ESI) in negative electron ionization mode. The ion pairs being detected were (m/z) 307.2-160.9 (R-warfain and S-warafrin) and (m/z) 228.9 --> 185.1 (IS).

RESULTS

The within-run precision relative standard deviations (RSD) and between-run precision RSD of R-warfarin were 3.2%-5.8% and 2.5%-5.1%, respectively. The method recoveries and extraction recoveries of R-warfarin were (96.1 ± 5. 6)%-(105.4 ± 4.7)% and 80.7%-84.4%, respectively. The matrix effect RSD was less than 10%. The within-run precision RSD and between-run precision RSD of S-warfarin were 3.7%-5.2% and 3.2%-4.8%, respectively. The method recoveries and extraction recoveries of 5-warfarin were (98.3 ± 5.1)%-(103.7 ± 3.8)% and 81.3%-84.6%, respectively. The limit of quantification was 0.1 μg/mL for both analytes.

CONCLUSION

This new method is fully validated with satisfactory accuracy and adequate reproducibility. Therefore, it can be applied for separating and detecting plasma warfarin enantiomers.

[Bioequivalence of Ubenimex Capsules in Healthy Volunteers]

OBJECTIVE

To evaluate bioequivalence of two specifications of ubenimex capsules in comparison with the Japanese branded product (R).

METHODS

The study adopted a 3-way crossover design in twenty-four healthy male volunteers, whose plasma concentrations of ubenimex were determined by UPLC-MS/MS after administration a single oral dose of 30 mg of domestic ubenimex T1 (10 mg/capsule), T2 (30 mg/capsule) and branded ubenimex R (30 mg/capsule) sequentially. The bioequivalence was evaluated using WinNonlin6. 1 statistical analysis software.

RESULTS

One volunteer was excluded because of failure to follow medication instructions. The main pharmacokinetic parameters of ubenimex of T1, T2 and R were as follows: C(max) (2 646.73 ± 454.09) ng/mL, (2 675.91 ± 474.32) ng/mL and (2 432.79 ± 544.32) ng/mL, respectively; T(max) (0.68 ± 0.23) h, (0.76 ± 0.19) h and (0.77 ± 0.26) h, respectively; AUC(0-t) (3 925.23 ± 478.34)(ng x h)/mL, (3 804.62 ± 448.84)(ng x h)/mL and (3 789.30 ± 443.15)(ng x h)/mL, respectively; AUC(0-∞)(3 938.31 ± 479.54)(ng x h)/mL, (3 817.26 ± 450.90) (ng x h)/mL and (3 800.90 ± 444.77) (ng x h)/mL, respectively; CL/F (7.72 ± 0.92) L/h, (7.97 ± 0.98) L/h and (7.99 ± 0.90) L/h, respectively; Vd (26.08 ± 9.20 )L, (25.65 ± 10.22) L and (26.03 ± 10.05) L, respectively. The relative bioavailability F(0-t) and F(0-∞) of T1 and T2 against the branded preparation R were (103.90 ± 9.19)% and (100.77± 9.36)%, and (103.93 ± 9.20)% and (100.79 ± 9.33)%, respectively.

CONCLUSION

Both ubenimex capsules T1 and T2 are bioequivalent to the Japanese branded products.

Construction of a novel inducing system with multi-layered alginate microcapsules to regulate differentiation of neural precursor cells from bone mesenchymal stem cells

Neural precursor cells (NPCs) are a promising cell source for the treatment of nervous system diseases; however, they are limited in their applications due to source-related ethical considerations or legislations. Therefore, a novel approach is necessary to obtain sufficient NPCs. Recently, the usage of bone marrow-derived mesenchymal stem cells (BMSCs) differentiated into neural cells has become a potential method to obtain NPCs. Moreover, growth factors (GFs) are emerging as inducers to evoke the differentiation of BMSCs into NPCs. For example, GFs may activate various signaling pathways related to neural differentiation, such as phosphatidylinositol 3 kinase/protein kinase B, cyclic adenosine monophosphate/protein kinase A, and Janus kinase/signal transducer activator of transcription. However, the utilization of growth factors still has some limitations such as high costs and low rates of neural differentiation. Neuroblastoma cells have been characterized as a potential pool for growth factors. Additionally, basic fibroblast growth factor (bFGF), a type of growth factor, has been demonstrated to be able to increase the differentiation and survival rate of NPCs. For better use of neuroblastoma cells and bFGF, we established a novel system involving multi-layered alginate-polylysine-alginate (APA) microcapsules to encapsulate neuroblastoma cells and bFGF, which may not only provide sufficient growth factors in a sustained manner but also avoid the carcinogenicity caused by neuroblastoma cells. Above all, we hypothesized that neuroblastoma cells and bFGF encapsulated in multilayered alginate microcapsules may efficiently induce the differentiation of BMSCs into NPCs.

A Subspace Semi-Definite programming-based Underestimation (SSDU) method for stochastic global optimization in protein docking

We propose a new stochastic global optimization method targeting protein docking problems. The method is based on finding a general convex polynomial underestimator to the binding energy function in a permissive subspace that possesses a funnel-like structure. We use Principal Component Analysis (PCA) to determine such permissive subspaces. The problem of finding the general convex polynomial underestimator is reduced into the problem of ensuring that a certain polynomial is a Sum-of-Squares (SOS), which can be done via semi-definite programming. The underestimator is then used to bias sampling of the energy function in order to recover a deep minimum. We show that the proposed method significantly improves the quality of docked conformations compared to existing methods.

Edaravone promotes functional recovery after mechanical peripheral nerve injury

Edaravone has been shown to reduce ischemia/reperfusion-induced peripheral nerve injury. However, the therapeutic effect of edaravone on peripheral nerve injury caused by mechanical factors is unknown. In the present study, we established a peripheral nerve injury model by crushing the sciatic nerve using hemostatic forceps, and then administered edaravone 3 mg/kg intraperitoneally. The sciatic functional index and superoxide dismutase activity of the sciatic nerve were increased, and the malondialdehyde level was decreased in animals in the edaravone group compared with those in the model group. Bcl-2 expression was increased, but Bax expression was decreased in anterior horn cells of the L_4-6 spinal cord segments. These results indicated that edaravone has a neuroprotective effect following peripheral nerve injury caused by mechanical factors through alleviating free radical damage to cells and inhibiting lipid peroxidation, as well as regulating apoptosis-related protein expression.

[Determination of dimemorfan in human plasma and urine with HPLC-MS/MS]

OBJECTIVE

To develop a sensitive and reproducible HPLC-MS/MS method for analyzing dimemorfan in human plasma and urine.

METHODS

Dimemorfan was extracted from plasma and urine by redistilled ether, with lidocaine serving as the internal standard (IS). The analysis was performed on a column of ultimate C18 (50 mm x 4.6 mm, 5 microm) with the mobile phase consisting of methyl alcohol-water-formic acid = 75:25 : 0.05 at a flow rate of 0. 2 mL/min. Dimemorfan was detected by API 3000 mass spectrometer, with multiple reaction monitoring after protonated with ESI in positive electron ionization mode. The ion pairs being detected were (m/z) 256.4-->155. 3 (dimemorfan) and 235.4-->86.1 (lidocaine), respectively.

RESULTS

The regression equation for dimemorfan showed excellent linearity (r = 0.995 7) from 0. 025 to 5.0 ng/mL of plasma with detecting limitation of 0.025 ng/mL and perfect linearity (r = 0.9983) from 0.1 to 20.0 ng/mL of urine with detecting limitation of 0.1 ng/mL. The method recoveries of dimemorfan in plasma and urine were ranging from 103.38% to 106.88% and 90.05% to 101.40%, respectively. The maximum intra-day and inter-day relative standard deviations (RSD) of concentration of dimemorfan were 5.92% and 5. 70% (for plasma), 10.35% and 8.80% (for urine), respectively.

CONCLUSION

This new method was validated to be accurate and sensitive to determinate the concentration of dimemorfan in plasma and urine samples, and can be applied for pharmacokinetic studies of dimemorfan.

[Pharmacokinetics study of amoxicillin sodium clavulanate potassium (10:1) injection in healthy volunteers]

OBJECTIVE

To study the pharmacokinetics of amoxicillin sodium clavulanate potassium (10:1) injection with different single doses intravenous infusion and one dose repeated intravenous injection in healthy volunteers for guiding the rational clinical regimen.

METHODS

Using infusion pump constantly intravenous dripping in 30 min, 4 mL blood samples were collected before and after the administration at 10 min, 20 min, 30 min, 45 min, and 1, 1.25, 1.5, 2, 2.5, 3, 4, 6, 8, 10 h. The plasma concentrations of amoxicillin and clavulanate were detected by high performance liquid chromatography- mass spectrometry/mass spectrometry method. The pharmacokinetic parameters were calculated by DAS2.0.1 software.

RESULTS

The dispositions of amoxicillin and clavulanate matched three or two compartment model with the weight coefficient 1/cc. To avoid the biases caused by compartment model fitting, the pharmacokinetic parameters were statistical moment parameters of non-compartment model. The peak concentrations, the areas under curve, the half-lifes and the clearances after single injections of 0. 55 g, 1.1 g and 2.2 g indicated that both amoxillin and clavulanate had linear dynamics characteristics. After 1.1 g single dose and multiple doses infusion, the pharmacokinetic parameters of amoxicillin and clavulanate were close respectively, and the trough concentrations before the 7th to 13th administration were lower than the detection limitation, which implied that the previous administration had cleared out before the next administration, and no accumulation happened after multiple doses.

CONCLUSIONS

The amoxicillin sodium clavulanate potassium (10:1) injection possesses the linear kinetics. The dosage regimen of 1.1 g Q8h intravenous infusion could meet the needs of clinical therapy.

[Heterogeneous characteristic of PAHs' spatial distribution in a large coking site of China]

A large coking contaminated site was selected to study the PAHs' spatial distribution probability in surface-soil (0-50 cm) through the indicator kriging of the non-parametric geostatistics, and the map of probability distribution with a contaminant target was plotted over the entire site. Results indicated that the indicator semivariograms were stable after the conversion of sample data, but the poor correlation of spatial samples was observed due to the spatial variability. In this site, the distribution of the contamination probability of four PAHs' showed a similar characteristic, and the areas with a probability of more than 45% were mainly distributed in production process workshops for coking, gas purification, tar products etc, of the central, northwest and southeast site with serious contamination, while the areas with a probability of less than 45% were mainly distributed in coal preparation, gas purification workshops of the southwest and northeast site. Based on the above analysis results, we can draw a conclusion that the forecast probability results are consistent with the occurrence and distribution of pollution sources, which is important for defining the remediation boundary and calculating the contaminated soil volume.

[Pharmacokinetics of injected cefozopran hydrochloride in healthy volunteers]

OBJECTIVE

To study the pharmacokinetics of injected cefozopran hydrochloride in healthy volunteers.

METHODS

24 healthy volunteers were enrolled to receive low (0.5 g), middle (1.0 g), high (2.0 g) doses of single injection and multiple doses (1.0 g) injection of cefozopran hydrochloride in an open randomized study. The plasma concentrations of cefozopran were determined by RP-HPLC. The DAS2.0 was used to fit the concentration-time data and to calculate the pharmacokinetic parameters.

RESULTS

The main pharmaeokinetic parameters for a single injection of low, middle and high doses of cefozopran were as follows: Cmax (48.27 +/- 9.84), (77.99 +/- 15.08) and (171.59 +/- 18.27) mg/L; Tmax (0.50 +/- 0.00), (0.51 +/- 0.02) and (0.51 + 0.02) h; AUCo-t (92.43 +/- 24.02), (152.45 +/- 16.26) and (341.03 +/- 44.16) mg x h/L; t1/2beta (1.97 +/- 0.19), (2.44 +/- 0.24) and (2.18 +/- 0.31) h, respectively. The main pharmacokinetic parameters for a multiple doses injection of cefozopran were as follows: Cmax (80.39 +/- 11.86) mg/L; Tmax (0.51 +/- 0.02) h; AUCo-t (159.74 +/- 15.06) mg x h/L; t1/2beta (2.55 +/- 0.55) h. The accumulative rate of cefozopran through urine pathway within 24 h was (89.4 +/- 15.5)%. The statistical analysis showed that Cmax, AUCo-t, and AUCo-infinity increased significantly with increased doses of injection (P < 0.05). Those parameters were linearly correlated with the doses of injection (r = 0.9950, 0.9960, 0.9963). However, dosage did not have an impact on other pharmacokinetic parameters (P > 0.05). No gender differences in the parameters were found (P > 0.05).

CONCLUSION

Cefozopran hydrochloride performs a linear kinetics in healthy volunteers. The main pharmacokinetic parameters have no significant gender differences, and there is no drug accumulated with multiple doses of injection.

[Determination of donepezil enantiomer in human plasma by normal-HPLC-MS/MS]

OBJECTIVE

To develop and validate a normal phase HPLC-MS/MS method for the determination of donepezil enantiomer in human plasma.

METHODS

Donepezil was extracted from plasma by n-hexane:isopropanol (98:2, V/V) with lidocaine serving as an internal standard. The analytes went through the column of CHIRALCEL OJ-H (250 mm x 4.6 mm, 5 microm) with mobile phase n-hexane:n-propanol:diethylamine (60:40: 0.1, V/V/V). Donepezil enantiomer was determined by API 3000 in MRM mode.

RESULTS

The retention time of S-DN and R-DN were 15.56 min and 18.41 min, respectively. The calibration curves were linear in a range from 0.051 to 7.596 ng/mL for S-DN, and from 0.049 to 7.404 ng/mL for R-DN, respectively, both with more than 0.99 correlation coefficients. The relative recovery were 95.10%-103.70% for S-DN and 93.58%-98.00% for R-DN, respectively; the pretreatment recovery were 58.42%-61.08% for S-DN and 53.24%-61.87% for R-DN, respectively; the within-day RSD ranged from 8.35% to 11.28% for S-DN and from 6.78% to 11.58% for R-DN, respectively; the between-day RSD ranged from 5.82% to 9.02% for S-DN and from 6.87% to 9.19% for R-DN, respectively.

CONCLUSION

This normal phase HPLC-MS/MS method is simple, rapid, sensitive and accurate for the determination of donepezil enantiomer in human plasma and is suitable for pharmacokinetic studies of donepezil enantiomers.

[Determination of probucol in human plasma by HPLC-MS/MS]

OBJECTIVE

To develop a specific and sensitive method for the determination of probucol in human plasma using HPLC-MS/MS technique.

METHODS

Probucol were extracted from plasma by ethyl ether: dichloromethane (1:1, V/V), with physcion as an internal standard. The analytes went through the column of ultimate CN (50 mm x 4.6 mm, 5 microm) with mobile phase acetonitrile: water: ammonia water = 97:3:0.05 (adjusted pH = 7.2 with formic acid). Probucol was analyzed with a negative mode. The ion pairs being detected were 515.5-->236.1 (probucol) and 283.0-->239.9 physcion, respectively.

RESULTS

The established method was able to determine probucol in human plasma over the range of 2.5-6000 ng/mL, with a method recovery ranging from 93.02% to 104.12%. The intra and inter day variances were below 4.67% and 5.72%.

CONCLUSION

The HPLC-MS/MS method for analyzing probucol was validated. It is sensitive and suitable for pharmacokinetic studies of probucol.

[Determination of ubenimex in human plasma by HPLC-MS/MS]

OBJECTIVE

To establish a liquid chromatography tandem mass spectrometry method for the determination of ubenimex in human plasma.

METHODS

The essay was conducted with an API 3000 HPLC-MS/MS system consisted of a Ultimate C18 column (50 mm x 4.6 mm, 5 microm). The mobile phase consisted of methanol-water-formic acid (70 : 30 : 0.05, V/V/V) at a flow rate of 0.2 mL/min. Granisetron was used as the internal standard. The sample was extracted by solid phase extraction column and was operated under the multiple reaction monitoring mode using the electrospray ionization technique in positive mode.

RESULTS

The linear range of ubenimex was 0.4-4000 ng/mL. The limit of quantity was set at 0.4 ng/mL. The within-day and between-day variations were less than 6%.

CONCLUSION

This method for the quantitative determination of ubenimex was proved to be accurate, sensitive, selective and convenient and can be applied in the determination of ubenimex in human plasma.

[Determination of biapenem in human plasma by high performance liquid chromatography]

OBJECTIVE

To establish a method to determine biapenem in human plasma with high performance liquid chromatography.

METHODS

Chromatographic separation was performed on a YMC-C18 column (150 mmX 4. 6 mm, 5 microm) eluted with a mobile phase comprising 98 : 2 (V = V) of sodium acetate (0.1 mol/L, adjust with acetic acid to pH 4.5) and acetonitrile with a flow rate of 1.0 mL/min. The detection wavelength was set at 300 nm. Temperature was controlled at 35 degrees C. The plasma samples were precipitated with acetonitrile. The supernatant was vortexed with dichloromethane and 0.03 mL of the aqueous layer was injected for analysis.

RESULTS

The method was valid to detect biapenem in a range of 0.0625 mg/L to 80 mg/L (correlation coefficient 0.999). The pretreatment recovery of biapenem ranged from 96.11% to 98.76%. The methodological recovery of biapenem ranged from 99.14% to 109.69%. The inter-day RSD ranged from 0.92% to 2.79%. The intra-day RSD ranged from 2.46% to 4.08%. Less than 7% change of results was observed after the sample was stored in room temperature for 5 h, frozen and defrozen 3 times, stored at -30 degrees C for 28 d, stayed in autosampler for 24 h, and injected twice.

CONCLUSION

The method is sensitive, accurate and easy to perform, which offers a satisfactory tool for the determination and pharmacokinetic study of biapenem.

[Determination of nicacid and its metabolites in human plasma by HPLC-MS/MS]

OBJECTIVE

To develop a sensitive HPLC-MS/MS method for the determination of nicacid and its metabolites in human plasma.

METHODS

The assay was conducted with an API 3000 LC-MS/MS system comprising of a Genimi C18 column (50 x 3.00 mm, 3 microm), and an eluate of 0.1% acetic acid-methanol-isopropyl alcohol (98: 1:1), and flow rate was 0.2 mL/min. Acetonitrile was used to precipitate protein from the plasma samples. The loading samples contained the residue from the supernatant that were dissolved in the eluate solution and rinsed by dichloromethane was used as the loading samples. The ion pairs of m/z 124.1-->80.0, m/z 123.1-->80.0, m/z 181.1-->135.0 and m/z 138.1-->92.0 were used to quantify nicacid, niacinamide, nicotinuric acid and 6-methyl nicotinic acid (IS), respectively.

RESULTS

The standard curves of nicacid, niacinamide and nicotinuric were linear in the range of 1.25-320 microg/L, 1.25-1280 microg/L and 1.25-1280 microg/L, respectivly. All with a low determination limits of 1.25 microg/L and a less than 9% within-day and inter-day RSD. The recovery rates reached 89% to 105%.

CONCLUSION

The method is simple, rapid, sensitive, and suitable for the determination of nicacid and its metabolites in human plasma.

[Determination of lidocaine and its metabolites in human plasma by liquid chromatography in combination with tandem mass spectrometry]

OBJECTIVE

To establish a liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method for the determination of lidocaine (LDC) and its metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX), in human plasma. METHODS; The assay was conducted with an API 3000 HPLC-MS/MS system consisted of a Ultimate C18 column (50 x 4.6 mm, 5 microm). The mobile phase consisted of methanol: 5 mmol/ L ammonium acetate (50:50, pH was adjusted to 5.0 by formic acid) and the flow rate was set at 0.2 mL/min. The alkalinized sample was extracted with ethyl acetate. After evaporation of the organic layer, the residue was dissolved in mobile phase and the drug was determined by HPLC-MS/MS using electrospray ionization.

RESULTS

The calibration curve was linear in a range from 15.625 to 2000 ng/mL for LDC. Linear calibration curves were obtained in the range of 1.5625 to 200 ng/mL for both for MEGX and GX. The limit of quantification for LDC, MEGX and GX was set at 15.625, 1.5625 and 1.5625 ng/mL.

CONCLUSION

This method for the quantitative determination of lidocaine and its metabolites in human plasma is simple, rapid, sensitive and accurate. Therefore it can be used for the determination of lidocaine and its metabolites in clinical practice.

[Detecting penehyclidine hydrochloride in rats plasma and tissues with HPLC-MS/MS]

OBJECTIVE

To develop a method for detecting penehyclidine hydrochloride (PH) in mouse plasma and tissues using HPLC-MS/MS.

METHODS

The plasma and tissue samples were extracted with petroleum ether, ethyl ether (70:30). The isolation of PH was achieved on an Allure C18, (50 x 2.1 mm, 5 microm) column, with methanol/5 mmol/L ammonium acetate/triethylamine = 90/10/0.05 (adjusted pH 5.8 by formic acid as mobile phase. Benzhydramine was used as the internal standard.

RESULTS

The calibration curves were linear over the range of 0.39-200 ng/mL for plasma and 0.391-100 ng/mL for tissues. The extraction recovered 67.32-70.80% of PH in plasma, 84.99%-89.27% of PH in lung tissues, and 76.86%-81.98% of PH in brain tissues. The HPLC detected 97.66%-99.97% of PH in extracted samples of plasma, 96.55%-101.65% extracted samples of lung and 95.18%-100.21% of extracted samples of brain. The within-day RSD were 1.94%-2.93%, 1.73%-3.70% and 2.35%-2.79% for plasma, lung, and brain, respectively. The between-day RSD were 3.00%-3.85% 2.86%-3.94% and 2.77%-5.00% for plasma, lung, and brain, respectively. Both the long-term and freeze-thaw stabilities were acceptable. The long-term RSD were 1.52%-5.26%, 1.88%-2.93%, and 2.22%-3.76% for plasma, lung, and brain, respectively. The freeze-thaw RSD were 0.38%-3.55%, 2.79%-9.60%, and 1.35%-2.29% for plasma, lung, and brain, respectively.

CONCLUSION

The assay is simple and accurate, with good reproducibility, and can satisfy to the needs of pharmacokinetics and relative bioavailability studies on penehyclidine hydrochloride.

[Pharmacokinetics and relative bioavailability study of roxithromycin tablet in Chinese healthy volunteers by LC-MS/MS]

This is a study of assessing the comparative bioavailability of roxithromycin produced by two companies in 36 healthy volunteers. On the basis of informed consent, 36 healthy male volunteers received each medicine at the roxithromycin dose of 150mg in a cross-over study. There was a 1-week washout period among the doses. Plasma concentrations of roxithromycin were monitored by an LC-MS/MS for over a period of 72 hours after administration. In this study, roxithromycin was generally well tolerated. After an oral administration of roxithromycin capsule, the pharmacokinetic parameters of roxithromycin, such as AUC(0-72 h) (66 076 microg x L x h(-1) and 70 334 microg x L x h(-1) for test and reference capsule, respectively) and AUC(0-infinity) (68 153 microg x L x h(-1) and 72 362 microg x L x h(-1)) were significantly similar. For test and reference capsule, the values of C(max) were 6 631.5 microg x L(-1) and 7 033.9 microg x L(-1) respectively, of T1/2 were 15.39 +/- 4.61 h and 16.06 +/- 5.56 h, and of T(max) were 1.3 +/- 0.9 h and 1.4 +/- 0.7 h respectively. The relative bioavailability F was 94.9% +/- 22.4% of tested formulation. The values of 90% confidence interval around the ratios (test/reference) (obtained by analysis of variance, ANOVA) were 88.3%-101.2% for C(max), 86.2%-98.9% for AUC(0-72) h, being within the predefined acceptable range for the conclusion of bioequivalence. The results of statistical analysis suggest that the two formulations be bioequivalent.

[Determination of lovastatin and its active metabolites in human plasma with high performance liquid chromatography-tandem mass spectrometry]

OBJECTIVE

To develop a sensitive LC-MS/MS method for analyzing lovastatin and its active metabolites lovastatin acid in human plasma.

METHODS

Lovastatin and lovastatin acid were extracted from plasma by ethyl ether -dichloromethane (V/V, 1:1), with simvastatin serving as an internal standard. The analytes went through the column of Phenomenex Gemini C18 (50 x 3 mm, 3 microm) with mobile phase acetonitrile-water (85:15), and was analyzed by API3000 after protonated with ESI mode. The ion pairs being detected were 427.4-->325.4, 445.4-->343.4 and 436.4-->325.4, respectively.

RESULTS

The established method was able to determine lovastatin in human plasma over the range of 0.03125-64 microg/L, with recovery rates ranging from 96% to 102%. The intra and inter day variances were below 9.3%.

CONCLUSION

The LC-MS/MS method for analyzing lovastatin is validated and is suitable for clinical pharmacokinetic studies.

Simultaneous determination of the 10 major components of Da-Cheng-Qi decoction in dog plasma by liquid chromatography tandem mass spectrometry

A liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of the 10 major components of Da-Cheng-Qi decoction (rhein, emodin, aloe-emodin, chrysophanol, rheochrysidin, naringin, naringenin, hesperidin, magnolol and honokiol) in dog plasma. Plasma samples were spiked with internal standard (ibuprofen), acidified with HCl and extracted twice by liquid-liquid extraction using ethyl acetate. Separation was performed on a YMC-Pack ODS-A C(18) column (5 microm, 150 mm x 4.6 mm) and a C(18) guard column (5 microm, 4.0 mm x 2.0 mm) with methanol-water (92:8, v/v) at a flow rate of 0.3 mL/min. The LC/MS system was operated under the multiple reaction monitoring mode using electrospray ionization in the negative ion mode. All analytes showed good linearity over a wide concentration range (r>0.99). The linear range of the calibration curves was 5000-19.53 ng/mL for rhein; 400-3.13 ng/mL for emodin; 800-3.13 ng/mL for aloe-emodin, chrysophanol, naringin, naringenin, hesperidin, magnolol and honokiol; 160-0.63 ng/mL for rheochrysidin. The lower limit of quantification was: 19.53 ng/mL for rhein; 3.13 ng/mL for emodin, aloe-emodin, chrysophanol, naringin, naringenin, hesperidin, magnolol and honokiol; 0.6 3 ng/mL for rheochrysidin. The overall mean accuracy for the 10 major components of Da-Cheng-Qi decoction was 90.40-108.60%. Intra-day and inter-day precision was < or =12.43% and < or =11.32%, respectively. We conclude that this method is appropriate for simultaneous determination of the 10 major components of Da-Cheng-Qi decoction in dog plasma and the investigation of the pharmacokinetics of Da-Cheng-Qi decoction in dog.