Latest ArticlesProtein arginine methyltransferase 5 (PRMT5) is an important type Ⅱ human methyltransferase. It catalyzes the symmetrical double-methylation of many histones and non-histones, and it is highly expressed in many kinds of tumors. PRMT5 has been proven to be a potential new target for cancer treatment. Based on the reported crystal complex of EPZ015666 with PRMT5, a series of new compounds was designed using GSK3326595 (EPZ015938) as the lead compound and using the conformational restriction approach. We found that compounds B8 and the C series of derivatives displayed enzyme inhibitory activity comparable to that of GSK3326595. Compounds C3 and C4 showed poor permeability in Caco-2 cells, and that might be one of the reasons for their poor anti-proliferative activity against Z-138 cells. These data provide insights for further structural optimization.
A UHPLC method for the simultaneous determination of multiple constituents in QingJinHuaTan Decoction was established. The separation was performed on a Waters cortecs T3 column (150 mm×2.1 mm, 1.6 μm); the mobile phase was acetonitrile-water (containing 0.04% phosphoric acid) with gradient elution at a flow rate of 0.30 mL·min-1, the column temperature at 25℃ and the wavelengths at 238 nm and 280 nm. The results showed that all peaks were well separated and all components had a good linear relationship in the investigative range, (r > 0.999). The repeatability and stability were good and the recovery was between 92.5%-104.7%. The method is simple, accurate and reliable and provides a basis for quality control of QingJinHuaTan Decoction and for further development of methods for its standardization.
A tadalafil analogue was detected during routine screenings from two "fatigue reliever, immunity enhancer" dietary supplements by using UHPLC/Q-TOF HRMS. The MS2 spectrum of this compound was almost identical to that of 2-hydroxypropylnortadalafil. However, the retention time of this analogue was different from that of the 2-hydroxypropylnortadalafil isomers. The analogue was purified by using preparative HPLC and the structure was elucidated by mass spectrometric and NMR spectroscopic experiments. The spectral data suggested that the analogue bore a 3-hydroxypropyl group instead of the N-methyl group in tadalafil. The structure was further confirmed by comparison of the 1H NMR spectra data with those of the reference standard, and thus named as 3-hydroxypropylnortadalafil. The structure is first reported in China.
Collagen is the main constituent of gelatinous Chinese medicine, with deer hide gelatin (Cervi Corii Colla, DHG) made from deer hide (DH) through a complex thermal and high-pressure processing procedure. During this procedure some amino acids in collagen undergo hydroxylation and deamidation. In the present study, comparative analysis of proteins and peptides in DH and DHG was carried out using "peptidomics-modifications" methods. Nano-LC-MS/MS was used to analyze proteins and peptides in DH and DHG, and the number and sites of modification were determined as well. The amount of hydroxylation and deamidation that occurred in DHG was significantly greater than that in DH, suggesting that under thermal and high-pressure processing these modifications occurred more frequently on certain amino acids in collagen, and might be correlated with hydrophobicity. The occurrence and mechanism of hydroxylation and deamidation in DH processing procedures should be explored in further research. The present study provides important evidence of the chemical constituents and the correlation of processing procedures with these modifications, and also suggests some investigative ideas for DHG processing optimization and improvement of quality standards.
To establish a method for the determination of polymer impurities in ceftazidime raw materials and preparations, a ceftazidime degradation solution containing polymer impurities was prepared by forced polymerization. Polymer impurities in the degradation solution were separated and identified by high performance gel chromatography and the column switching-LC-MSn method. A new RP-HPLC method for ceftazidime polymer was established and validated with a Phenomenex Gemini-C18 column using a mobile phase gradient elution of 0.02 mol·L-1 phosphate buffer, methanol and acetonitrile. The results showed that when using this high performance gel chromatography method some small molecular weight impurities were co-eluted with the polymers, resulting in a poor specificity and poor quantitative accuracy. But when using the RP-HPLC method, four polymer impurities were detected in the 25-45 min time range with good specificity, sensitivity and robustness, including two ceftazidime dimers, trimers, and derivatives. Therefore, the described RP-HPLC method is suitable for the quality control of polymer impurities in ceftazidime, and ceftazidime degradation solution can be used as suitable solution for analysis of ceftazidime polymers.
Ginsenoside Ro decreased measures of inflammation, aging, oxidants and thrombus formation in a previous study. To measure ginsenoside Ro content in red ginseng from different years, an optimized extraction method was developed to determine ginsenoside Rg1, Re, Rb1 and Ro content by HPLC in 43 batches of red ginseng from different origins, growing years and manufacturers. The results indicate that the best extraction method was to ultrasonify a 1 g sample in 70% methanol for 50 min. The total running time of the optimized gradient was 50 min using a C18 core-shell column and was half the time described in the Chinese Pharmacopoeia, 2015 edition. The separation resolution of all of targeted compounds was greater than 1.6. The peak shape of ginsenoside Ro was optimal when the mobile phase consisted of acetonitrile and water with 0.1% phosphoric acid. The content of ginsenoside Ro was in the range of 0.11% to 0.43%, and the average content was 0.26%, which was higher than that of ginsenoside Rg1 and Re. The ratio of ginsenoside Ro and Re as a threshold could be used to discriminate red ginseng from different growing years; in addition, 100%, 94.4% and 46.6% of red ginseng from six, five and four years exceeded the threshold of 1.3. Our optimized analytical method for characterization of red ginseng is convenient and shortens the assay time.
The dosage of asarum in Qing-Fei-Pai-Du decoction (QFPD) is twice the dosage prescribed by the Chinese Pharmacopoeia. Due to the potential toxicity of aristolochic acid I (AAI), a limited component in asarum, the possibility that its dosage also exceeds the dosage prescribed by the Chinese Pharmacopoeia had aroused wide concern. In this study, the UHPLC-Q TOF method was used to determine the presence of AAI in QFPD. A UHPLC-QQQ method was then established to determine the content of AAI in QFPD, a reflux extract of asarum and an ultrasonic extract of 70% methanol of asarum. The results showed that the amount of AAI in the three samples was approximate 1.5, 3.2 and 9.0 μg respectively with equivalent dosages of asarum (6 g). All were obviously lower than the maximum daily limit stipulated in the Chinese Pharmacopoeia (30 μg). Therefore, we concluded that the content of AAI could be effectively reduced by using a Chinese herbal compound decoction and optimization of asarum. This assay is not only convenient, rapid, sensitive and reproducible for the trace detection of AAI in Chinese herbal compound decoction, but also useful for the rational application of asarum in QFPD.
Pazufloxacin eardrops are a topical quinolone agent for the treatment of outer ear infection. The present study evaluated the pharmacokinetics and topical distribution of pazufloxacin eardrops by a sensitive LC-MS/MS method for determining pazufloxacin in plasma and otorrhea. Plasma and otorrhea samples were extracted by acetonitrile-induced protein precipitation and were subjected to liquid chromatography-tandem mass spectrometric analysis with an electrospray ionization interface. The samples were separated on an HSS T3 column (50 mm×2.1 mm, 1.8 μm). To avoid the matrix effect, gradient elution was performed with the mobile phase consisting of methanol and 1 mmol·L-1 ammonium acetate aqueous solution (0.1% formic acid). The ion transitions for pazufloxacin and pazufloxacin-d4 were m/z 319.1→281.2 and m/z 323.1→285.2, respectively, under the multiple reaction monitoring (MRM) mode. The method was linear in the range of 0.010 0-8.00 ng·mL-1 for pazufloxacin in plasma and 0.500-1 000 ng·mg-1 in otorrhea. The intra- and inter-day accuracy and precision for pazufloxacin in plasma and in otorrhea met acceptable criteria. The clinical trial was approved by the Society of Ethics and conducted in Nanjing First Hospital and Jiangsu Province Hospital. The validated methods were used in a systemic and topical pharmacokinetic study of 0.1% pazufloxacin eardrops in 3 patients with chronic suppurative otitis media.
The non-specific administration of antitumor drugs is the main cause for the side effects of chemotherapy drugs on normal tissues. The application of nanotechnology in the delivery of anti-tumor drugs is one of the important ways to improve the therapeutic effect and to reduce the side effects. The current study aimed to synthesize pH responsive poly (methoxy-ethylene glycol)-poly(lactic acid)-poly-(β-amino ester) (PBAE) triblock copolymers to deliver docetaxel (DTX) and improve the anti-tumor activity of DTX. PBAE was synthesized by ring opening polymerization and Michael addition reaction, its structure and molecular weight was characterized by 1H NMR, the dissociation constant of base (pKb) were determined by acid-base titration method. The critical micelles concentration (CMC) of copolymers was measured by pyrene fluorescence spectroscopy. DTX loaded copolymer micelles were prepared by membrane hydration method. The size and its distribution as well as the stability of micelles were determined by laser light scattering analysis. The drug loading content (DL), entrapment efficiency (EE) and cumulative drug release from micelles were evaluated by high-performance liquid chromatography (HPLC). The sizes of DTX drug-loaded micelles were in the range of 10 to 100 nm with narrow distribution. DL of DTX in PBAE1 and PBAE2 micelles was (5.3±0.10)% and (4.9±0.05)%, respectively, with EE was (93.8±1.70)% and (87.2±4.10)%, respectively. The drug-loaded micelles showed pH sensitive drug release properties under weak acidic conditions, which showed potential drug release of DTX under mild acidic tumor environment. A mouse Lewis lung carcinoma model was established to evaluate the therapeutic efficacy of micellar DTX formulations. Significant inhibitory effect of the nanodrugs was observed with DTX dosages of 10 and 20 mg·kg-1, respectively. Moreover, the pH responsive PBAE1-DTX micellar drug exhibited stronger therapeutic efficacy on mice xenograft tumor, as compared with the non pH sensitive micellar drug (PELA-DTX) and free DTX. All animal experiments were performed according to the animal ethical standards and approved by the Animal Experiments and Ethical Committee of China Academy of Chinese Medical Sciences (No. 2017090110). The in vivo anti-tumor activity studies showed that the tumor volume growth rates of mice in different drug-administered groups were:PBAE1-DTX 20 mg·kg-1 < PBAE1-DTX 10 mg·kg-1 < PELA-DTX 10 mg·kg-1 < DTX 10 mg·kg-1 < normal saline, with the PBAE1-DTX group as the most potent group for tumor inhibition. The current pH sensitive DTX nano-micelles showed high potential in further studies to promote the application of nano DTX formulations for tumor treatment.
In this study, physical fingerprint and multivariate statistical analysis was applied to characterize the quality consistency of different sources of carboxymethylcellulose sodium, and the visualization of R language was used to explore the intrinsic correlation on its performances, and we drew contour maps between independent variables and flowability of powder to find the design space. Through the physical fingerprint and multivariate statistical analysis, it was found that there were differences in the powder properties of carboxymethylcellulose sodium from different sources, and its moisture content, bulk density and tapped density have a great influence on the fluidity. The fillibility was positively correlated with flowability, both negatively correlated with compressibility by R intelligent visualization analysis, which was statistically significant (P < 0.01). When the angle of repose is 30°-40°, the appropriate design space was found as 5.092 2% < moisture content < 7.006 7%, 0.560 2 g·cm-3 < bulk density < 0.579 9 g·cm-3, and 0.646 3 g·cm-3 < tapped density < 0.816 5 g·cm-3. The results show that it is scientific and feasible to evaluate the quality consistency of pharmaceutical excipients by using the physical fingerprint, multivariate statistical analysis and visualization methods, which provides new ideas for the production and quality evaluation of excipients and the development of generic prescriptions.
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