Degradation pathway for eplerenone is established as per ICH recommendations by validated and stability-indicating reverse phase liquid chromatographic method. Eplerenone is subjected to stress conditions of acid, base, oxidation, and thermal and photolysis. Significant degradation is observed in acid and base stress conditions. Four impurities are studied and the major degradant (RRT about 0.31) was identified by LC-MS and spectral analysis. The stress samples are assayed against a qualified reference standard and the mass balance is found close to 99.5%. Efficient chromatographic separation is achieved on a Waters symmetry C18 stationary phase with simple mobile phase combination delivered in gradient mode and quantification is carried at 240？nm at a flow rate of 1.0？mL？min？1. In the developed LC method the resolution between eplerenone and four potential impurities (imp-1, imp-2, imp-3, and imp-4) is found to be greater than 4.0. Regression analysis shows an value (correlation coefficient) of greater than 0.999 for eplerenone and four potential impurities. This method is capable to detect the impurities of eplerenone at a level of 0.020% with respect to test concentration of 1.0？mg？mL？1 for a 20？μL injection volume. The developed UPLC method is validated with respect to specificity, linearity and range, accuracy, precision, and robustness for impurities and assay determination. 1. Introduction Eplerenone, pregn-4-ene-7, 21-dicarboxylic acid, 9, 11-epoxy-17-hydroxy-3-oxo, γ-lactone, methyl ester (7α, 11α, 17α), is an aldosterone antagonist used as an adjunct in the management of chronic heart failure. It is similar to the diuretic spironolactone, though it may be more specific for the mineralocorticoid receptor. Eplerenone is used alone or in combination with other medications to treat high blood pressure. Eplerenone is in a class of medications called mineralocorticoid receptor antagonists. It works by blocking the action of aldosterone, a natural substance in the body that raises blood pressure. Eplerenone blocks the actions of the hormone aldosterone in the body. Aldosterone is important for the regulation of blood pressure. Eplerenone (other names include SC-66110, CGP-30083, and epoxymexrenone) is the first agent to block the mineralocorticoid receptor with a high degree of selectivity and is under development for human therapeutic use in the 4 treatment of hypertension and heart failure post myocardial infarction [1–5]. A few chromatographic methods have appeared in the literature for the quantification of eplerenone in using SPE-LC-MS/MS for
References
[1]
B. Pitt, W. Remme, and F. Zannad, “Eplerenone post acute myocardial infarction heart failure efficacy and survival study investigators,” ACC Current Journal Review, vol. 12, no. 4, p. 57, 2003.
[2]
E. Burgess, J. Niegowksa, K.-W. Tan, M. S. Kipnes, B. Roniker, and J. L. Patrick, “OR-51: antihypertensive effects of eplerenone and enalapril in patients with essential hypertension,” American Journal of Hypertension, vol. 15, no. 4, supplement 1, p. A23, 2002.
[3]
M. A. Olayioye, I. Beuvink, K. Horsch, J. M. Daly, and N. E. Hynes, “ErbB receptor-induced activation of Stat transcription factors is mediated by Src tyrosine kinases,” The Journal of Biological Chemistry, vol. 274, no. 24, pp. 17209–17218, 1999.
[4]
H. Steven Wiley and P. M. Burke, “Regulation of receptor tyrosine kinase signaling by endocytic trafficking,” Traffic, vol. 2, no. 1, pp. 12–18, 2001.
[5]
B. A. Pearlman, A. G. Padilla, J. T. Hach, J. L. Havens, and M. D. Pillai, “A new approach to the furan degradation problem involving ozonolysis of the trans-enedione and its use in a cost-effective synthesis of eplerenone,” Organic Letters, vol. 8, no. 10, pp. 2111–2113, 2006.
[6]
J. Y. Zhang, D. M. Fast, and A. P. Breau, “Development and validation of a liquid chromatography-tandem mass spectrometric assay for Eplerenone and its hydrolyzed metabolite in human plasma,” Journal of Chromatography B, vol. 787, no. 2, pp. 333–344, 2003.
[7]
V. Rane, K. Patil, J. Sangshetti, R. Yeole, and D. Shinde, “Stability-indicating RP-HPLC method for analysis of eplerenone in the bulk drug and in a pharmaceutical dosage form,” Acta Chromatographica, vol. 21, no. 4, pp. 619–629, 2009.
[8]
International Conference on Harmonization, “Validation of analytical procedures: text and methodology Q2 (R1),” in International Conference on Harmonization, IFPMA, Geneva, Switzerland, 2005.
[9]
International Conference on Harmonization, “Stability testing of New Drug Substances and Products Q1 (R2),” in International Conference on Harmonization, IFPMA, Geneva, Switzerland, 2000.
[10]
International Conference on Harmonization, “Photo stability testing of new drug substances and products Q1B,” in International Conference on Harmonization, IFPMA, Geneva, Switzerland, 1996.
[11]
S. Singh and M. Bakshi, “Guidance on Conduct of Stress tests to determine inherent stability of drugs,” Pharmaceutical Technology Online, pp. 1–24, 2000.
[12]
International Conference on Harmonization, “Guidelines on validation of analytical Procedures definitions and terminology Q2A,” in International Conference on Harmonization, IFPMA, Geneva, Switzerland, 2005.
[13]
J. T. Carstensen and C. T. Rhodes, Drug Stability: Principles and Practices, Informa Healthcare, 3rd edition, 2000.
[14]
M. Bakshi and S. Singh, “Development of validated stability-indicating assay methods—critical review,” Journal of Pharmaceutical and Biomedical Analysis, vol. 28, no. 6, pp. 1011–1040, 2002.
[15]
The United States Pharmacopeia.Validation of Compendial Methods, 32nd edition, 2008.
[16]
International Conference on Harmonization, “Stability testing of new drug substances and products Q1 A (R2),” in International Conference on Harmonization, IFPMA, Geneva, Switzerland, 2003.
