1. Low level determinations of methyl methanesulfonate and ethyl methanesulfonate impurities in Lopinavir and Ritonavir Active pharmaceutical ingredients by LC/MS/MS using electrospray ionization
P R Kakadiya, B Pratapa Reddy, V Singh, S Ganguly, T G Chandrashekhar, D K Singh J Pharm Biomed Anal. 2011 May 15;55(2):379-84. doi: 10.1016/j.jpba.2011.01.039. Epub 2011 Feb 24.
Methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS) have been highlighted as potential genotoxic impurities (PGIs). A sensitive LC/MS/MS method is developed and validated for the determination of MMS and EMS impurities in both Lopinavir and Ritonavir Active pharmaceutical ingredient. Method utilizes, Atlantis T3 column with electrospray ionization in multiple reactions monitoring (MRM) mode for quantitation of impurities. The proposed method is specific, linear, accurate and precise. The calibration curves show good linearity over the concentration range of 0.01-0.23 μg/mL for MMS and 0.005-0.23 μg/mL for EMS. The correlation coefficient obtained is >0.99 in each case. Method has very low limit of detection (LOD) and quantification (LOQ). LOD and LOQ of MMS and EMS are as low as ~0.002 μg/mL and ~0.01 μg/mL respectively. Method has accuracy within 80-120% for both the analytes. This method is a good quality control tool for quantitation of MMS and EMS impurities at very low levels in Lopinavir and Ritonavir.
2. Simultaneous Determination of Impurities of Atazanavir and Ritonavir in Tablet Dosage Form by Using Reversed-Phase Ultra Performance Liquid Chromatographic Method
Murali Krishna V V N Mantripragada, Sumathi V Rao, Venugopal V S Nutulapati, Bhaskara P V Mantena J Chromatogr Sci. 2018 Mar 1;56(3):270-284. doi: 10.1093/chromsci/bmx110.
A simple, rapid, selective and stability indicating reversed phase-ultra performance liquid chromatography method was developed and validated for the simultaneous quantification of process related and degradation impurities present in Atazanavir and Ritonavir tablets. The two proposed drug components and their respective impurities were separated using Acquity BEH C18 (100 mm × 2.1 mm), 1.7 μ column at a flow rate of 0.4 mL/min. Buffer used as Mobile phase-A which consists of 0.01 M monobasic potassium hydrogen phosphate adjusted the pH to 3.6 and acetonitrile is used as organic modifier (mobile phase-B). The detector wavelength of 240 nm was used for quantifying the impurities. Both the drug components along with their impurities were eluted within a runtime of 18 min. The performance of the developed method was checked by validating the method according to the requirements of International Conference on Harmonization for parameters such as specificity, precision, linearity, ruggedness, accuracy, sensitivity (limit of detection (LOD) and limit of quantitation (LOQ)) and robustness. Linearity and range were established from LOQ level to 150% level. Accuracy of the method was demonstrated from LOQ level to 150% level. The developed stability indicating method is capable for determination of impurities of Atazanavir and Ritonavir in combined tablet dosage form as well as individual dosage forms also. The reported method enables lesser solvent consumption and reduces time and cost of the analysis in quality control laboratory.
3. Development and validation of a selective, sensitive and stability indicating UPLC-MS/MS method for rapid, simultaneous determination of six process related impurities in darunavir drug substance
Vijaya Bhaskar Reddy A, Zulkifli Yusop, Jafariah Jaafar, Azmi B Aris, Zaiton A Majid, Khalid Umar, Juhaizah Talib J Pharm Biomed Anal. 2016 Sep 5;128:141-148. doi: 10.1016/j.jpba.2016.05.026. Epub 2016 May 18.
In this study a sensitive and selective gradient reverse phase UPLC-MS/MS method was developed for the simultaneous determination of six process related impurities viz., Imp-I, Imp-II, Imp-III, Imp-IV, Imp-V and Imp-VI in darunavir. The chromatographic separation was performed on Acquity UPLC BEH C18 (50 mm×2.1mm, 1.7μm) column using gradient elution of acetonitrile-methanol (80:20, v/v) and 5.0mM ammonium acetate containing 0.01% formic acid at a flow rate of 0.4mL/min. Both negative and positive electrospray ionization (ESI) modes were operated simultaneously using multiple reaction monitoring (MRM) for the quantification of all six impurities in darunavir. The developed method was fully validated following ICH guidelines with respect to specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision, robustness and sample solution stability. The method was able to quantitate Imp-I, Imp-IV, Imp-V at 0.3ppm and Imp-II, Imp-III, and Imp-VI at 0.2ppm with respect to 5.0mg/mL of darunavir. The calibration curves showed good linearity over the concentration range of LOQ to 250% for all six impurities. The correlation coefficient obtained was >0.9989 in all the cases. The accuracy of the method lies between 89.90% and 104.60% for all six impurities. Finally, the method has been successfully applied for three formulation batches of darunavir to determine the above mentioned impurities, however no impurity was found beyond the LOQ. This method is a good quality control tool for the trace level quantification of six process related impurities in darunavir during its synthesis.
