title: Validated HPLC method for determination of sennosides A and B in senna tablets.
abstract: This study developed an efficient and reliable ion-pair liquid chromatographic method for quantitation of sennosides A and B in commercial senna tablets. Separation was conducted on a Hypersil C 18 column (250 x 4.6 mm, 5 microm) at a temperature of 40 degrees C, using a mixture of 0.1 M acetate buffer (pH 6.0) and acetonitrile (70:30, v/v) containing 5 mM tetrahexylammonium bromide as mobile phase. Sennosides A and B were completely separated from other constituents within 14 min. The developed method was validated. Both run-to-run repeatability (n=10) and day-to-day reproducibility (n=3) of peak area were below 0.4% RSD. Linearity of peak area was tested in the range 30-70 microg/ml (r>0.9997). Accuracy was assessed with recovery and the recoveries for sennosides A and B were 101.73+/-1.30% and 101.81+/-2.18% (n=3 x 6), respectively. Robustness of the analytical method was tested using a three-leveled Plackett-Burman design in which 11 factors were assessed with 23 experiments. Eight factors (column, concentration of ion pair reagent, % of organic modifier (acetonitrile), buffer pH, column temperature, flow rate, time constant and detection wavelength) were investigated in a specified range above and below the nominal method conditions. It was found that: (1) column and % acetonitrile affected significantly resolution and retention time, (2) column, % acetonitrile, column temperature, flow rate and time constant affected significantly the plate number of sennoside A, and (3) column and time constant affected significantly the tailing factor.
authors.affiliation: School of Pharmacy, National Taiwan University, 1 Jen-Ai Road Sec. 1, Taipei, Taiwan, ROC. shaowen@ha.mc.ntu.edu.tw
authors.forename: Shao Wen
authors.initials: SW
authors.lastname: Sun
authors.forename: Hsiu Ting
authors.initials: HT
authors.lastname: Su
mesh_terms: D000880:Anthraquinones / Q000032:analysis*; D002021:Buffers; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D015203:Reproducibility of Results; D012676:Senna Extract; D000081226:Sennosides; D012680:Sensitivity and Specificity; D013607:Tablets / Q000737:chemistry*
chemical_list: D000880:Anthraquinones; D002021:Buffers; D000081226:Sennosides; D013607:Tablets; D012676:Senna Extract