INTRODUCTION:

Lercanidipine hydrochloride is chemically described as 3-O-[1-[3, 3-diphenylpropyl (methyl) amino]-2-methylpropan-2-yl] 5-O-methyl 2, 6-dimethyl-4-(3-nitrophenyl)-4dihydropyridine-3, 5-dicarboxylate hydrochloride. It is a new third generation Calcium antagonist used in the treatment of hypertension^[1].The drug is official in Merck index^[2] and Martindale^[3]. The literature survey reveals that only few methods have been reported for the determination of Lercanidipine hydrochloride including UV spectrophotometric^[4-5], LC–ESI–MS/MS ^[6], HPLC ^[7-8], Voltammetric method^[9] etc. However no suitable UV spectrophotometric method is reported till date for the estimation of Lercanidipine hydrochloride. In the present study a simple, accurate and precise spectrophotometric methods have been developed for the estimation of Lercanidipine hydrochloride in tablet dosage form.

MATERIALS AND METHODS:

Double beam spectrophotometer 2203 (Systronic) was used to measure absorbance of the resulting solution. Analytical grade solvents were used in the present study. Drug sample of Lercanidipine was procured from Orchid Healthcare Ltd. Chennai. Commercial tablets of Lercanidipine were purchased from the local market

Determination of linearity range:

Weighed accurately 25 mg of Lercanidipine hydrochloride R.S, transferred into a 25 ml standard flask, dissolved, and made up to the volume with methanol. The final solution had a concentration of 1000mg/ml (solution A). Accurately pipetted out 5 ml of solution A into a 50 ml standard flask and the volume was made up to 50 ml using methanol to get a concentration of 100mg/ml (solution B). Accurately pipetted out 2,4,6,8,10 and 12ml of lercanidipine hydrochloride standard solution ( solution B) into six numbered 50 ml standard flasks and the volume was made up to mark with methanol to get a concentration of 4,8,12,16,20 and 24 µg/ml. The absorbance of each solution was measured at 356 nm with methanol as blank. Calibration curve was plotted between absorbance vѕ concentration. (Figure2). Lercanidipine showed linearity range from 4-24 µg/ml at the selected wavelength. Optical characteristics are presented in table-1.

Analysis of Lercanidipine hydrochloride:

Twenty tablets were accurately weighed and finely powdered in a glass mortar. A weight equivalent to 25 mg was accurately weighed out and transferred to a 25ml stoppered tube. 5ml of methanol was added and swirled gently for a period of 10 minutes. Allowed to settle. The clear supernatant solution was then transferred into a 25ml standard flask through a Whatmann No.1 filter paper. The residue was further extracted twice, with5ml each of methanol and passed through the same filter paper and the volume was finally made up to 25ml with methanol. The resulting solution had a concentration of 1000mg/ml (solution A).Accurately pipetted out 5 ml of the above solution and transferred to a 50ml standard flask and made up to volume with methanol. The final solution had a concentration of 100mg/ml (Solution B). Accurately pipetted out 6, 8 and 10ml of (solution B) into each of two 50ml standard flasks and made up to the volume with methanol.The solutions had a final concentration of 12µg/ml, 16µg/ml and 20µg/ml respectively. The absorbance of each solution was measured at 356nm using methanol as blank (Figure 1).

RECOVERY STUDIES:

Recovery studies were carried out at three different levels by adding 12, 16 and 20μg/ml of pure drug solution to different samples of tablet powder solution containing the equivalent 10mg/ml of drug. From the amount of drug found, percentage recovery was calculated (Table 2).

Fig 1: UV spectrum of Lercanidipine hydrochloride

Table 1: Optical characteristics and precision data of Lercanidipine hydrochloride

PARAMETER

VALUE

λ max(nm)

Beer’s law limit (μg/m)

Molar absorptivity(L/mol cm)

Correlation coefficient (R)

Sandell sensitivity (μg/cm²/0.001AU)

Regression equation(y=mx+c)

Intercept (a)

Slope (b)

356

4–24

2.9×10⁴

0.999

0.02173

y = 0.0113x-0.0009

-0.0009

0.0113

Fig 2: Calibration curve of lercanidipine hydrochloride

Table-2: Results of the estimation of lercanidipine hydrochloride

Tablet Formulation

Label claim

(mg/tablet)

Amount found

(mg)

Recovery

(%)

RSD %

Tablet 1

9.81

98.03

0.022

Tablet 2

9.82

98.06

0.018

RESULTS AND DISCUSSION:

The proposed method for determination of lercanidipine showed linear regression of absorbance on concentration gave the equation y = 0.0113x-0.0009 , with a correlation (R) of 0.999. Lercanidipine exhibited maximum absorption at 356 nm and obeyed Beer’s law in the range of 4-24µg/ml. The percentage recovery value 98.03% and 98.06% indicates there is no interaction of the excipients present in the formulations. The study was made to test ruggedness of the method through an interday and intraday analysis of samples.

CONCLUSIONS:

Based on the results obtained, it is found that the proposed method of analysis is accurate, precise, reproducible and economical and can be employed for the routine quality control of Lercanidipine in pharmaceutical formulations.

ACKNOWLEDGEMENT:

The authors are thankful to the Director of K.M.C.H. College of Pharmacy for providing facility regarding work.

REFERENCES:

1. McClellan K J and Jarvis B, Drugs. 60,2000 , 1123.

2. Budavari S, Merck Index.12,2000.

3. Reynolds F E J, Martindale The extra Pharmacopoeia.32,1999.

4. G. Mubeen, Damanjit Singh Rao, Kadri Uvesh, Spectrophotometric Method for Determination of Lercanidipine in Tablets, International Journal of ChemTech Research.1,4,2009, 1186-1188.

5. T Manikya Sastry, K Ramakrishna, New Spectrophotometric Method of estimation of Lercanidipine Hydrochloride,Indian Journal of Chemical Technology.16,2009,431-436.

6. Jessica Fiori, Roberto Gotti, Carlo Bertucci and Vanni Cavrini, Investigation on the photochemical stability of lercanidipine and its determination in tablets by HPLC–UV and LC–ESIMS/MS, Journal of Pharmaceutical and Biomedical Analysis .1,41,2006, 176-181.

7. S. Mihaljica, D. Radulovi , J. Trbojevi, Determination of Lercanidipine Hydrochloride and Its Impurities in Tablets , Chromatographia.61, 2005,25-29.

8. A. Alvarez-Lueje, S. Pujol , J. A. Squella and L. J.Nunez-Vergara, A selective HPLC method for determination of lercanidipine in tablets , Journal of Pharmaceutical and Biomedical Analysis.31,1,2003,1-9.

9. A. Alvarez-Lueje , L. J. Nunez-Vergara, S. Pujol,J. A. Squella , Voltammetric Behavior of Lercanidipine and Its Differential Pulse Polarographic Determination in Tablets, Electroanalysis, 14,15,1098 – 1104,2002.

Received on 16.02.2012 Modified on 28.02.2012

Research J. Pharm. and Tech. 5(3): Mar.2012; Page 438-439