Antitumor mechanism of Qinghaosu derivatives--molecular docking studies of Qinghaosu derivatives with transferrin / 药学学报

To investigate the antitumor mechanism of artemisninin, a flexible docking analysis was used to score all kinds of functions of 11 Qinghaosu derivatives and transferrin with different resolutions. The distances of Asp-63, Tyr-188, His-249, Arg-124 and Lys-296 with Qinghaosu were less than 0.5 nm, separately. Meanwhile, the higher is the activity of Qinghaosu derivatives the higher is the score. Our model explains that Fe2+ is more feasible to react with Qinghaosu, and not involved in other metabolism in presence of transferrin. Docking results unveil that Iron(II)-transferrin increased the cytotoxicity of Qinghaosu derivatives and provide a rational basis for further design and synthesis of novel Qinghaosu derivatives.

Studies on characteristic fingerprints of fat-soluble components of Marsdenia tenacissima by GC / 中国中药杂志

<p><b>OBJECTIVE</b>To study characteristic fingerprints of the fat-soluble components of different Marsdenia tenacissima samples by GC and GC-MS.</p><p><b>METHOD</b>The sample was split in the 280 degrees C injection port, with 10:1 split ratio, and separated on a fused silica capillary column (DB-5, 30 m x 0.25 mm I. D., 0.25 microm film). The temperature program was 70 degrees C for 5 min, 8 degrees C x min(-1) to 200 degrees C, then 5 degrees C x min-1 to 260 degrees C, 260 degrees C for 10 min. The high pure nitrogen was used as a carrier gas, The FID temperature was 300 degrees C.</p><p><b>RESULT</b>There are 15 common peaks in the GC fingerprints of M. tenacissima and they are identified by GC-MS. The analyses on cluster and similarity degree of the finger the crude drugs from various habitats have been performed.</p><p><b>CONCLUSION</b>The method has good repeatability. The GC fingerprint combined with the HPLC fingerprint of M. tenacissim can be used to evaluate its quality integrally.</p>

Spectroscopic studies on the binding of sibutramine hydrochloride and bovine serum albumin / 药学学报

<p><b>AIM</b>To study the binding of sibutramine hydrochloride (SH) and bovine serum albumin (BSA) in physiological condition by spectroscopic method.</p><p><b>METHODS</b>The quenching mechanism of the fluorescence of bovine serum albumin by sibutramine hydrochloride was studied with the fluorescence and the absorption spectroscopy. The binding constants K and the number of binding sites were determined at different temperatures according to Scatchard equation and the main binding force was discussed by thermodynamic equations. The effect of the drug on bovine serum albumin conformation was also studied by using synchronous fluorescence spectroscopy.</p><p><b>RESULTS</b>The quenching mechanism of sibutramine hydrochloride to bovine serum albumin was static quenching. The binding constants K at 8 degrees C, 25 degrees C, 37 degrees C were 1.21 x 10(5), 8.31 x 10(4), 6.97 x 10(4) L x mol(-1) with one binding site, respectively. The thermodynamic parameters of the reaction were deltaH = -9.70 kJ x mol(-1), deltaS = 56.41 J x mol(-1) x K(-1).</p><p><b>CONCLUSION</b>The binding force is electrostatic interaction. Sibutramine hydrochloride can be deposited and transported by serum protein in vivo. Sibutramine hydrochloride has nearly no effect on the serum protein conformation.</p>

Determination of ursolic acid of Liuwei Dihuangwan simulation samples by NIR / 中国中药杂志

<p><b>OBJECTIVE</b>Determine the content of ursolic acid of Liuwei Dihuangwan.</p><p><b>METHOD</b>Using NIR with PLS, PCA-BPANN and WT-BPANN.</p><p><b>RESULT</b>The predication recovery were 100.7%, 100.6%, 100.1%, and the RSD were 5.42%, 6.49%, 6.52% respectively.</p><p><b>CONCLUSION</b>NIR can be used in the determination of ursolic acid, which set up the foundation of on-line control of traditional Chinese medicine.</p>

Rapid analysis of antiepileptic drugs in human plasma by micellar electrokinetic capillary chromatography / 药学学报

<p><b>AIM</b>To develop a rapid and feasible method based on micellar electrokinetic capillary chromatography (MECC) for the simultaneous determination of antiepileptic drugs (AEDs)--phenytoin (PHT), phenobarbital (PB), carbamazepine (CBZ), primidone (PRM) and clonazepam (CZP) in human plasma.</p><p><b>METHODS</b>Several factors that impact the separation of AEDs with MECC were investigated, such as concentration of sodium dodecyl sulfate (SDS), buffer compositions, pH, organic modifier, internal diameter and temperature, and an optimized MECC running condition was obtained the running buffer consisted of 8 mmol x L(-1) phosphate, 3 mmol x L(-1) sodium tetraborate, and 50 mmol x L(-1) sodium dodecylsulfate (SDS) (pH 8.0), containing acetonitrile (ACN) (18%) as organic modifier. Detection at 210 nm, run at 25 kV at 30 degrees C in a untreated fused silica capillary (50/45.5 cm length, 50 microm ID).</p><p><b>RESULTS</b>The reproducibility of both migration time and relative peak area with MECC analysis were appropriate for the intra- and inter-assay coefficients. The evaluated drugs concentration intervals of PRM 1.0-40.0 microg x mL(-1), PB 1.0-60.0 microg x mL(-1), PHT 1.0-40.0 microg x mL(-1), CBZ 1.0-40.0 microg x mL(-1), CZP 0.2-8.0 microg x mL(-1) were linear with correlation coefficients higher than 0.999 1, and coefficients of the variation of the points of the calibration curve lower than 10%. The recoveries of AEDs varied from 80.0% to 100.0%, depending on the drug, with coefficients of the variation lower than 10.0%.</p><p><b>CONCLUSION</b>The MECC technique is showed to be rapid, simple, efficient and low cost when applied to monitoring therapeutic drugs in patient treated with a combination of PHT and other AEDs such as hepatic enzyme-inducing agents.</p>

A quantum chemistry investigation on antimalarial mechanism of Qinghaosu based on cleavage of the peroxide bridge / 药学学报

<p><b>AIM</b>To investigate antimalarial mechanism of Qinghaosu ( QHS) and its derivatives.</p><p><b>METHODS</b>The electronic structure of QHS and its derivatives were completely optimized and calculated at B3LYP/6-31G * level, while the route was at HF/STO-3G level.</p><p><b>RESULTS</b>The peroxide bridge is the active center of QHS and induced by ferrous iron to produce cyclic product.</p><p><b>CONCLUSION</b>Heme can link with QHS derivatives.</p>

Application of stochastic resonance to quantitative analysis of weak chromatographic signal of phenazopyridine in human plasma / 药学学报

<p><b>AIM</b>To apply stochastic resonance algorithm (SRA) to quantitative analysis of weak chromatographic signal, which was embedded in the noise.</p><p><b>METHODS</b>Based on the theory of stochastic resonance (SR), a simple and effective SRA has been established to improve analytical detection limits of chromatographic analysis, which apply to enhance the signal to noise ratio by the optimization of the parameters and Runge-Kutta method, was established. The method was used to quantitative analysis of phenazopyridine in human plasma by HPLC/UV. Meanwhile this method is compared with HPLC/MS.</p><p><b>RESULTS</b>By experimental chromatographic data sets, an excellent quantitative relationship between concentrations of phenazopyridine and their responses had been obtained. The concentration of phenazopyridine in plasma determined by HPLC/UV with SRA and HPLC/MS showed that there was no significant difference (P > 0.05) between the two methods.</p><p><b>CONCLUSION</b>The new method was feasible.</p>

A near-infrared diffuse reflectance analysis method for the noninvasive quantitative analysis of ambroxol hydrochloride tablets / 药学学报

<p><b>AIM</b>To develop a near-infrared diffuse reflectance analysis (NIRDRA) method for rapid noninvasive quantitative determination of ambroxol hydrochloride in half-finished product particles and non-blister-packed, blistered tablets.</p><p><b>METHODS</b>All spectra were measured with a Fourier transform spectrometer equipped with a PbS and a InGaAs detector, an external integrating sphere, a rotating sample cup, and a fibre-optic probe for reflectance measurements. All samples were scanned from 12,000 cm-1 to 4,000 cm-1, and each sample spectrum was obtained as an automatic mean of 64 scans. No spectrum pre-processing method was used, and spectral regions, 4,602-4,247, 12,000-7,498 and 6,102-5,446, 12,000-5,446 cm-1 were selected to develope mathematical models by partial least square method for half-finished product particles and non-blister-packed, blistered tablets samples, respectively.</p><p><b>RESULTS</b>The optimal rank and mean square error determined for half-finished product particles and non-blister-packed, blistered tablets samples by cross validation method all was 6 and 0.306, 0.972 and 1.492, respectively, the average recovery was 100%, 100% and 102% respectively; and the RSD was 1.17%, 1.70% and 1.78% respectively.</p><p><b>CONCLUSION</b>Results showed that the NIRDRA method was rapid, simple, noninvasive and sensitive, and it can be applied to assay the content of ambroxol hydrochloride in half-finished product particles non-blister-packed and blistered tablets.</p>

Determination of loratadine in human plasma by HPLC with fluorescence detector and study on its bioavailability / 药学学报

<p><b>AIM</b>To establish an HPLC-fluorescence method for determination of loratadine in human plasma and evaluate its relative bioavailability.</p><p><b>METHODS</b>An Alltech-C18 column and a mobile phase of acetonitrile-water-glacial acetic acid-triethylamine (90:100:6:0.15) were used. The fluorescence detector was set at Ex 274 nm, Em 450 nm. The flow rate was 1 mL.min-1.</p><p><b>RESULTS</b>The calibration curve was linear over a concentration range of 0.2-30 micrograms.L-1. The limit of quantification was 0.2 microgram.L-1. The average method recoveries varied from 96% to 98%. The results showed AUC, Tmax, Cmax and T1/2 beta between the testing tablets, testing capsules and reference tablets had no significant difference (P > 0.05). Relative bioavailabilities were 107% +/- 17% and 100% +/- 14% respectively.</p><p><b>CONCLUSION</b>The three formulations were bioequivalent.</p>

Determination of first-order structure of somatostatin by electrospray ionization mass spectrometry / 药学学报

<p><b>AIM</b>To determine the molecular weight and first-order structure of somatostatin.</p><p><b>METHODS</b>The molecular weight of somatostatin was determined by electrospray ionization mass spectrometry. Somatostatin was deoxidized by 2-mercaptoethanol. A series of typical fragment ions of deoxidized product were obtained by insource collision-induced dissociation (CID).</p><p><b>RESULTS</b>The m/z of quasi-molecular ion [M + H]+ of somatostatin was 1,637.8 and [M + Na]+ was 1,659.5. The m/z of double-charge ion [M + 2H]2+ was 819.5 and [M + H + Na]2+ was 830.3. It showed that the molecular weight of somatostatin was 1,636.7. The y and b series of fragment ions of deoxidized product were obtained by adjusting the fragmentor voltage. It was determined that the first-order structure of deoxidized product of somatostatin was A-G-C-K-N-F-F-W-K-T-F-T-S-C.</p><p><b>CONCLUSION</b>The molecular weight and first-order structure of somatostatin were confirmed.</p>