Objective: To study the related substances in clozapine and its preparations. Methods:Comparative analysis was adopted according to the method respectively described in Chinese pharmacopoeia and United States pharmacopoeia. Results:The impurity profile of clozapine from domestic and abroad was basically the same, and that of clozapine and its preparations was also basically the same. The method in United States pharmacopoeia was better than that in Chinese pharmacopoeia in terms of in terms of separation of the impurities. Conclusion: The current legal inspection standard for the related substances in clozapine described in Chinese pharmacopoeia should be improved.

Objective: To establish a content determination method for ferric iron and ferrous iron in ferrous succinate tablets.Methods: Using a Dionex RFICTM protection column (4 mm×50 mm)and a Dionex RFICM Ion PacRCS5A analytical column (4 mm×250 mm), the eluent solution consisted of 7 mmol·L-1 dipicolinic acid, 66 mmol·L-1 potassium hydroxide, 5.6 mmol·L-1 potassium phosphate monobasic and 74 mmol·L-1 formic acid.The flow rate was 1.5 ml·min-1, the column temperature was 30.0℃ and the injection volume was 1.3 μl.Results: Fe3+ showed good linearity within the range of 0.5-15 μg·ml-1(r=1.000 0), Fe2+ showed good linearity within the range of 25-200 μg·ml-1(r=1.000 0), and the average recovery was 103.6%(RSD=2.7%, n=9)and 98.3%(RSD=1.9%, n=9), respectively.Conclusion: The method is simple, reliable and accurate, and can be used for the determination of Fe3+and Fe2+ in ferrous succinate tablets.

OBJECTIVETo established a novel HPLC-PAD method for the simultaneous determination of five compounds (camellianin A, camellianin B, apigenin, quercitrin, epicatechin) in leaves of Adinandra nitida.

METHODThese compounds were effectively separated on a reversed-phase C18 column (4.6 mm x 250 mm, 10 microm) with the column temperature at 25 degrees C. The mobile phase was composed of 0.1% aqueous formic acid and methanol. The flow rate was 1.0 mL x min(-1), the detection wavelength was set at 280 nm before 15 min for detecting epicatechin and at 262 nm from 15 to 40 min for detecting the rest four compounds.

RESULTAll the linearities were good (r > 0.9991) within their test ranges. The established method showed good precision with overall intra-day and interday RSD values less than 3.33% and 3.2%, respectively. The average recoveries were in the range of 96.08% to 100.30% with RSD from 2.0% to 4.0%. The limits of detection (LOD) and quantification (LOQ) in the range of ranged from 0.9 to 5.6 ng and 3.0 to 19.0 ng, respectively.

CONCLUSIONThis established method can be applied to evaluate the intrinsic quality of the leaves of A. nitida.

Chromatography, High Pressure Liquid ; instrumentation ; methods ; Drugs, Chinese Herbal ; analysis ; Flavonoids ; analysis ; Magnoliopsida ; chemistry ; Plant Leaves ; chemistry