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Biomedical subjects

D K An

Publications and source records attributed to D K An.

36 records · Page 2Linked to original sources
PubMed1990

[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.

Chromatography, Gas↗
PubMed1990

[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).

Chlordiazepoxide↗
PubMed1989

[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.

Niacinamide↗
PubMed1989

[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.

Chromatography, Gas↗
PubMed1989

[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).

Drug Combinations↗
PubMed1989

[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%.

Berberine↗
PubMed1989

[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%.

Berberine↗