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Supercritical fluid chromatography, using carbon dioxide as the mobile phase and ethanol as a modifier, has been applied to the analysis of products formed in rat liver microsomal metabolism of racemic camazepam, a hypnotic/anxiolytic drug in clinical use. An achiral (amino) column and a chiral (Chiralcel OD-H) column were used. The results suggest that achiral and chiral packed-column supercritical fluid chromatography gives a shorter analysis time and higher selectivity and efficiency than achiral and chiral stationary-phase high-performance liquid chromatography in the analysis of camazepam and its derivatives.

To establish a HPLC method for determination two constituents in bark of Paeonia Suffuticosa.The reversed phase HPLC system consisting of an Alltima ODS column (4.6 mm x 150 mm, 5 microm) and a mixture of water-THF-methanol-HAc (60:20:20:0.05) as the mobile phase was used. The flow rate was 0.8 mL x min(-1) and UV detection was set at 274 nm.The assay displayed good linearity over the concentration ranges of 0.06-1.0 microg (r = 0.999 9, gallic acid) and 0.16-2.58 microg (r = 0.999 9, paeonol) respectively. The average recoveries (n = 9) of gallic acid and paeonol were 98.6% (RSD = 3.0%), 98.2% (RSD = 2.5%), respectively. The samples were extracted with methanol for 24 h bu maceration.The method is simple, accurate and can be used for the quality study of bark of P. suffruticosa.

Several high performance liquid chromatographic methods for the analysis of gossypol in different kinds of sample were developed. (1) Pure gossypol: separation on C18 column with MeOH/H2O/CHCl3 (70:30:40) containing 0.1% H3PO4 as mobile phase or on SO3H column with MeOH/citrate buffer (pH 6.3) (55:45) as mobile phase was recommended. With these systems, minute amounts of contaminants difficult to separate by other HPLC systems could be determined. (2) Plant material: acetone was selected as the extraction solvent. After evaporation of acetone from the extract, the residue was redissolved in 1% HOAc in CHCl3. An aliquot of this solution was chromatographed and quantified by peak area method. The mean recovery of pure gossypol added to plant material was 91.1 +/- 1.1% (S.D.). (3) Plasma sample: a HPLC method with electrochemical detector was developed. A plasma sample with glutathione as protective agent and gossypol dimethyl ether as internal standard was introduced on to a C18 pre-column. By using column-switching technique, a certain part of the eluate containing gossypol and gossypol dimethyl ether was subjected to a C8 analytical column for further separation. MeOH/citrate buffer (pH 3.2) (80:20) was used as the mobile phase. The optimum potential for detection was +0.6 V vs. Ag-AgCl. The assay sensitivity was 5 ng/ml. This method is sensitive and selective, suitable for clinical pharmacokinetic studies.

A sensitive and selective high-performance liquid chromatographic method with electrochemical detection for the determination of gossypol in human plasma is described. Glutathione is used as a protective agent and gossypol dimethyl ether as an internal standard. Acetonitrile-treated protein-free plasma sample is first introduced on to a C18 pre-column for enrichment and clean-up. By using a column-switching technique, gossypol and the internal standard are subjected to further separation on a C8 analytical column, while the major interfering components are eliminated before entering the column. Methanol-0.1 M citrate buffer (pH 3.2) (80:20) is used as the mobile phase. The detector potential on the glassy carbon electrode is maintained at +0.6 V vs. an Ag-AgCl reference electrode. The linearity with human plasma ranged from 5 to 250 ng/ml. The absolute recoveries of gossypol and gossypol dimethyl ether were 91.3 and 97.5%, respectively, with a within-day precision of 2.5% and a day-to-day precision of 3.8%. The limit of detection is 5 ng/ml (signal-to-noise ratio = 3:1). The method is considered to be suitable for the clinical pharmacokinetic studies of gossypol.

Pharmacokinetic parameters of (+ or -)- (+)- and (-)-gossypol were determined in humans and dogs after a single oral or intravenous dose. Mean (+or- SD) oral bioavailability of (+or-)- gossypol in dogs was 30.9% +or- 16.2%. Studies in dogs who received single intravenous injections revealed that the elimination t 1/2 and volume of distribution of (=)-gossypol were 5 and 6 times those of (-)-gossypol respectively whereas total body clearance and the AUC of the 2 anantiomers were similar. Data from men receiving the compounds orally show that the average peak plasma concentration and the AUC of (+)- gossypol are significantly greater than those of the (-)-isomer. The rate constants of alpha beta ka k21 and k10 for (-)-gossypol are significantly greater than those for (+)-gossypol indicating higher rates of mass transfer of the (-)-species. In humans the elimination of t 1/2 of (+)-gossypol was 29 times as that of (-)-gossypol a difference that is more striking than that found in dogs. The elimination of t 1/2 of (+or-)-gossypol in humans averages 286 +or- 179 hours. (authors)