UV Spectrophotometric Method for the estimation of Azilsartan
Medoxomil in Bulk Form
Gawai M. N.1, Surwade K. S.2, Phadatare
D. G.3
KCT’S RGS Institute of Pharmacy, Anjaneri, Nashik,
422213, Maharastra, India
*Corresponding Author E-mail:
It is simple, sensitive and highly accurate
ultraviolet spectrophotometry method has been developed and validated for the
determination of Azilsartan medoxomil. It is approved by USFDA for the
treatment of hypertension. It is an angiotensin II receptor antagonist. This
method is based on the measurement of absorbance of Azilsartan medoxomil
solution in Phosphate buffer pH7.8 at 249 nm in the wavelength range 200-400
nm. Beers law was obeyed in concentration range 6- 16 µg/mL with coefficient of
0.9903. The percentage recovery of Azilsartan medoxomil range from 98.7253
to98.0887 %. Result of analysis is validated for linearity and range,
precision, recovery study, LOD and LOQ were found to be satisfactory.
KEYWORDS: Azilsartan
medoxomil, Phosphate buffer PH 7.8, spectrophotometry and validation.
INTRODUCTION:
Azilsartan medoxomil has chemical names (5
methyl-2-oxo-1,3-dioxol-4-yl) methyl-2-ethoxy-1-{[2’-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl}-1H-benzimidazole-7-carboxylate
monopotassium salt. It is rapidly hydrolysed to active moiety Azilsartan by
esterase in GIT and during the drug absorption. Azilsartan medoxomil Potassium
is practically insoluble in water and freely soluble in methanol.
Fig 1:Structure of Azilsartan Medoxomil
The absolute bioavailability of azilsartan medoxomil
is approximately 60%. The elimination half-life of azilsartan is approximately
11 hours and renal clearance is approximately
2.3 mL/min.
MATERIAL AND METHODS2,4 :
Material:
Azilsartan medoxomil working standard drug was
obtained from Hetro labs ltd, Hyderabad. All analytical grade chemicals and
solvents were supplied by S.D. Fine chemicals, Mumbai, India. Distilled water
was used to prepare all solution. Freshly prepared solution were always used.
Equipment:
The UV-spectrophotometry (Jasco V630) with data
processing system (UV Probe Software 2.31) was used. The sample solution was
recorded in 1cm quartz cell against solvent blank over the range 200-400 nm.
The citizen electronic balance (Schimadzu 220h) was used for weighing the
sample. An ultrasonicator bath (PCT Analytics Pvt. Ltd) was used for sonicating
the drug.
Method Development:
Preparation of Standard Stock Solution:
Accurately weighed 10 mg Azilsartan medoxomil in 100
mL phosphate buffer solution pH 7.8 was prepared to give a standard stock
solution of 100 µg/mL concentration.
Preparation of Calibration Curve
Figure 2 : Spectrum of Azilsartan medoxomil in phosphate buffer solution pH
7.8
From the standard stock solution fresh Aliquot of stock
solution was transferred into a series of volumetric flask and volume was made
up to the mark with phosphate buffer of pH 7.8 to produce the concentration
range 6-16 µg/mL. The resultant solution was scanned from 200 to 400 nm and the
spectrum was recorded to obtain the value of maximum wavelength. The
calibration graph of the absorbance verses the concentration of drug was
plotted and represented in figure 2.
Figure 3 : Calibration curve of Azilsartan medoxomil in
phosphate buffer solution pH7.8.at 249nm.
Method Validation3
The method was validated according to the (ICH)
guidelines.
Linearity and Range:
The response of the drug was found to be linear in the
investigation concentration range and the linear regression equation was y
=0.0553x+0.0081 with correlation coefficient 0.9903. The group with least value
for sum of squares of error i.e. 6-16 µg/mL was chosen as the best fit for
equation.
Precision:
Intraday and interday precision was determined by
measurement of the absorbance for three times on same day and on three
different days. The relative standard deviation for replicates of sample
solution was less than 2% which meet the acceptance criteria for established
method. The obtained results are presented in table 1.
Table 1: Results for Precision study
|
Concentration µg/Ml
|
Absorbance Mean
|
Standard Deviation
|
% Relative Standard Deviation
|
|
Intraday Precision(n=3)
|
|
80
|
0.4180
|
0.0054
|
1.3064
|
|
100
|
0.5410
|
0.0069
|
1.2835
|
|
120
|
0.6892
|
0.0006
|
0.0987
|
|
Interday Precision(n=3)
|
|
80
|
0.4543
|
0.0045
|
0.9990
|
|
100
|
0.5322
|
0.0072
|
1.3581
|
|
120
|
0.6713
|
0.0048
|
0.7245
|
Table 2 : Results for Accuracy study5
|
Sample
|
Amount of Standard Drug Added mg
|
Formulation
|
Total Mount Recovered mg
|
% Recovered
|
Standard Deviation
|
% Relative Standard Deviation
|
|
80
|
8
|
05
|
12.8342
|
98.7253
|
0.1446
|
1.1269
|
|
100
|
10
|
05
|
14.9196
|
99.4644
|
0.1052
|
0.7055
|
|
120
|
12
|
05
|
16.6750
|
98.0887
|
0.0932
|
0.5593
|
Accuracy study:
Recovery studies show that the developed method is
accurate as per ICH guidelines. Results for recovery study have been shown in
table 2.
LOD and LOQ:
The limit of detection (LOD) and limit of quantitation
(LOQ) of the drug were separately determine based on method of intercept and
the average value of slope using the following equation designated by ICH
guidelines
|
Sr. No.
|
Parameter
|
Data
|
|
1
|
λ –max
|
249
|
|
2
|
Beer’s law limit
|
6-16
µg/mL
|
|
3
|
Regression equation
|
Y = 0.0553x + 0.0081
|
|
4
|
Correlation coefficient
|
R2 = 0.9903
|
|
5
|
Slope
|
0.0553
|
|
6
|
Intercept
|
0.0081
|
|
7
|
Limit of detection
|
0.2627 µg/mL
|
|
8
|
Limit of quantitation
|
0.7962 µg/mL
|
RESULTS AND DISCUSSION:
Beer’s law is obeyed over the concentration range of
6-16µg/mL, using regression
analysis the linear equation y = 0.0553x + 0.0081 with a correlation
coefficient R2 =
0.9903.The limit of detection was found to be 0.2627 µg/mL and the limit of quantitation 0.7962 µg/mL.
Precision was calculated with intra and interday variation. Recovery study was
performed on formulation and % RSD was found. The optical parameter such as
Beer’s law limit, slope, and intercept value were calculated and given in
table 3. The method is validated for precision. The accuracy of method was
established by performing study in formulation. The result were given in table
2 and shows relative standard deviation was observed for analysis of three
samples indicate precision and reproducibility.
CONCLUSION:
The spectrophotometric method for the determination of
Azilsartan Medoxomil have been developed and validated as per ICH guidelines.
The developed method can be used for routine Quality Control analysis of
Azilsartan Medoxomil in pure drug.
REFERENCES:
1.
Azilsartan (Edarbi)
National Drug Monograph, PBM-MAP-VPE Drug Monograph, December 2011.
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Gorla R, Nagaraju CH,
Sreenivasulu B, Sreenivas N, KorupoluRb. New Simple UV Spectrophotometric
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3.
International Conference
on Harmonization Steering Committee. ICH Harmonized Tripartite Guideline-
Validation of Analytical Procedures: Text and Methodology ICH Q2 (R1); February
6, 2003.
4.
Pradeepthi J,
Masthanamma SK, Alekhya G, A Validated Spectrophotometric Method For Determination
of Azilsartan Medoxomil in Pharmaceutical Dosage Form, Journal of Science
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5.
ICH Harmonized
Tripartite Guideline, International Conference on Harmonization. Stability
testing of new drug substances and products Q1A
(R2) and Evaluation for stability data Q1E. Current step
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6. Alton’s Pharmaceutics: The Design and
Manufacturing of Medicines, Churchill Livingstone Elsevier. 3rd
edition, 2007: 322-538.
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Jayaraman, Inventor; Alembic
Research Centre, Vadodara, Applicant. Novel Polymorphs of Azilsartan Medoxomil
Potassium, PCT WO 2013/124748 A4, 2013 August 29.
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Zaiken K, Judy WM.
Azilsartan Medoxomil: A New Angiotensin Receptor Blocker, Clinical
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= the standard deviation of the response