A Review on Simultaneous Estimation of Atenolol and Indapamide by UV Spectrophotometric Methods

Namra Momin, Zoha Khan, Sahil Khan, Mariyam Maniyar, Kanchan Khandekar, Aarti Khemkar, Ushda Khan,

doi:10.5281/zenodo.18330426

Review Paper | Open Access
Volume 04 | Issue 01 | Article Id IJPS/260401146

A Review on Simultaneous Estimation of Atenolol and Indapamide by UV Spectrophotometric Methods
Namra Momin* Zoha Khan Sahil Khan Mariyam Maniyar Kanchan Khandekar Aarti Khemkar Ushda Khan
Shri Pandit Baburao Chaughule College of Pharmacy, Bhiwandi 421302 , Maharashtra, India.

Abstract

The combination of Atenolol, a ??-selective adrenergic blocker, and Indapamide, a thiazide-like diuretic, is widely prescribed for hypertension management. Reliable analytical procedures are required for simultaneous quantification of these drugs in combined dosage forms. UV-visible spectrophotometry is an economical alternative to chromatographic techniques owing to its simplicity, rapid operation and minimal solvent consumption. This review summarizes UV-spectrophotometric approaches used for the concurrent estimation of Atenolol and Indapamide, including the simultaneous equation method, absorbance-ratio (Q-analysis), dual-wavelength technique and derivative/ratio-spectra methods. Key analytical considerations such as wavelength selection, solvent choice and validation parameters in accordance with ICH Q2(R1) guidelines are highlighted. Most reported methods demonstrate acceptable linearity, accuracy and precision; however, robustness and specificity assessments are often limited. Comparative evaluation indicates that the simultaneous equation and dual-wavelength approaches provide effective quantification when spectral overlap is addressed appropriately. UV spectrophotometry remains a practical and cost-effective tool for routine quality control of Atenolol–Indapamide formulations.

Keywords

Atenolol, Indapamide, UV-spectrophotometry, Simultaneous estimation, Method validation, ICH guidelines

Introduction

Hypertension remains one of the most prevalent cardiovascular disorders worldwide. Fixed-dose drug combinations are widely used to enhance therapeutic efficacy and patient compliance. Atenolol, a cardioselective β?-blocker, reduces heart rate and myocardial oxygen demand, while Indapamide, a thiazide-like diuretic, promotes natriuresis and vasodilation. Their combined therapeutic action is beneficial in the long-term control of blood pressure. Quality assessment of fixed-dose combinations requires analytical procedures capable of simultaneously quantifying both drugs without prior separation. Although chromatographic techniques such as RP-HPLC are highly sensitive and selective, they involve significant operational costs and long analysis time. UV-visible spectrophotometry has gained popularity as a simple and cost-effective alternative for routine quality control analysis.The major analytical challenge is the overlapping UV absorption spectra of Atenolol and Indapamide. Several mathematical and wavelength-based approaches have been developed to overcome this limitation.This review discusses these methods and compares their analytical performance.^.[3,4,5]

SPECTROSCOPY METHODS:

Simultaneous Equation Method^[1,2,3,7]:

This method uses two selected wavelengths near the λmax values of the drugs. Absorbances of the mixture are measured at both wavelengths, and simultaneous linear equations incorporating individual absorptivity values are solved. The method is simple and provides good accuracy when λmax values are sufficiently distinct.

Absorbance Ratio (Q-analysis) Method^[1,2,4]:

This method utilizes an isoabsorptive point where both drugs have identical absorptivity along with the λmax of one component. Q-values computed from absorbance measurements are substituted into equations to determine concentrations. The method reduces problems associated with overlapping spectra.

Dual-Wavelength Method^[3,6,7]:

Two wavelengths are selected where the absorbance difference for one drug is insignificant, while the second drug shows a measurable difference. This eliminates the interference of one component, improving selectivity.

Derivative and Ratio-Spectra Methods^[8,9,10,11]:

Derivative spectrophotometry and ratio-spectra manipulation improve spectral resolution by highlighting small differences in overlapping bands. These approaches are useful when conventional methods provide inadequate specificity.

Practical experimental factors^[2,3,4,5]:

Solvent systems: Methanol, water, and methanol–water mixtures.
Wavelength range: Typically scanned between 200–400 nm.
Cuvettes: 1 cm quartz cuvettes.
Linearity: Often 10–80 μg/mL for Atenolol and 2–20 μg/mL for Indapamide.

VALIDATION PARAMETERS (as per ICH Q2(R1))^{[1,2,3,4,5,9,10,12]}:

Linearity:

Most reported methods show correlation coefficients ≥ 0.998.

Accuracy:

Recovery studies at 80%, 100% and 120% levels typically fall within 98–101%.

Precision:

Intra-day and inter-day %RSD values are generally < 2%, indicating acceptable repeatability.

Limit of Detection (LOD) & Limit of Quantification (LOQ):

Values differ by method but remain adequate for tablet-strength quantification.

Specificity and Robustness:

While specificity for simple formulations is acceptable, robustness testing is limited in many studies.

DISCUSSION / COMPARATIVE ANALYSIS^[1-13]:

UV spectrophotometric methods are widely used for simultaneous estimation of Atenolol and Indapamide due to their operational simplicity and minimal cost. The simultaneous equation and Q-analysis methods are commonly applied and provide accurate results under optimized conditions. The dual-wavelength technique offers enhanced selectivity by eliminating interference. Derivative and ratio-spectra approaches further improve resolution when spectral overlap is significant.

Table 1. Summary of Reported UV Spectrophotometric Methods for Simultaneous Estimation of Atenolol and Indapamide.

Sr No	Authors	Method	Isoabsorptive Points (nm) /λmax	Solvent / Diluent	Linearity range (μg/ml)	% recovery range	% RSD (precision)
1.	Pal et al.	Simultaneous Estimation and Q analysis	AT 274 nm; IND 240nm ;iso 261 nm	Methanol: Water (50:50)	AT 10-70, IND 2-20	98.5-101%	<1.5%
2.	Tarkase et al.	Simultaneous equation	AT 274nm; IN 240nm	Methanol	0;IN 5-25	99.2-100.8%	<2%
3.	Fernandes et al.	Dual Wavelength + Simultaneous Equation	226 & 246 nm (for A 241 & 259 nm (for IN	Methanol + Water (1:1)	AT 10-50; IN 2-10	98.7-100.6%	<2%
4.	Baheti et al.	Ion-Pair RP-HPLC (Comparative Method)	UV Detection at 235	Phosphate buffer pH 3.0+ Methanol	AT 5-60; IN 1-20	99.1-100.3%	<1%
5.	Rani et al.	RP-HPLC (Validation Comparison)	235 nm	Methanol: Buffer (70:30)	AT 10-100; IN 2-20	99.5-100.5%	<1%
6.	Francis & Kurup	UV Simultaneous Equation (Amlodipine-Indapamide )	238 nm & 260 nm	Methanol	5-25	98-100%	< 1.5%
7.	Patil et al.	Review on Analytical Methods for Indapamide	Various (240-260 ??	-	-	-	-
8.	Gupta et al.	HPTLC (Comparison Method	235 nm (Detection)	Methanol: Ethyl acetate system	AT 10-80; IN 2-20	98-100%	<2%
9.	Pai et al.	UV Spectrophotometric Single-Drug (Indapamide)	240 nm	Methanol	2-20	99-101%	<2%
10.	Kalyankar et al.	lon-Pair LC (Indapamide + Amlodipine)	238 nm	Phosphate buffer: Acetonitrile (60:40)	2-20	99-100%	<1%

Validation completeness: Many reported UV methods show acceptable linearity, recovery and precision, but fewer studies include comprehensive robustness testing (e.g., deliberate small pH/solvent changes), forced degradation specificity, or cross-brand transfer studies. For regulatory acceptance or method transfer, these aspects should be strengthened.

CONCLUSION:

UV spectrophotometric techniques provide practical and reliable methods for simultaneous estimation of Atenolol and Indapamide in pharmaceutical formulations. When properly optimized, these methods show good linearity, precision and accuracy. Nonetheless, comprehensive robustness and specificity studies are recommended for improved regulatory acceptance. UV spectrophotometry remains an effective and economical choice for routine analysis in quality control laboratories.^{[1-5,8,12,15]}

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