Evaluation genotoxicity of acetylnerolin based on quantitative structure-activity relationship model and in vitro tests / 中国药理学与毒理学杂志

OBJECTIVE To evaluate the genotoxicity of naproxen (NPX) impurities acetylnerolin (Ace). METHODS The genotoxicity of Ace was predicted by ADMET, Derek and Sarah with the quanti?tative structure-activity relationship (QSAR). The chromosomal aberration and bacterial reverse-muta?tion (Ames) tests were performed to verify the above results. In chromosomal aberration tests, CHL cells were incubated with Ace 10, 20 and 40 mg · L-1 for 4 h in the presence or absence of metabolic activation system solution (S9 mix). Methyl methane sulfonate (MMS) 20 mL · L-1 without S9 mix and cyclophosphamide (CP) 12 mg · L-1 with S9 mix served as positive control. The number of chromo?somes in each aberrant metaphase (including fissure, exchange, ring, break and polyploid) was counted and recorded, when the distortion rate less than 5％was considered negative and more than 10％was considered positive. In Ames test, the potential mutagenicity was evaluated using five strains of S. typhimurium ( TA97,TA98,TA100,TA102 and TA1535). They were treated with Ace 5, 25, 125 and 625μg per plate with or without S9 mix and incubated for 48-72 h. When without S9 mix, Dexon 50μg per plate served as positive control for TA97 and TA98, MMS 2.0μL per plate served as positive control for TA100 and TA102, and sodium azide 1.5μg per plate served as positive control for TA1535. When with S9 mix, 2-AF 100 μg per plate served as positive control for TA97, TA98 and TA100, 1, 8-dihydroxyanthraquinone (100μg per plate) served as positive control for TA102 and CP 50μg per plate served as positive control for TA1525. When the number of colonies was at least two-fold that of the negative control, the compound was considered mutagenic. RESULTS Although the Derek and Sarah software predicted that the NPX impurities were not genotoxic, ADMET data showed that Ace could induce chromosomal aberrations. The distortion rate of Ace 40 mg · L-1 was greater than 5％, but less than 10％. The distortion rate of Ace was less than 5％when<20 mg·L-1. Consistent with the results of ADMET, Ace might induce chromosomal aberrations. Ames test results showed that Ace did not signifi?cantly increase the number of bacteria (5-625μg per plate) compared with the negative control. Contrary to the ADMET results, Ace had no mutagenicity. CONCLUSION Ace has potential chromosomal muta?genicity. For life-long usage of NPX, the content of Ace should be reduced from 0.15％of conventional impurities to 0.015％.

A hepatoprotection study of Radix Bupleuri on acetaminophen-induced liver injury based on CYP450 inhibition / 中国天然药物

We investigated the potential hepatoprotective effect of Radix Bupleuri (RB) by inducing acute liver injury (ALI) in an animal model using acetaminophen (APAP) after pretreatment with RB aqueous extract for three consecutive days. Compared to those of the APAP group, the biochemical and histological results of the RB pretreatment group showed lower serumaspartate transaminase (AST) and alanine transaminase (ALT) levels as well as less liver damage. Pharmacokinetic study of the toxicity related marker acetaminophen-cysteine (APC) revealed a lower exposure level in rats, suggesting that RB alleviated APAP-induced liver damage by preventing glutathione (GSH) depletion. The results of cocktail approach showed significant inhibition of CYP2E1 and CYP3A activity. Further investigation revealed the increasing of CYP2E1 and CYP3A protein was significantly inhibited in pretreatment group, while no obvious effect on gene expression was found. Therefore, this study clearly demonstrates that RB exhibited significant protective action against APAP-induced acute live injury via pretreatment, and which is partly through inhibiting the increase of activity and translation of cytochrome P450 enzymes, rather than gene transcription.

Metabonomic profiling of plasma metabolites in Wistar rats to study the effect of aging by means of GC/TOFMS-based techniques / 药学学报

The global metabolite profiles of endogenous compounds of Wistar rats from 12 to 20 weeks old were investigated to take deep insight into and get better understanding of the pathogenesis of development and aging. Plasma from Wistar rats at 12, 14, 16, 18, and 20 weeks old were analyzed using GC/TOFMS. Multivariate data analysis was then used to process the metabonomic data which indicated excellent separation between different weeks and showed that the metabolic profiles of the samples changed with age, enabling age-related metabolic trajectories to be visualized. Decreased concentrations of citric acid, cis-aconitic acid, 9-(z)-hexadecenoic acid along with increased levels of hexanedioic acid, alpha-tocopherol, 3-indole propionic acid, etc contributed to the separation. Several major metabolic pathways were identified to be involved in metabolic regulation. This suggests that GC/TOFMS-based metabonomics is a powerful alternative approach to identifying potential biomarkers and investigating the physiological developments of aging and it is important to employ suitable age-match control group in metabonomic study of physiological monitoring, drug safety assessment, and disease diagnosis, etc.

Separation and determination of donepezil hydrochloride enantiomers in plasma by capillary electrophoresis / 药学学报

<p><b>AIM</b>To establish chiral separation method for donepezil hydrochloride (E2020) enantiomers by capillary electrophoresis (CE) and determine the two enantiomers in plasma.</p><p><b>METHODS</b>Alkalized plasma was extracted by isopropanol-n-hexane (3 : 97) and L-butefeina was used as the internal standard. Enantioresolution was achieved using 2.5% sulfated-beta-cyclodextrin as chiral selector in 25 mmol x L(-1) triethylammonium phosphate solution (pH 2.5) on the uncoated fused-silica capillary column (70 cm x 50 microm ID). The feasibility of the method to be used as quantitation of E2020 enantiomers in rabbit plasma was also investigated.</p><p><b>RESULTS</b>E2020 enantiomers were separated at a baseline level under the above condition. The linearity of the response was evaluated in the concentration range from 0.1 to 5 mg x L(-1). The linear regression analysis obtained by plotting the peak area ratio (A(s)/A(i)) of the analyte to the internal standard versus the concentration (C) showed excellent correlation coefficient (r = 0.999 2 for R(-)-E2020, r = 0.999 7 for S(+)-E2020) and the equations were A(s)/A(i) = 0.024 2 + 0.289 2C and A(s)/A(i) = 0.010 8 + 0.273 7C, respectively. The low limit of detection was 0.05 mg x L(_1). The inter- and intra-day precision (RSD) were all less than 20% .</p><p><b>CONCLUSION</b>Compared with CSP by HPLC, the CE method is simple, reliable, inexpensive and suitable for studying the stereoseletive pharmacokinetics in rabbits.</p>

Determination of donepezil in human plasma by HPLC-MS / 药学学报

<p><b>AIM</b>To establish a sensitive and specific liquid chromatography-mass spectrometry (time-of-flight) [LC-MS (TOF)] method for the determination of donepezil in human plasma after an oral administration of 5 mg donepezil hydrochloride tablet.</p><p><b>METHODS</b>Alkalized plasma was extracted with isopropanol-n-hexane (3:97) and loratadine was used as internal standard. Solutes were separated on a C18 column with a mobile phase of methanol-acetate buffer (pH 4.0) (80:20). Detection was performed on a time-of-flight mass spectrometry equipped with an ESI interface and operated in positive-ionization mode. Donepezil quantitation was realized by computing the peak area ratio (donepezil-loratadine) (donepezil m/z 380[M + H]+ and loratadine m/z 383[M + H]+) and comparing them with calibration curve (r = 0.9998).</p><p><b>RESULTS</b>The linear calibration curve was obtained in the concentration range of 0.1-15 micrograms.L-1. The detection limit of donepezil was 0.1 microgram.L-1. The average recovery was more than 90%. The intra- and inter-run precision was measured to be below 15% of RSD.</p><p><b>CONCLUSION</b>The method is sensitive, simple and rapid, so, it can meet the need of the studies on the pharmacokinetics and bioavailability of donepezil.</p>