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Objective To establish a method for the simultaneous determination of liquiritin, isoliquiritin, glycyrrhizin, isoliquiritigenin and glycyrrhizic acid in licorice extract. Methods Liquiritin, isoliquiritin, glycyrrhizin, isoliquiritigenin and glycyrrhizic acid in licorice extract were determined by HPLC dual wavelength spectrophotometry. Symmetry C18 column (4.6 mm × 250 mm, 5 μm) was used. The mobile phase was acetonitrile (A) - 0.085％ phosphoric acid water (B), ingradient elution mode (0–8 min, 81％ B; 8–35 min, 81％→50％ B; 35–60 min, 50％ B) with the flow rate of 1.0 mL/min. The sample size was 10 μL, and column temperature was room temperature. Dual wavelength detection, λ1=237 nm, λ2=254 nm. Results Liquiritin, isoliquiritin, glycyrrhizin, isoliquiritigenin and glycyrrhizic acid were linear in the ranges of 0.0408–0.816 μg, 0.0528–1.056 μg, 0.0224–0.448 μg, 0.0212–0.424 μg, and 0.0448–0.896 μg, respectively. The average recovery was 98.69％, 98.31％, 99.10％, 98.55％, and 99.14％, respectively; RSD was 1.39％, 1.29％, 1.78％, 2.14％, and 1.15 ％, respectively. Conclusion The method is accurate, reliable and specific. The results are stable with good repeatability. It can be used for the determine of above 5 components in licorice extract.
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OBJECTIVE:To determine the contents of chlortetracycline hydrochloride and tetracaine hydrochloride in compound chlortetracycline hydrochloride ointment.METHODS:Dual wavelength spectrophotometry was used to determine the two components.The absorbance of the two components was determined at wavelength of 311 nm,368 nm and 387.5 nm,respectively;and the contents of which were computed as well.RESULTS:The linear ranges for chlortetracycline hydrochloride and tetracaine hydrochloride were 9.90～29.71 ?g?mL-1 and 5.99～17.98 ?g?mL-1(r=0.999 9),respectively,with average recovery rates at 99.37%(RSD=0.31%,n=9) and 98.31%(RSD=0.23%,n=9),respectively.CONCLUSION:The method is simple,rapid and accurate,and suitable for the determination of compound chlortetracycline hydrochloride ointment.
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Objective To compare the effects of dual-wavelength spectrophotometry and HPLC on the content of trimethoprim(TMP)in Compound Dihydroartemisinin Tablets.Methods HPLC was performed in a column of C 18 with acetonitrile and 0.75% diethylamine(15∶85,adjusting pH to 2.5 by phosphoric acid)as the mobile phase and the detecting wavelength was at 271nm.The detecting wavelength was also at 271nm with reference wavelength at 366nm in dual-wavelength spectrophotomerty.Results Within 20.0～100.0 ?g/mL,TMP has a good linearity(r=0.999 94)by HPLC,and the average recovery was 100.9% with RSD being0.24%(n=5).By dual-wavelength spectrophotometry,a good linearity(r=0.999 95)of TMP was within 5.0～25.0 ?g/mL,and the average recovery was 100.0% with RSD being 0.45%(n=5).Conclusion Both dual-wavelength spectrophotometry and HPLC can be used to determine the content of TMP in Compound Dihydroartemisinin Tablets,but the former can detect the content of TMP directly without the disturbance of piperaquine phosphate and is simple,rapid and accurate.
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Objective: To determine strychnine content of Jinqianbaihuashe Medicinal Wine. Methods: The dual wavelength spectrophotometry was adopted. Results: The calibration curve was linear in the range of 1.6～ 14.4?g?mL -1 of strychnine. The average recovery rate was 99.35%. RSD was 0.74%(n=7). Conclusion: The method is reproducible, sensitive and prevent from the interference of other components.
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Objective: Hypericin content was determined in the extract of hypericum by dual-wavelength spectrophotometry. Methods: The wavelengths were adopeted 589nm～647nm against a methanol blank. Results: The linear correlation was observed within the range of 1.30～29.75?g/ml(r=0.9998). The average recovery of hypericin was 102.32%(n=6), RSD was 1.08%. Conclusion: the result was exact, method was simple and convenient .
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OBJECTIVE:The content of resorcinol in compound resorcinol lotion was determined by dual wavelength spec?trophotometry.METHODS:Absorbance was determined by using water as the solvent at the wavelength273.5nm and266.1nm.RESULTS:The results showed that the standard curve of resorcinol concentration ranging from20.32?g/ml to60.96?g/ml was in correspondence with Beer’s law.The absorbance difference and the concentration showed a good linear relationship(r=0.9998).The mean recovery of resorcinol was(99.59?0.45)%(n=9).CONCLUSION:This method is simple,quick and ac?curate.
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OBJECTIVE:Dual-wavelength spectrophotometry was developed for the determination of ciprofloxacin lactate in its eye drops.METHODS:Detection was performed at wavelength 237nm and 279nm with 0.1mol/L HCl as diluent.RESU_LTS:The assay was linear for ciprofloxacin lactate in the concentration range of 3～9?g/ml,r=0.9 998;The mean recovery was 101.6%,RSD was 2.16%.CONCLUSION:This method is simple,quick,accurate and suitable for the determination of ciprofloxacin lactate in its eye drops.