PhD Theses STUDY OF THE SOLVENT GRADIENT SIMULATED MOVING BED PREPARATIVE LIQUID CHROMATOGRAPHIC PROCESS Written by Melinda Nagy Consultants Tibor Szánya Géza Horváth University of Pannonia Department of Chemical Engineering Science Veszprém 2009
BACKGROUND AND OBJECTIVES Nowadays the production of API s (Active Pharmaceutical Ingredients) with high purity is a basic requirement. To fulfill the strict quality specifications the batch preparative liquid (HPLC) and the continuous simulated moving bed chromatography (SMB) techniques are getting higher and higher significance. Previously most of the industrial-scale SMBs used the original isocratic method. Recent developments focus on the current procedure s technical improvement. Gedeon Richter Plc. is one of the biggest pharmaceutical company in Hungary, dealing with research, development, manufacture and marketing of human drugs, active substances and intermediates. Both in manufacturing and in research the company applies up to date chemical engineering processes. Gedeon Richter Plc. in cooperation with the Department of Chemical Engineering Sciences, University of Pannonia and the Department of Informatics, University of Kaposvár applied in 2002 for the Széchenyi Plan National Research and Development Program of the Ministry of Education. The title of the winning application was Introduction of New Cleaner Chromatographic Processes into the Pharmaceutical Industry. The goal of the project, which was led by the Department of Chemical Engineering Science at the University of Pannonia by the request of Gedeon Richter Plc., was to develop the separation method of a two-component non-isomer steroid mixture with simulated moving bed chromatographic process, using silicagel as adsorbent and a mixture of acetone and dichloro-methane as eluent. The next phase of research was to select those operational parameters which assure the best conditions for industrial realization taking into account economic and quality management aspects. The current direction in SMB research is the gradient SMB, where the concentration change of the gradient solvent along the length of the SMB equipment has significant importance. The solvent gradient SMB chromatographic process could be a promising separation method to find the optimal operational point for a given separation task, when the separation is successful, the productivity is maximal, and the fresh solvent consumption is minimal. 1
In our case the application of the gradient system seemed to be realizable, as during the evaluation of the isocratic measurements it turned out, that the system had a specific feature. Namely the acetone, the solvent for gradient used for the separation had changing distribution along the length of the equipment, the so called self-gradient. My PhD Theses deals with this problem and investigates the system with the help of computer simulations, and experimentally with laboratory equipment. Simulation software provided great advantage during the work, and simulation had been done for numerous material stream systems. The adsorption model was based on competitive-langmuir-isotherm. The software calculates the concentration versus time and distance; the calculated results are stored in files. The software is able to work with a system, where the number of columns can be maximum 20. Linear, competitive-langmuir or competitive bi-langmuir isotherms can be used during simulation. Based on the best simulation results SMB measurements were done with the best, promising parameters. Within the frame of the doctoral dissertation the separation of a two-component steroid mixture was investigated. The separation factor of the two steroids B is the less-retained and A is the A more-retained is α = 2.18 which is appropriate, therefore, the simulated moving bed B chromatographic separation process is well feasible. The ratio of components (A:B) was 20:80 m/m%. I tried to improve the separation with the use of fresh solvent gradient step. In our system acetone adsorbs on the silicagel packing having influence on the components A, B to be separated and acetone, dichloro-methane in liquid phase. Acetone helps desorption of the strongly retaining component A, and separation. The investigation of the problem has two directions: a) To search for possible optimization of the extreme value in the system technically feasible and economically reasonable. b) To analyze the effect of solvent composition, as operating parameter sensitivity investigation. In case of option a) we can reduce the fresh solvent consumption and generate concentrated products. In case of b) we could identify those problems which might jeopardize the normal operation. In my PhD theses I deal with this gradient SMB-LC focusing on the determination of optimal cost minimized operating parameters and the goal is to produce the less retained compound ( B ) with purity higher than 99.9 m/m%, beside higher than 90 % yield. This separation process has got industrial importance. EXPERIMENTAL AND EVALUATION METHODS Equilibrium measurements Adsorption equilibria data were determined at the Department of Preparative Chromatography of Gedeon Richter Plc. The adsorption isotherms of acetone and the studied compounds were measured by analytical HPLC with YMC S-50 silica gel and acetone-dichloromethane eluent using Frontal Adsorption (FA) multi step method. The Langmuir model was fitted to the measured points, and the resulted Langmuir constants were used in the computer simulation. NTP, HETP measurements During the determination of NTP, HETP in 1:1 v/v% acetone:dichloro-methane eluent, on YMC S-50 silica gel column, on 300 nm wavelength was detected the inlet impulse change of the 2 v/v% acetophenone in eluent and dichloro-methane in eluent at the column outlet. We evaluated the residence time distribution function with the triangle method. NTP, HETP data determined for one of the columns (d i =1 cm) of the SMB equipment, at the flowrate in the range of 0-14 cm 3 /min were applied in the computer simulation. 2 3
Frontal Adsorption - Desorption Measurement During the frontal adsorption the mixture of 5 g (A+B)/dm 3 eluent (1:1 v/v% acetone: dichloro-methane) was fed into the YMC S-50 silica gel column within a given time, later pure eluent was fed into the column. The outlet liquid was collected in sample test tubes at 0 C, and its concentration was measured by analytical gas chromatograph. The measurement of the frontal adsorption-elution was simulated with computer software, where the acetone concentration changes were calculated beside the steroid concentrations as well. The experimental and simulation results were in good correlation. SMB Equipment Planning, Construction and Installation The SMB preparative liquid chromatographic equipment with four columns, four segments and open eluent loop was constructed in the Central Mechanic Workshop, University of Pannonia, and used in the experiments. Laboratory-scale SMB experiments With initial simulations I determined the best measurement parameters and flow rates for product requirements and economic process to reach productivity maximal and minimal eluent consumption. With the help of Morbidelli s triangle theory and based on computer simulations, SMB experiments were carried out. I investigated the feed concentration increase of steroid for separation from 5 to 10, 20, 30, 40 and 50 g/dm 3. At constant 5 g/dm 3 feed concentration I investigated the effect of fresh eluent acetone: dichloro-methane composition change on the raffinate and extract concentration. I studied various SMB techniques, namely the modulated feed, when the flow rate of the feed to be separated is changing in time. I investigated the open-loop SMB technique at column configuration 1:1:2:0 = I:II:III:IV. I studied the possibility of switching time decrease beside prescribed requirements, while improving the specifics. During the evaluation of the measured and calculated data I presented on different diagrams the concentration of the raffinate and extract streams for each steroid components and acetone in function of time. After the last two switching times, when the quasi steady-state of the system had been reached, I represented the concentrations and purities expressed in mass percentage of the components, in both streams. Comparing the first experimental and simulation results, good agreement was found. In consequence, the simulation model proved to be applicable for the actual process design and determination of suboptimal operational variables. The specific process parameters (productivity, specific solvent consumption, yield) were calculated for the raffinate and extract products while keeping purity requirements. NEW SCIENTIFIC RESULTS Thesis 1 I studied different methods of the simulated moving bed preparative chromatography, focusing on the solvent compound changing SMB method. In case of each method the goal was to define the optimal operational parameters, which met the industrial requirements (purity of the component B > 99.9 m/m%, yield of the component B > 90 %). To accomplish the process I planned a manually operated four-column SMB equipment and had it constructed. During the separation I used a non-isomer steroid mixture, where the composition of the compounds were B:A 80:20 m/m%. Thesis 2 In the first step and during the equipment set in operation I increased the feed concentration of the steroid mixture, and I observed that the concentration dependent Morbidelli-triangle was modifying significantly (narrowing). Using higher feed concentration it was necessary to decrease feed flow rate for positioning the work point inside the Morbidelli-triangle, and 4 5
for obtaining both components pure. The first SMB experimental data were compared to the results of computer simulation and agreed well with each other. The consequence is that the simulation model proved to be applicable for further process design. Thesis 3 I selected a few experiments according to the results of the simulation and determined the technical optimum in gradient SMB method, changing the fresh eluent compounds concentration. According to the experiments I drew the next conclusions: 3.1. Increase of the acetone concentration results the movement of the Morbidelli-triangle. The increasing concentration of the acetone moves the Morbidelli-triangle on the m III = (y), m II = (x) diagram toward to the origo (y = x = 0), along the diagonal y =x. Decreasing acetone concentration the Morbidelli-triangle moves in opposite direction. The work points (m II, m III ) must not necessarily be inside the triangle area, because the triangle moves along the diagonal. Even in such cases can be reached for the purity of the component B > 99.9 m/m%, for the yield of the component B > 90 %. 3.2. The increased concentration of the acetone helps the desorption of the component A in segment I. The minimal quantity of the fresh eluent (D min ) can be decreased by 10-20 % compared to the isocratic case. 3.3. While determining gradient concentration, solubility of the components must be taken into consideration. For example, RG-1040 components dissolve well in dichloromethane, and weakly in acetone. (These considerations can help the increase of the operational specifics, e.g. P B, P A productivities). 3.4. In case of SMB separation (closed loop) the concentration of acetone is changing significantly before the switching time along the lengths of the columns. I denominated it self-gradient of acetone. This self-gradient phenomenon has not been published in the scientific literature so far. Thesis 4 I have had opportunities to analyze different SMB techniques over the gradient SMB. 4.1. Application of modulated feed (dynamic SMB, the flow rate of the feed to be separated is changing in time), improves the purity of the raffinate and extract streams. By this method I was able to increase the quantity of the feed, and I achieved significantly higher productivity and lower fresh eluent consumption compared to the previous measurements. 4.2. I concluded from the results of the SMB separations and computer simulations, that the biggest possible space had to be assured for the component B along the length of the columns to fulfill approximately 4:1=B:A ratio and K B < K A relation. In a four segmented system the biggest possible space can be reached with 1:1:2:0=I:II:III:IV opened loop column configuration. This column configuration simplifies the operation, as there is no eluent recirculation, and the parameters have to fulfill one less Morbidelli criteria. Another advantage is that operation requires only three pumps. I could reduce the fresh eluent consumption beside given productivity by extract flow rate reduction. 4.3. In the final task I studied the possibility of the reduction of the switching time beside prescribed requirements while improving the specifics. For the above purpose the work point has to be determined well. Comparing the productivity of component B of preparative HPLC measurements to other SMB measurements by the reduction of switching time it was increased with 700 %, and the consumption of fresh eluent was decreased with 50 %. 6 7
PUBLICATIONS Lectures Műszaki Kémiai Napok, Veszprém, 2002. április 16-18. Szimulált mozgóréteges (SMB) preparatív folyadékkromatográfiás műveletek vizsgálata Molnár Zoltán, Nagy Melinda, Hanák László, Szánya Tibor, Argyelán János VEAB Ipari Biotechnológiai Munkabizottsági Ülés, Veszprém, 2003. május 14. Szerves vegyületek szeparációja szimulált mozgóréteges (SMB) preparatív folyadékkromatográfiás művelettel Bernadett, Aranyi Antal, Temesvári Krisztina Elválasztástudományi Vándorgyűlés, Hévíz 2004. szeptember 22-24 Szerves vegyületek elválasztása háromszegmenses szimulált mozgóréteges (SMB) preparatív folyadékkromatográfiás művelettel Bernadett, Turza Gergely, Aranyi Antal, Temesvári Krisztina Ünnepi VMMB ülés, 2004. december 7. Szerves vegyületek elválasztása három szegmenses szimulált mozgóréteges (SMB) preparatív folyadékkromatográfiás művelettel Bernadett, Turza Gergely, Aranyi Antal, Temesvári Krisztina Posters Műszaki Kémiai Napok, Veszprém, 2003. április 8-10. Kislaboratóriumi méretű szimulált mozgóréteges (SMB) preparatív folyadékkromatográfiás készülék vizsgálata Bernadett, Aranyi Antal, Temesvári Krisztina 6 th International Symposium and Exhibition on Environmental Contamination in Central and Eastern Europe and the Commonwealth of Independent States, Prague 1-4, September, 2003 Study of a Simulated Moving Bed (SMB) Preparative Liquid Chromatographic Appliance and Technology M. Nagy, Z. Molnár, L. Hanák, J. Argyelán, T. Szánya, A. Aranyi, K. Temesvári 5 th Balaton Symposium on High Performance Separation Methods held in Siófok, Hungary, 3-5 September 2003 Separation of Organic Compounds by Simulated Moving Bed (SMB) Preparative Liquid Chromatographic Technology M. Nagy, Z. Molnár, L. Hanák, J. Argyelán, T. Szánya, A. Aranyi, K. Temesvári Műszaki Kémiai Napok, Veszprém, 2004. április 20-22. Oldószergradiensek vizsgálata szimulált mozgóréteges preparatív folyadékkromatográfiás művelettel Bernadett, Aranyi Antal, Temesvári Krisztina PREP 2004 17 th International Symposium, Exhibit, Workshops on Preparative / Process Chromatography, May 23 May 26, 2004 Baltimore, MD, USA Separation of Amino-acids with Simulated Moving Bed Chromatography Tibor Szánya, Antal Aranyi, Zoltán Molnár, László Hanák, Melinda Nagy, János Argyelán, István Pencz PREP 2005 18 th International Symposium, Exhibit, Workshops on Preparative / Process Chromatography, May 8 May 11, 2005 Philadelphia, PA, USA Separation of Organic Compunds by Simulated Moving Bed Chromatography Tibor Szánya, Antal Aranyi, Melinda Nagy, László Hanák, Zoltán Molnár, János Argyelán, Krisztina Temesvári 8 9
Articles CHROMATOGRAPHIA, Vol. 60, Suppl. (2004) PP. S181-S187 Separation of Organic Compounds by Simulated Moving Bed Preparative Liquid Chromatography M. Nagy, Z. Molnár, L. Hanák, J. Argyelán, T. Szánya, B. Ravasz, A. Aranyi, K. Temesvári CHROMATOGRAPHIA, Vol. 60, Suppl. (2004) PP. S75-S80 Simulated Moving-Bed Liquid Chromatography with Three Zones for Continuous Desalting of Organic Compounds Z. Molnár, M. Nagy, L. Hanák, T. Szánya, J. Argyelán Hungarian Journal of Industrial Chemistry, Vol. 32. pp. 23-31 (2004) Study of Open-looped Simulated Moving Bed (SMB) Chromatographic Process M. Nagy, Z. Molnár, L. Hanák, J. Argyelán, T. Szánya, B. Ravasz, G. Turza, A. Aranyi, K. Temesvári Hungarian Journal of Industrial Chemistry, Vol. 32. pp. 13-21 (2004) Investigation of ReversePhase SMB-chromatographicBioseparations of Amino Acid Aqueous Solutions Z. Molnár, M. Nagy, A. Aranyi, L. Hanák, T. Szánya, J. Argyelán Hungarian Journal of Industrial Chemistry, Vol. 34. pp. 21-26 (2006) Separation of Organic Compounds by Gradient Simulated Moving Bed Chromatography M. Nagy, T. Szánya, Z. Molnár, G. Turza, G. Gál, L. Hanák, J. Argyelán, A. Aranyi, K. Temesvári and Z. Horváth Hungarian Journal of Industrial Chemistry, Vol. 34. pp. 21-26 (2006) Quasi-Continuous Elution Chromatographic Purification of a Steroid Active Compound Temesvári K, Aranyi A, Horváth Z, Nagy M, Szánya T, Hanák L Prizes 6 th International Symposium and Exhibition on Environmental Contamination in Central and Eastern Europe, Prága (2003) Third price in Student Scholarship category 5 th Balaton Symposium on High Performance Separation Methods held in Siófok, Hungary (2003) Best Poster Award Magyar Kémiai Folyóirat. Vol. 111-2 (2005), 88-91 Szimulált mozgóréteges (SMB) preparatív folyadékkromatográfiás művelet vizsgálata laboratóriumi méret négyoszlopos készülékkel Bernadett, Turza Gergely, Aranyi Antal, Temesvári Krisztina Journal of Chromatography A, Vol. 1075, Issues 1-2 (2005), 77-86 Separation of Amino Acids with Simulated Moving Bed Chromatography Z. Molnár, M. Nagy, A. Aranyi, L. Hanák, J.Argyelán, I. Pencz, T. Szánya 10 11