Supplementary Material

Transcription

1 Supplementary Material Development and validation of an HPLC method for simultaneous determination of ibuprofen and 17 related compounds Zunsheng Han 1, Liping Lu 1, Lin Wang 1, Zimeng Yan 2, Xiayan Wang 1 1 College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, People s Republic of China 2 Qilu Pharmaceutical (Hai Nan) Co., Ltd., Haikou, Hainan, People s Republic of China *Corresponding author: Prof. Dr. Xiayan Wang, xiayanwang@bjut.edu.cn Dr. Zimeng Yan, zimeng.yan@qilu-pharma.com

2 UV absorbance 1. Optimization of HPLC method 1) UV wavelength optimization: Figure S1. The UV spectra of IBU and 17 related compounds of 0.2 mg ml -1 within nm range are presented in the following figure. The 214 nm detection wavelength was selected because most of these compounds have similar or comparable UV absorption or strength. Imp-A Imp-B Imp-C Imp-D Imp-E Imp-F 2.4 Imp-G Imp-H Imp-I 1.8 Imp-J Imp-K Imp-L Imp-M Imp-N Imp-P Imp-Q Imp-R IBU

3 2) Buffer ph optimization: Since IBU has a reported pk a value of 4.41 ± 0.10 [1], the ph value of the solution should be at outside of the IBU pk a value plus or minus units. In order to find the optimal ph value for the best overall separation, we evaluated both the lower ph range and the higher ph range of the mobile phases. It was found that in the lower ph range (ph 2 5), a number of the impurities and IBU were inseparable. In contrast, in the higher ph range (ph ) of the phosphate solution, those impurities were separated better, and the mobile phases at ph 6.9 resulted in the best separation. 3) Gradient and columns: Considering the practicability of the method and the particularity of the system, we choose the most common column. The differences include the column length, diameter, filler particle size. After repeated experiments, we found that it is difficult for short column to have a good separation, besides, smaller particle size will bring greater back pressure. Compared to selecting a column, we developed a HPLC method that pays more attention to the choice of ph, as well as the gradient settings. For different columns, we have done a lot of optimization gradient conditions. At last, the ZORBAX Eclipse Plus ( mm, 5 μm) column provided the best selection and robustness, the HPLC gradient was programmed (time, %B) as following: (1) 0 min, 18%B; (2) 31 min, 29%B; (3) 40 min, 96%B; (4) 60 min, 96%B. Time of column equilibration was 10 min. See Table S1.

4 Table S1. HPLC method to develop the relevant parameters and separation results Columns WondaSil -WR ( mm, 5 μm) Phenomenex Luna 3u (2) ( mm, 3 μm) Waters Atlantis T3 () ( mm, 3 μm) Phenomenex Kinetex F5 ( mm, 2.6 μm) ZORBAX Eclipse Plus ( mm, 5 μm) Stationary Phases Mobile phases F5 (Pentafluorophenyl) Gradients (Time/%B) 0/13; 35/32; 45/95; 60/95. 0/12; 32/33; 44/90; 70/90. 0/15; 20/25; 60/85; 75/93; 95/93. 0/12; 28/28; 29/75; 60/75. 0/18; 31/29; 40/96; 60/96. ph values Flow rates (ml min -1 ) Temperature ( C) Unseparated items IBU and Imp-A IBU and Imp-A IBU and Imp-A, B Imp-D and Imp-L, peak shape and durability is poor, Completely separated In our study, five columns from with different specifications from different manufacturers evaluated. The final column and other parameters were selected based on the results of separation, peak shape, ruggedness, running time, etc. Analysis time (min)

5 Intensity (uau) Intensity (uau) Figure S2. Typical HPLC chromatograms of (a) 2 mg ml -1 IBU tablet of batch 6; (b) mg ml -1 IBU spiked with the 17 impurities at the level of 0.1% IBU 2000 (b) K DL J N M A B FG C QPE H R I 0 (a) J A F E R Time (min) Figure S3. Verify robustness at different ph. (a) ph6.8; (b) ph6.9; (c) ph (c) (b) K DL J N M A IBU B FG C QP E H R I (a) Time (min)

6 References [1] Kalafut P, Kucera R, Klimes J, Sochor J (2009) An innovative approach to the analysis of 3-[4-(2-methylpropyl)phenyl] propanoic acid as an impurity of ibuprofen on a carbon-coated zirconia stationary phase. J Pharm Biomed Anal 49: