Ezetimibe, which selectively inhibits cholesterol absorption across the intestinal wall and is used as an antihyperlipidemic agent, is synthesized for commercial use as a drug substance in highly pure form. During the synthetic process development studies of ezetimibe, an impurity was detected in the final product at levels ranging from 0.05% to 0.15% in reverse phase gradient high performance liquid chromatography (HPLC) method and its molecular weight was determined by LC–MS analysis. The impurity was identified as (3R,4S)-3-((S)-3-(4-fluorophenyl)-3-hydroxypropyl)-4-(4-hydroxyphenyl)-1-phenylazetidin-2-one which is called desfluoro ezetimibe (lactam-related) impurity, synthesized and characterized, the mechanism of its formation was discussed in detail. After all standardization procedures, it was used as a reference standard during validation of HPLC method and routine analyses. In addition, content of Eze-1 desfluoro impurity in Eze-1 intermediates was specified as 0.10% to keep the formation of desfluoro ezetimibe impurity under control and the related substances HPLC method was validated accordingly.
1. Bari SB, Kadam BR, Jaiswal Jaiswal, Shirkhedkar AA. Impurity profile: significance in active pharmaceutical ingredient. Eurasian J Anal Chem. 2007; 2: 32–53.
2. Gajjar AK, Shah VD. Impurity profiling: a case study of ezetimibe. Open Conferen Proceed J. 2011; 2: 108–112. http://dx.doi.org/10.2174/2210289201102010108
3. Ayre A, Varpe D, Nayak Nayak, Vasa N. Impurity profiling of pharmaceuticals. Adv Res Pharm Biol. 2011; 1: 76–90.
4. Pai NR, Sawant SS. Development and validation of new RP–HPLC method for determining impurity profiling in olmesartan medoxomil drug as well as in tablet dosage forms. Der Pharma Chemica. 2013; 5: 274–281.
5. Krishna MV, Madhavi G, Rama Prasad LA, Sankar DG. Impurity profiling of famotidine in bulk drugs and pharmaceutical formulations by RP-HPLC method using ion pairing agent. Der Pharmacia Lettre. 2010; 2: 1–11.
6. International Conference on Harmonization. Guideline on Impurities in New Drug Products, Q3B (R2), 2006.
7. ICH Topic Q3 A. Impurities Testing Guideline: Impurities in New Drug Substances. The European Agency for the Evaluation of Medicinal Products Human Medicines Evaluation Unit: 1995.
8. Wani YB, Patil DP. An experimental design approach for optimization of spectrophotometric method for estimation of cefixime trihydrate using ninhydrin as derivatizing reagent in bulk and pharmaceutical formulation. J Saudi Chem Soc; in press. http://dx.doi.org/10.1016/j.jscs.2013.11.001
9. Patel NV, Patel JK, Shah SH. Box-Behnken experimental design in the development of pectin-compritol ATO 888 compression coated colon targeted drug delivery of mesalamine. Acta Pharm. 2010; 60: 39–54. http://dx.doi.org/10.2478/v10007-010-0008-9[PubMed]
10. Pasma SA, Daik R, Maskat Maskat, Hassan O. Application of Box-Behnken design in optimization of glucose production from oil palm empty fruit bunch cellulose. Int J Pol Sci. 2013; 104502http://dx.doi.org/10.1155/2013/104502
11. Ramakrishna VS, Sudha Lakshmi PB, Ravi Kumar D, Ram Babu C. Spectrophotometric determination of valacyclovir HCl through oxidative coupling reaction in bulk and its pharmaceutical preparations. Int J ChemTech Res. 2012; 4: 138–142.
12. Srihari G, Reddy NUM, Reddy Reddy, Chakravarthi IE. A simple spectrophotometric determination of valacyclovir in pharmaceutical preparations. J Curr Chem Pharm Sci. 2011; 1: 15–18.
13. Jadhav AS, Pathare DB, Shingare MS. Development and validation of enantioselective high performance liquid chromatographic method for valacyclovir, an antiviral drug in substance. J Pharm Biomed Anal. 2006; 43: 1568–1572. http://dx.doi.org/10.1016/j.jpba.2006.11.018[PubMed]
14. Rao SK, Sunil M. Stability indicating liquid chromatographic method for valacyclovir. Int J ChemTech Res. 2009; 1: 702–708.
15. Palacios ML, Demasi G, Pizzono Pizzono, Seall AI. Validation of an HPLC method for the determination of valacyclovir in pharmaceutical Dosage. J Liq Chromatogr Rel Technol. 2005; 28: 751–762. http://dx.doi.org/10.1081/JLC-200048898
16. Patil G, Yeole PG, Puranik Puranik, Wadher SJ. A validated specific reverse phase liquid chromatographic method for the determination of valacyclovir in the presence of its degradation products in bulk drug and in tablet dosage forms. Int J ChemTech Res. 2009; 1: 16–26.
17. Rao PN, Rajeshwari KR, Rao Rao, Seshagiri Rao JVLN. RP–HPLC Estimation of Valacyclovir in Tablets. Asian J Chem. 2006; 18: 2552–2556.
18. Rasool SK, Naik DV, Prasad Prasad, Buchi NN. RP–HPLC method for the estimation of valacyclovir in bulk and pharmaceutical formulations. Int J Pharm Pharm Sci. 2012; 4: 214–218.
19. Reddy JS, Maqsood Ahmed MS, Chakravarthi IE, Prabhavathi K. Spectrophotometric estimation of valacyclovir in pharmaceutical preparations. J Chem Pharm Res. 2011; 3: 773–776.
20. Al Azzam KM, Saad B, Makahleah A, Aboul-Enein HY, Elbashir AA. Assay and stability-indicating micellar electrokinetic chromatography method for the simultaneous determination of valacyclovir, acyclovir and their major impurity guanine in pharmaceutical formulations. Biomed Chromatogr. 2010; 24: 535–543. http://dx.doi.org/10.1002/bmc.1323[PubMed]
21. Sugumaran N, Bharathi V, Hemachander Hemachander, Lakshmi M. RP–HPLC method for the determination of valacyclovir in bulk and pharmaceutical formulation. Der Pharma Chemica. 2011; 3: 190–194.
22. Sheetal Ramya LNA. Method development and validation of valacyclovir in bulk and tablet dosage form by RP–HPLC method. IOSR J Pharm Biol Sci. 2013; 5: 56–75.
23. Bandla J, Gorja A. Method development and validation of valacyclovir hydrochloride assay by RP–HPLC in pharmaceutical dosage forms. Int J Adv Res Pharm Biosci. 2013; 3: 33–41.