A Simple and Sensitive RP-HPLC Method for Estimation of Trandolapril in Bulk and Tablet Dosage Forms

 

V. Bhaskara Raju1 and A. Lakshmana Rao2*

1Sri Vasavi Institute of Pharmaceutical Sciences, Tadepalligudem- 534 101, A.P., India.

2V.V. Institute of Pharmaceutical Sciences, Gudlavalleru- 521 356, A.P., India.

*Corresponding Author E-mail: dralrao@gmail.com

 

ABSTRACT:

An accurate and precise HPLC method was developed for the determination of trandolapril. Separation of the drug was achieved on a reverse phase C18 column using a mobile phase consisting of phosphate buffer and acetonitrile in the ratio of 35:65 v/v. The flow rate was 0.8 ml/min and the detection wavelength was 210 nm. The linearity was observed in the range of 20-60 µg/ml with a correlation coefficient of 0.999. The proposed method was validated for its linearity, accuracy, precision and robustness. This method can be employed for routine quality control analysis of trandolapril in tablet dosage forms.

 

KEYWORDS: Trandolapril, Estimation, RP-HPLC, Validation, Tablets.

 


 

INTRODUCTION:

Trandolapril1 is a non-sulhydryl prodrug that belongs to the angiotensin-converting enzyme (ACE) inhibitor class of medications. It is metabolized to its biologically active diacid form, trandolaprilat, in the liver. Trandolaprilat inhibits ACE, the enzyme responsible for the conversion of angiotensin I (ATI) to angiotensin II (ATII). ATII regulates blood pressure and is a key component of the renin-angiotensin-aldosterone system (RAAS). Trandolapril may be used to treat mild to moderate hypertension, to improve survival following myocardial infarction in clinically stable patients with left ventricular dysfunction, as an adjunct treatment for congestive heart failure, and to slow the rate of progression of renal disease in hypertensive individuals with diabetes mellitus and microalbuminuria or overt nephropathy. Trandolapril is chemically described as (2S, 3aR, 7aS)-1-[(S)-N-[(S)-1-Carboxy-3-phenylpropyl]alanyl] hexahydro-2-indolinecarboxylic acid, 1-ethyl ester (Fig. 1). A few spectroscopic2, HPLC3, LC-MS4 and HPTLC5 methods were reported earlier for the determination of trandolapril in bulk and pharmaceutical dosage forms. In the present study the authors report a rapid, sensitive, accurate and precise HPLC method for the estimation of trandolapril in bulk samples and in tablet dosage forms.

 

MATERIALS AND METHODS:

Chromatographic conditions:

The analysis of the drug was carried out on a Waters HPLC system equipped with a reverse phase Xterra C18 column (150 mmx4.6mm; 5μm), a 2695 binary pump, a 20 μl injection loop and a 2487 dual absorbance detector and running on Waters Empower software.

 

Chemicals and solvents:

The reference sample of trandolapril was supplied by Glenmark Pharmaceutical Industries Ltd., Mumbai. HPLC grade water and acetonitrile were purchased from E. Merck (India) Ltd., Mumbai. Potassium dihydrogen phosphate and orthophosphoric acid of AR Grade were obtained from S.D. Fine Chemicals Ltd., Mumbai.

 

Preparation of phosphate buffer (pH 3.0):

Seven grams of KH2PO4 was weighed into a 1000 ml beaker, dissolved and diluted to 1000 ml with HPLC water. 2 ml of triethyl amine was added and pH adjusted to 3.0 with orthophosphoric acid.

 

Preparation of mobile phase and diluents:

350 ml of the phosphate buffer was mixed with 650 ml of acetonitrile. The solution was degassed in an ultrasonic water bath for 5 minutes and filtered through 0.45µ filter under vacuum.

 

Procedure:

A mixture of buffer and acetonitrile in the ratio of 35:65 v/v was found to be the most suitable mobile phase for ideal separation of trandolapril. The solvent mixture was filtered through a 0.45μ membrane filter and sonicated before use. It was pumped through the column at a flow rate of 0.8 ml/min. The column was maintained at ambient temperature. The pump pressure was set at 800 psi. The column was equilibrated by pumping the mobile phase through the column for at least 30 min prior to the injection of the drug solution. The detection of the drug was monitored at 210 nm. The run time was set at 5 min. Under these optimized chromatographic conditions the retention time obtained for the drug was 2.732 min. A typical chromatogram showing the separation of the drug is given in Fig. 2.

 

Fig. 1: Chemical structure of trandolapril

 

Fig. 2:  Typical   chromatogram of trandolapril

 

Calibration plot:

About 10 mg of trandolapril was weighed accurately, transferred into a 100 ml volumetric flask and dissolved in 25 ml of a 35:65 v/v mixture of phosphate buffer and acetonitrile. The solution was sonicated for 15 min and the volume made up to the mark with a further quantity of the diluent to get a 100 µg/ml solution. From this, a working standard solution of the drug (40µg/ml) was prepared by diluting 4 ml of the above solution to 10 ml in a volumetric flask. Further dilutions ranging from 20-60 µg/ml were prepared from the solution in 10 ml volumetric flasks using the above diluent. 20 µl of each dilution was injected six times into the column at a flow rate of 0.8 ml/min and the corresponding chromatograms were obtained. From these chromatograms, the average area under the peak of each dilution was computed. The calibration graph constructed by plotting concentration of the drug against peak area was found to be linear in the concentration range of 20-60 µg/ml of the drug. The relevant data are furnished in Table-1. The regression equation of this curve was computed. This regression equation was later used to estimate the amount of trandolapril in tablets dosage forms.

 

Table 1. Calibration data of the method

Concentration (mg/ml)

Mean peak area (n=5)

20

1029710

30

1502392

40

1935168

50

2474029

60

2936930

 

Validation of the proposed method:

The specificity, linearity, precision, accuracy, limit of detection, limit of quantification, robustness and system suitability parameters were studied systematically to validate the proposed HPLC method for the determination of Trandolapril. Solution containing 40 µg/ml of Trandolapril was subjected to the proposed HPLC analysis to check intra-day and inter-day variation of the method and the results are furnished in Table-2. The accuracy of the HPLC method was assessed by analyzing solutions of Trandolapril at 50, 100 and 150% concentrated levels by the proposed method. The results are furnished in Table-3. The system suitability parameters are given in Table-4.

 

Table 2. Precision of the proposed HPLC method

Concentration of Trandolapril (40mg/ml)

Peak area

Intra day

Inter day

Injection-1

2021079

2069536

Injection-2

2019713

2063771

Injection-3

2020269

2065251

Injection-4

2031519

2063285

Injection-5

2041268

2065260

Average

2026770

2065421

Standard Deviation

9450.0

2463.3

%RSD

0.47

0.12

 

Table 3. Accuracy studies

Concentration

Amount added (mg)

Amount found (mg)

% Recovery

% Mean recovery

50%

20.13

20.23

100.5%

 

100.6%

100%

40.01

39.91

99.7%

150%

60.05

60.92

101.5%

 

 

Table 4. System suitability parameters

Parameter

Result

Linearity ((mg/ml)

20-60

Correlation coefficient

0.999

Theoretical plates (N)

2990

Tailing factor

1.5

LOD (mg/ml)

0.02

LOQ (mg/ml)

0.08

 

Estimation of trandolapril in tablet dosage forms:

Two commercial brands of tablets were chosen for testing the suitability of the proposed method to estimate trandolapril in tablet formulations. Twenty tablets were weighed and powdered. An accurately weighed portion of this powder equivalent to 25 mg of trandolapril was transferred into a 100 ml volumetric flask and dissolved in 25 ml of a 35:65 v/v mixture of phosphate buffer and acetonitrile. The contents of the flask were sonicated for 15 min and a further 25 ml of the diluent was added, the flask was shaken continuously for 15 min to ensure complete solubility of the drug.  The volume was made up with the diluent and the solution was filtered through a 0.45 µ membrane filter.  This solution containing 40 µg/ml of trandolapril was injected into the column six times. The average peak area of the drug was computed from the chromatograms and the amount of the drug present in the tablet dosage form was calculated by using the regression equation obtained for the pure drug. The relevant results are furnished in Table-5.

 

Table 5. Assay and recovery studies

Formulation

Label claim (mg)

Amount found (mg)

% Amount found

Formulation 1

40

40.003

100.0

Formulation 2

40

39.992

99.97

 

 

RESULTS AND DISCUSSION:

In the proposed method, the retention time of trandolapril was found to be 2.732 min. Quantification was linear in the concentration range of 20-60 µg/ml. The regression equation of the linearity plot of concentration of trandolapril over its peak area was found to be Y=61215+47860.77X (r2=0.999), where X is the concentration of trandolapril (µg/ml) and Y is the corresponding peak area. The number of theoretical plates calculated was 2990, which indicates efficient performance of the column. The limit of detection and limit of quantification were found to be 0.02 μg/ml and 0.08 μg/ml respectively, which indicate the sensitivity of the method. The use of phosphate buffer and acetonitrile in the ratio of 35:65 v/v resulted in peak with good shape and resolution.  The high percentage of recovery indicates that the proposed method is highly accurate. No interfering peaks were found in the chromatogram of the formulation within the run time indicating that excipients used in tablet formulations did not interfere with the estimation of the drug by the proposed HPLC method.

 

CONCLUSION:

The proposed HPLC method is rapid, sensitive, precise and accurate for the determination of trandolapril and can be reliably adopted for routine quality control analysis of trandolapril in its tablet dosage forms.

 

ACKNOWLEDGEMENTS:

The authors are thankful to M/s Glenmark Pharmaceutical Industries Ltd., Mumbai for providing a reference sample of trandolapril.

REFERENCES:

1.       www.drugbank.com

2.       D. Sunil Kumar. Development and validation of a new UV spectroscopic method for the determination trandolapril maleate. Pharm Expt, 2010, 1(1), 200-207.

3.       A. Gumieniczek, H. Hopkala. Development and validation of liquid chromatographic method for the determination of trandolapril and verapamil in capsules. Journal of Liquid chromatography and Related technologies, 2001, 24(3), 393-400.

4.       V.S.N. Ramakrishna, N.K. Vishwottam, W. Srivastava, M. Koteswara. Quantification of trandolapril and its metabolite trandolaprilet in human plasma by liquid chromatography/tandom mass spectroscopy using solid phase extraction. Rapid Communications in Mass Spectroscopy, 2006, 20(24), 3709-3716.

5.       Kowalczuk, Dorota. Simultaneous high performance thin layer chromatography densitometric assasy of trandolapril and verapamil in the combination preparation. Journal of AOAC International, 2005, 88(5), 1525-1529.

 

 

 

Received on 14.07.2011        Modified on 01.08.2011

Accepted on 14.08.2011        © AJRC All right reserved

Asian J. Research Chem. 4(9): Sept, 2011; Page 1425-1427