A concise synthesis of turneforcidine via a metalloiminium ion cyclization terminated by the 2-(methylthio)-3-(trimethylsilyl)-1-propenyl moiety.

A concise synthetic route to racemic turneforcidine (1) is described that relies on the stereocontrolled cyclization of the 2-(methylthio)-3-(trimethylsilyl)-1-propenyl bearing imine 5 in the presence of TiCl(4). Reaction: see text.

[Simultaneous determination of four components in vitamin B compound tablets by Kalman filtering spectrophotometry].

The four principal components, vitamin B1, B2, B6 and nicotinamide in vitamin B compound tablet show certain instabilities individually and the amounts of these components differ considerably in the tablets, so their simultaneous determination without prior separation is usually difficult. This paper deals with the feasibility of using Kalman filtering spectrophotometry to do so, and makes some efforts concerning the deviation from the Beer-Lambert law due to mutual effects among the acting molecules. The results obtained were comparatively satisfactory both in precision and in accuracy. The average recovery of vitamin B1, B2, B6, and nicotinamide were 100.2 +/- 0.90% (CV), 100.3 +/- 1.7% (CV), 101.1 +/- 3.3% (CV), 99.90 +/- 0.65% (CV) respectively and were better than those in previous reports. All these show that the use of Kalman filtering spectrophotometry to the assay of vitamin B compound tablets is feasible.

[Studies on the chemical constituents of Tripterygium hypoglaucum (Lévl) Hutch].

A new diterpene, named Triptonoditerpenic acid. C21H28O4, mp 189-190 degrees C, has been isolated from Tripterygium hypoglaucum (Levl) Hutch. Its structure was elucidated by UV, IR, MS, 1HNMR, 13CNMR and 2D-NMR spectroscopic analyses.

[Simultaneous determination of 6 components contained in compound reserpine tablets by Kalman filtering spectrophotometry].

Kalman filtering spectrophotometry was investigated to assay the contents of vitamin B1, vitamin B6, chlordiazepoxide, dihydralazine sulfate, promethazine hydrochloride and hydrochlorothiazide in compound reserpine tablets consisting of 10 components. Absorption proportionality constant for each component was obtained by the application of non-negative least square method. The average recoveries for each were 97-103% with CV% less than or equal to 6.9 except vitamin B1 (n = 11).

[Determination of compound preparation containing unknown absorptive background by UV spectrophotometry].

A novel algorithm of target factor analysis has been developed for detection and correction of unknown absorptive background in multicomponent analysis. The algorithm is based on the property that the estimated spectra can gradually approach the true ones by iterative refinements. Paracetamol and antipyrine contained in compound injection of paracetamol were determined by this method without any preliminary chemical separation. The average recoveries were both 100.0% and the coefficients of variation were 1.1% and 1.0% respectively. The results clearly indicate that the proposed method may also provide a new approach to the analysis of traditional Chinese medicine containing some unknown absorptive components.

[Classification of Chinese traditional medicine, moutan (Paeonia suffruticosa Andr.) cortex by means of pyrolysis-high resolution gas chromatography/pattern recognition].

Thirty-eight samples of Moutan (Paeonia suffruticosa Andr.) Cortex obtained from three different regions (Southwest, East and Middle China) and two samples of unknown region were subjected to analysis with pyrolysis-high resolution gas chromatography (Py-HRGC). Each sample was thus characterized by the peak area of 41 peaks in each Py-HRGC profile. Discriminant analysis (DA), PRIMA and SIMCA pattern recognition were used to recognize the 40 x 41 data matrix. These data analysis gave satisfactory results (DA, 100% correct; PRIMA, 100% correct, 92.2% unique; SIMCA, 92.2% correct, 79% unique). The correct classification of Moutan Cortex for the unknown territory was obtained by three pattern recognition methods. The results showed that Py-HRGC/pattern recognition technique might be a potential tool for the identification of Chinese traditional medicine.

[Study on the determination of zinc in plasma after oral administration of licorzin by atomic absorption spectrophotometry and the pharmacokinetics of zinc in healthy volunteers].

A rapid, accurate and sensitive atomic absorption spectrophotometry was established for the determination of zinc in plasma after oral administration of licorzin to healthy volunteers. The plasma sample diluted with de-ionized water (1:1) was determined directly. A 5% glycerol solution was used as the solvent of zinc standard solution. The recovery of the proposed method was 97.3 +/- 4.3%. The precisions (CV%) of within-day and day-to-day were less than 5%. The pharmacokinetics of zinc in healthy volunteers after oral administration of 2.5 g licorzin was studied. The results showed that an one-compartment model (Ka = K) was found in 10 healthy volunteers. The pharmacokinetic parameters were as follows: Ka = K = 0.380h-1, Tmax = 2.7h, V = 33.03 L, T1/2 = 1.9h.

[P-matrix spectrophotometric determination of 6 components contained in compound reserpine tablets].

P-matrix method has been developed for the simultaneous determination of vitamin B1, vitamin B6, chlordiazepoxide, dihydralazins sulfate, promethazine hydrochloride and hydrochlorothiazide contained in compound reserpine tablets consisting of 10 components. The optimal wave-length for measurement was successfully selected based on the principle of condition number. The influence of experimental error, number of wavelength and condition number deviation of component concentration from formula were discussed. The average recoveries varied from 97-103% with CV less than or equal to 9.5% (n = 11).

[High performance liquid chromatography/electrospray ionization mass spectrometric characterization of recombinant L-asparaginase II].

AIM: To characterize the primary structure of recombinant L-asparaginase II product. METHODS: The molecular weight of the protein was measured by pneumatically-assisted electrospray ionization mass spectrometry with flow injection mode. Subsequently, tryptic peptide mapping was performed by high performance liquid chromatography on a C8 column with tandem UV and MS detection. An easy-to-use and simple denaturation process with trichloroacetic acid was conducted prior to tryptic digest so as to release the digest resistance from the protein structure. The amino acid sequences of the tryptic peptides were elucidated based on their in-source collision-induced dissociation spectra. RESULTS: The measured molecular mass was different from the theoretical value. Three amino acid variations were unambiguously detected along the peptide backbone derived from the gene-encoding sequence. CONCLUSION: This paper revealed that LC/ESI/MS had provided a promising and robust technique in primary structure analysis and quality control of DNA-derived recombinant protein pharmaceuticals.

[Study on the phase I metabolites of phenoprolamine hydrochloride in rat bile by LC/DAD/MSD].

AIM: To study the phase I metabolites of phenoprolamine hydrochloride (DDPH) in rat bile. METHODS: DDPH was administered i.p. to bile duct-cannulated rats. Bile samples were collected before administration and up to 12 h after administration. After being treated with beta-glucuronidase, the bile samples were purified and enriched with C-18 SPE columns, and then were analyzed by LC/DAD/MSD. The samples containing synthesized reference standards of DDPH metabolite 1-(2, 6-dimethylphenoxy)-2-(3-methoxy-4-hydroxyphenylethylamino)-propane (M1), 1-(2, 6-dimethyl-3-hydroxyphenoxy)-2-(3, 4-methoxy-phenylethylamino)-propane (M2), 1-(2,6-dimethyl-4-hydroxyphenoxy)-2-(3,4- methoxyphenylethylamino)-propane (M3), 1-(2, 6-dimethyl-3-hydroxyphenoxy)-2-(3-hydroxy-4- methoxyphenylethylamino)-propane (M4), 1-(2, 6-dimethyl-3-hydroxyphenoxy)-2- (3-hydroxy-4-methoxyphenylethylamino)-propane (M5) and 1-(2,6-dimethyl-4-hydroxyphenoxy)-2-(3-methoxy-4- hydroxyphenylethylamino)-propane (M6) were analyzed by LC/DAD/MSD under identical conditions. RESULTS: The retention times, UV spectra, molecular weights and production spectra (obtained by collision-induced dissociation) of the apparent ions of peak A, B, C, D, E and F in the total ion chromatogram of DDPH treated rat bile sample were consistent with those of M1, M2, M3, M5, M4 and M6, respectively. CONCLUSION: M1, M2, M3, M4, M5 and M6 were identified as the phase I metabolites of DDPH in the rat.

[Study on the phase II metabolites of phenoprolamine hydrochloride in rat bile by LC/DAD/MSD].

AIM: To study the phase II metabolites of phenoprolamine hydrochloride (DDPH) in rat bile. METHODS: DDPH was administered by i.p. to bile duct-cannulated rats. Bile samples were collected before drug administration and up to 12 h after drug administration. After being purified and enriched with C-18 SPE columns the rat bile samples were analyzed by LC/DAD/MSD to identify the peaks of phase II metabolites. The fractions of phase II metabolites were prepared by HPLC and treated with beta-glucuronidase, and then were purified and enriched with C-18 SPE columns and analyzed by LC/DAD/MSD. The corresponding reference standards of DDPH phase I metabolites were analyzed by LC/DAD/MSD under identical conditions. RESULTS: The peaks M7, M8 and M9 in the chromatograms of rat bile samples were the phase II metabolites of DDPH and the enzymatic hydrolysates of M7, M8 and M9 were 1-(2, 6-dimethyl-4-hydroxyphenoxy)-2-(3, 4-methoxyphenylethylamino)-propane (M3), 1-(2, 6-dimethyl-3-hydroxyphenoxy)-2-(3, 4-methoxyphenylethylamino)-propane (M2) and 1-(2,6-dimethylphenoxy)-2-(3-methoxy-4-hydroxyphenylethyl-amino)-propane (M1) respectively. CONCLUSION: beta-1-O-[3,5-dimethyl-4-[-2-methyl-2-(3,4-dimethoxy-phenylethylamino)- ethoxy]-phenyl]-glucuronic acid (M7, glucuronide of M3), beta-1-O-[2, 4-dimethyl-3-[2-methyl-2-(3, 4-dimethoxy-phenylethylamino)-ethoxy]-phenyl]-glucuronic acid (M8, glucuronide of M2) and beta-1-O-[2-methoxy-4-[1-methyl-2-(2, 6-dimethylphenoxy)-ethylamino-ethyl]-phenyl]-glucuronic acid (M9, glucuronide of M1) were the phase II metabolites of DDPH in rat bile.

[HPLC/ESI MS and MALDI/TOF MS analysis of microheterogeneity of the N-linked oligosaccharides of recombinant human erythropoietin].

AIM: To elucidate the microheterogeneity of three N-linked oligosaccharide sites of the Chinese-made recombinant human erythropoietin (rHuEPO). METHODS: Glu-C digestion, RP-HPLC separation, online HPLC/electrospray ionization mass spectrometry and matrix-assisted laser desorption/ionization time of flight mass spectrometry. RESULTS: The sialic acid was analyzed directly. Almost every oligosaccharide was acetylated, the acetylation of tetraantennary + 2LacNAc + 4SA and tetraantennary + 2LacNAc + 4SA were reported. CONCLUSION: The acetylation of multi-antennary oligosaccharide will improve the activity of rHuEPO in vivo. The biantennary oligosaccharide was found mainly existing at N-24. For the first time, the carbohydrate structures of each N-linked glycosylated site of Chinese-made rHuEPO were reported.

[Pharmacokinetics and disposition of triptonide in rats].

Triptonide, isolated from Tripterygium wilfordii Hook., was found to show significant antiinflammatory, immunosuppression and antitumor activities. A RP-HPLC method was applied to determine the plasma concentration of triptonide at different times in rats. Concentration-time curves after i.v., 0.7, 1.4 and 2.8 mg.kg-1 of triptonide were fitted to a two-compartment open model with T1/2 alpha of 0.167-0.195 h and T1/2 beta of 4.95-6.49 h. The area under curves (AUCs) were linearly related to the dosages (gamma = 0.9894). Systematic clearances (CLs) were independent of dosages. Mean residence time (MRT) of the three doses was 3.26-5.14 h by noncompartmental (the statistical moment method) analyses. The tissue distribution of triptonide in rats appeared to be wide throughout the body. The triptonide levels were high in the lung and liver, moderate in the heart, kidney, spleen and muscle and low in the testis, intestine and brain. Data of the urine and bile excretion indicated that only a small percent of unchanged triptonide was excreted. Plasma protein binding of triptonide rate was about 75%.

[Determination of berberine in Angong Niuhuang Wan by HPLC].

A normal phase liquid chromatographic method was developed for the determination of berberine-type alkaloids in rhizoma Coptidis and traditional Chinese medicine--Angong Niuhuang Wan. Experimental evidences indicate that a normal phase system of a silica column (3.9 x 250 mm) as stationary phase with an eluent of ethyl acetate-formic acid-ethanol (15:3:2) as mobile phase can separate excellently (R5 greater than 1.5) four berberine-type alkaloids in the samples tested. According to the results obtained with this method the percent content of berberine hydrochloride in some Angong Niuhuang Wan from different factories and different batches was 0.331-0.456% and the average recovery was 97.23%; coefficient of variation was 1.2%.

[Determination of berberine and palmatine in cortex phellodendron and Chinese patent medicines by HPLC].

Berberine (1) and palmatine (2) in cortex phellodendron and Chinese patent medicines were determined by HPLC. The optimal composition of mobile phase CH3COOEt-HCOOH-EtOH (15:3:2) for HPLC separation of berberine and palmatine was successfully determined by using window diagram technique. Detection wavelength was 346nm. Flow rate: 1.5 ml/min. Calibration graphs for 1 and 2 were rectilinear for 0.06-0.32 micrograms and 0.12-0.32 micrograms respectively. The average recoveries of the two corresponding components were found to be over 96% and their coefficients of variation were below 5%.

[Retention index of essential oil in temperature-programmed capillary column gas chromatography].

Kovats retention indexes of more than 200 kinds of natural and synthetic compounds of alcohol, aldehyde, acetal, ketone, ether, alkene, nitrile, carboxylic acid, ester, etc. were determined on polar liquid phase (DB-WAX) and nonpolar liquid phase (DB-1) by linear temperature-program capillary column gas chromatography. Some rules of part of the homologous series of compounds were summed up from the retention indexes: the rules of RI vs carbon, RI vs boiling point and RI on two columns. In order to keep the retention indexes practical, effects of initial temperature (T0), program rate (r) and average linear carrier gas velocity (u), etc. on the retention indexes were investigated. The conclusion is that the retention indexes are highly reproducible so long as the program parameters change in a certain range. Two kinds of essences, Meigui and Linglan, were identified successfully on IBM-PC/XT microcomputer by the Data Base Management System of essential oil and essence by capillary column gas chromatography and the results are satisfactory.

[Quantitative analysis of compound injection of aminopyrine by dual-wavelength linear regression spectrophotometry].

A dual-wavelength linear regression spectrophotometry has been introduced and evaluated. Depending on a group of standard mixture solutions the optimal wavelengths and calibration curve can be determined simultaneously by linear regression method. The deviation of absorption resulting from molecular interaction can be calibrated by this method and the results are more accurate. The validity of this method has been confirmed through its use in the analysis of compound injection of antipyrine with satisfactory recoveries. Results obtained by Kalman filtering (KF), partial least squares (PLS) and target factor analysis (TFA) are also given.

[Effect of solution pH value on the chelation structure of zinc acexamate by electrospray ionization mass spectrometry].

AIM: To study the effect of solution pH value on the chelation structure of zinc acexamate. METHODS: A series of samples at different solution pH values were prepared by 10% HCl or 1 mol.L-1 NH3.H2O. Then API/TOFMS with electrospray ion source was applied to assay the samples. The nitrogen curtain gas and nebulizer gas were adjusted to a constant flow rate of 0.6 microL.min-1 and 2 microL.min-1 respectively. Samples were infused into the electrospray interface using a 500 microL syringe pump at a flow rate of 5 microL.min-1. Mass spectra were acquired in positive ion modes by scanning over the range of m/z 100-1,000. RESULTS: The chelation structure of zinc acexamate is stable at pH 2.54 and it can be easy to form the ion (M + ZnY)+ (Y = CH3CONH(CH2)5COO-) and (2M + Na)+ in this condition. CONCLUSION: The drug is an effective antiulcer agent. It may decrease the acidity of stomach juice, and form a polymer to protect the ulcer.

[Study on the chemical constituents of Tripterygium hypoglaucum (Lévl.) Hutch].

Two new diterpenes, named triptoditerpenic acid B(2) and hypodiolide A(3), respectively, were isolated from Tripterygium hypoglaucum (Lévl.) Hutch. Their structures were elucidated on the basis of spectra and X-ray analysis.

[Analysis of the metabolite of 7-(4-chlorbenzyl)-7,8,13,13a-tetrahydroberberine in rabbit].

AIM: To explore the biotransformation of compound 7-(4-chlorbenzyl)-7,8,13, 13a-tetrahydroberberine in the rabbit. METHODS: Analyze the rabbit bile sample with HPLC, LC/MS and LC/NMR. RESULTS: A metabolite and unchanged 7-(4-chlorbenzyl)-7,8,13,13a-tetrahydroberberine were found in the rabit bile, the metabolite was characterized and its structure was elucidated. CONCLUSION: Compound 7-(4-chlorbenzyl)-7,8,13,13a-tetrahydroberberine is metabolized by demethylation at 10-OCH3 position.