Research Article Quantitative Determination of Lercanidipine Enantiomers in Commercial Formulations by Capillary Electrophoresis Luciana Pereira Lourenço, 1 Fernando Armani Aguiar, 1 Anderson Rodrigo Moraes de Oliveira, 2 and Cristiane Masetto de Gaitani 1 1 Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences of Ribeir˜ ao Preto, University of S˜ ao Paulo, 14040-903 Ribeir˜ ao Preto, SP, Brazil 2 Departament of Chemistry, Faculty of Philosophy, Sciences and Letters of Ribeir˜ ao Preto, University of S˜ ao Paulo, 14040-901 Ribeir˜ ao Preto, SP, Brazil Correspondence should be addressed to Cristiane Masetto de Gaitani; crisgai@fcfrp.usp.br Received 11 December 2014; Revised 18 February 2015; Accepted 18 February 2015 Academic Editor: Sibel A. Ozkan Copyright © 2015 Luciana Pereira Lourenc ¸o et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. An enantioselective method based on capillary electrophoresis (CE) using cyclodextrin (CD) as chiral selector was developed and validated for determination of lercanidipine (LER) enantiomers, a drug calcium channel blocker which exerts antihypertensive efects of long duration, in a pharmaceutical formulation. Optimum separation of LER enantiomers was obtained on a 50cm × 50 m id capillary using a sodium acetate bufer solution 200 mmol/L pH 4.0 containing 10 mmol/L of 2,3,6-o-methyl-- cyclodextrin (TM--CD) as background electrolyte. Te capillary temperature and voltage were 15 ∘ C and 25kV, respectively, hydrodynamic injection and detection at 237 nm. Linearity was obtained in the range 12.5–100 g/mL for both enantiomers ( ≥ 0.995). Te RSD (%) and relative errors (, %) obtained in precision and accuracy studies (intraday and interday) were lower than 5%. Afer validation, the method was applied to quantify the enantiomers of LER in commercial tablets and the results were satisfactory in terms of accuracy and precision, both less than 5%. Terefore, this method was found to be appropriate for enantioselective quality control of LER enantiomers in pharmaceutical formulations. 1. Introduction Lercanidipine (LER), (±) 2-[(3,3-diphenylpropyl)methyl- amine]-1,1-dimethylethyl methyl 1,4-dihydro-2,6-dimethyl- 4-(3-nitrophenyl)-3,5 pyridinedicarboxylic ester (Figure 1), is a dihydropyridine type calcium-channel blocker known to efectively and safely reduce high levels of blood pressure, with a low adverse efect [1, 2]. Te calcium channel antag- onists inhibit the infux of calcium ions through voltage- operated calcium channels located in the cell membrane [3– 5]. Te chemical structure of LER is characterized by the presence of a side chain containing a 3,3-diphenylpropyl- methylamine-2-methyl-2-propyl group that was introduced to improve the lipophilic properties and the activity duration of the drug. Owing to the presence of asymmetric ester moieties, LER has a chiral carbon atom in position 4 of the dihydropyridine ring (Figure 1)[6]. It is commercially available as a racemic mixture of (R)- and (S)-enantiomer. Te pharmacological efects of the enantiomers of LER essen- tially resides in the (S)-enantiomer. Studies in vitro showed that (S)-enantiomer has about 100–200 times higher afnity for calcium channels than the (R)-enantiomer. Consequently, the pharmacological efects of LER are mainly related to the (S)-enantiomer [7–9]. Since the fact that many enantiomers of racemic drugs may exhibit diferences in pharmacological efects, there is a need for the development of enantioselective methods [10– 12]. To the occurrence enantioselective separation to chiral analytes, the use of chiral selectors is necessary. Te main chiral selector is cyclodextrins (CD) for possessing several properties that make them attractive, such as low UV absorp- tion, solubility and diferent polarity, and high degree of Hindawi Publishing Corporation Journal of Analytical Methods in Chemistry Volume 2015, Article ID 294270, 9 pages http://dx.doi.org/10.1155/2015/294270