ABSTRACT
Objective To development a cooling crystallization process that is suitable for industrial preparation of purified dihydromyricetin.Methods Screen design was used to investigate effects of process parameters such as,temperature,concentration ethanol aqueous,quantity of activated charcoal and adsorption time on yield and purity of dihydromyricetin.Purity was verified by high performance liquid chromatography and thin layer chromatography.The solubility of dihydromyricetin in water at viable temperature and ethanol proportion was also determined by UV spectrophotometry.The solid form was characterized by thermal analysis and powder X-ray diffractometry.Results When temperature was ＞ 85 ℃,ethanol concentration ＜ 10％,dosage of activated charcoal 0.1％-0.3％,and adsorption time 1-3 min,yield of dihydromyricetin was more than 70％,and the purity greater than 98％.The crystals,prepared by cooling crystallization from water and ethanol aqueous,had the same physical form and crystal habit.Conclusion Cooling crystallization from low concentration of ethanol aqueous gets higher yield and the process is more robust than crystallization from water.
ABSTRACT
Objective To establish a HPLC method for the determination of related substances in lysine hydrochloride and zinc gluconate oral solution. Methods The HPLC separation was performed at 30 ℃ on an Inertsil Amide column (4.6 mm×250 mm,5 μm) by gradient elution with mobile phase A [phosphatesolution (2.72 g KH2PO4and 0.46 goctane sulfonate,added with 1 000 mL)-acetonitrile (22:78)] and B [phosphate solution-acetonitrile (95:5)] at the flow rate of 1.0 mL·min-1.The clumn temperature was 30 ℃.The determination wavelength was 203 nm. Results The major peaks were well separated from adjacent related substances peaks and resolution were greater than 2.0.The theoretical plate number of major peaks and related substance peaks were greater than 3 000.Excipients and destruction test products did not interfere with the determination. Conclusion This method is practicable,specific and durable for the simultaneous determination of related substances in lysine hydrochloride and zinc gluconate oral solution.