Development and Validation of Method for Quantitative Estimation of Felodipine Agglomerates by High Pressure Liquid Chromatography


Ravindra J. Jarag1* and A.R. Paradkar2

1Bharati Vidyapeeth College of Pharmacy, Kolhapur, Maharashtra India-416013

2Bharati Vidyapeeth Poona College of Pharmacy, Pune, Maharashtra India -411038

*Corresponding Author E-mail:



In present study, RP-HPLC method was developed for the quantitative estimation of Felodipine (calcium channel blocker used in the treatment of hypertension and angina pectoris) in agglomerates prepared by Crystallo-co-agglomeration technique. In RP-HPLC (binary gradient system consists of Jasco 2000 plus) method, felodipine was determined by isocratic system using methanol 0.055M phosphate buffer (83:17 v/v pH=3 ± 0.1) as mobile phase. Hydrochlorthaizide was adopted as an internal standard. Detection was carried out with UV detection at 232 nm. The proposed developed method is simple, sensitive, accurate, precise and rapid. The method is valid as per ICH guidelines.


KEYWORDS: Felodipine, Crystallo-co-agglomeration (CCA) HPLC, Quantitative estimation.




Felodipine1-2 (Fig.-1) is a calcium channel blocker used in the treatment of hypertension and angina pectoris. It is white or light yellow crystalline powder freely soluble in alcohol and DCM and practically insoluble in water. It is substituted 1, 4 dihydropyridin derivative and chemically it is ethylmethyl-1,4-dihydro-2,6-dimethyl-4-(2,3 dichloro phenyl) -3, 5 pyridindicarboxylate.


In the quantitative estimation of felodipine in body fluids and pharmaceutical dosage forms, the previous studies were realized by titrimetry, spectrophotometry, HPLC and gas-liquid chromatography from tablets. Crystallo-co-agglomeration (CCA) is a novel particle size enlargement technique developed by Pawar, et al3. used for modifying the micromeritic, mechanical, compressional, and drug release properties of various drugs4-5. So far, no RP-HPLC method was developed for felodipine agglomerates prepared by CCA6. In presence study we have developed to assay procedure (RP-HPLC) which would serve as a rapid and reliable method for the estimation of felodipine in commercial dosage form like tablet and agglomerates7.



Reagents and Chemicals:

Felodipine and Hydrochlorthaizide (internal standard) were kindly donated by Glenmark pharmaceutical, Goa (India) and Cipla Pvt. Ltd. Goa (India) respectively. Solvents and chemicals used for method development were of analytical and HPLC grade were purchased from Merck Ltd, Mumbai, (India). Double distilled Water.



HPLC binary gradient system consists of Jasco 2000 plus series delivery pump system equipped with a PU-2080 plus, UV-2075 plus detector. HIQ Sil C 18 HS Column size 4.6 mm×250 mm Kya tech. (Japan).  Peak areas were integrated automatically by a 3396 A multimode integrator.


Figure 1.  Structure of Felodipine.


Figure 2. Chromatogram of Felodipine and Hydrochlorothiazide (Internal Standard)


HPLC Method:8

Chromatographic condition:

Felodipine was determined by isocratic system with mobile phase consisting of methanol 0.055 M phosphate buffer (83:17v/v). The phosphate buffer is adjusted PH=3±0.1 with o-phosphoric acid. The mobile phase was prepared daily and filtered through membrane filter press of 0.45 μm pore size membrane and degassed for 15 min. in an ultrasonic cleaning bath (Spectra lab-Model UCB 70) before use. Flow-rate was 0.8 mL.min־1 with 20 μL injection volume at 232 nm wavelength for detection (UV detector). Hydrochlorthaizide was used as internal standard. All assays were performed at ambient temperature.


Stock solution:

The stock solution of felodipine (100 mcg mL-1) and hydrochlorthaizide (100 mcg mL-1) were prepared in mobile phase. Calibration graphs were prepared in synthetic mixtures of felodipine and hydrochlorthaizide. Standard solutions of felodipine were prepared in the concentration range of (10-60 mcg mL-1) and internal standard hydrochlorthaizide concentration was fixed in 5 µg mL-1 for all standard mixtures. All appropriate dilutions were prepared with mobile phase. 20 µL volume of each synthetic mixture was injected and all applications were repeated three times. The peak height ratios of active substances to internal standard were plotted against corresponding concentration of felodipine.


Sample preparation:

Agglomerates equivalent to 5 mg of Felodipine were weighed and powdered transferred to a 50 mL volumetric flask and stirred with 45 mL methanol on a magnetic stirrer for 15 minutes. The solution was filtered and diluted up to 50 mL with methanol. 2.5 mL of this solution and 1 mL internal standard solution were pipetted into 25 mL volumetric flask and completed with methanol up to the mark (sample solutions contain 10 mcg mL-1 felodipine and 2.56 mcg mL-1 hydrochlorthiazide). 20 µL volume of sample solution was injected into the column.



In this study, high performance liquid chromatography method was developed for the determinations of felodipine from agglomerates prepared by CCA technique. To find the appropriate RP-HPLC Conditions for determination of felodipine, various mobile phase systems were tested. The optimum wavelength for detection was 232 nm at which much better detector responses for active substance and internal standard were obtained. The mobile phase was chosen as methanol 0.055 M phosphate buffer (83:17 v/v- pH=3± 0.1). The mobile phase was found to be essential to improve the sharpness and thinness of the felodipine and hydrochlorthiazide (internal standard). The elution order were tr = 9.677 min for felodipine and tr = 3.317 min for internal standard at a flow rate of 0.8 mL min-1 (Table-1, Fig.-2). Linear relationship in the concentration range of 10-60 mcg mL-1 and the regression equation was obtained as y=0.146896x+0.091211 (r=0.99993). (Table 2)


Table 1. System suitability parameters for the estimation of Felodipine by using RP- HPLC method.

Sr. No.





Resolution (RS)



Retention Time in minutes (α)




Theoretical plates number (N)








Table 2. Statistical analysis of the results in the Estimation of Felodipine from agglomerates by using RP- HPLC method.



Range mcg /mL


Detection limit mcg /mL


Quantitation limit mcg /mL


Regression equation

Slope (a)

Intercept (b)




Correlation Coefficient (r)





The proposed developed method is practically applicable, simple, sensitive and rapid. This method could be used for routine analysis of agglomerates and commercial samples contacting Felodipine.



Authors are thankful to Glenmark pharmaceutical, Goa (India) and Cipla Pvt. Ltd. Goa (India) for providing the free gift samples of Felodipine and hydrochlorothiazide. Authors are thankful to Principal, Bharati Vidyapeeth College of pharmacy, Kolhapur for providing necessary facility.



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2)       United States Pharmacopoeial Convention. United States Pharmacopoeia. Rockville, MD: United States Pharmacopeia; 1975.

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5)       Lin K, Peck GE. Development of agglomerated talc. I. Evaluation of fluidized bed granulation parameters on the physical properties of agglomerated talc. Drug Dev Ind Pharm 1995; 21:159-173.

6)       Kachrimanis K., et al. Crystallisation conditions and physicomechanical properties of ibuprofen–Eudragit® S100 spherical crystal agglomerates, prepared by the solvent-change technique, International Journal of Pharmaceutics 1998; 173: 61–74.

7)       Kadam SS, et al. inventors. A process for making agglomerates for use as or in a drug delivery system. Indian Patent 183481. Feb.14, 1997.

8)       Patel YP, et al. Isocratic Simultaneous reversed-phase high performance liquid chromatographic estimation of six drugs for combined hypertension therapy, J. Chromatography A 1998; 828: 283-286.





Received on 23.07.2010        Modified on 02.08.2010

Accepted on 11.08.2010        © AJRC All right reserved

Asian J. Research Chem. 4(1):  January 2011; Page 88-90