Application of Stability Indicating HPTLC Method for Quantitative Determination of Escitalopram Oxalate in Pharmaceutical Dosage Form

Abstract

A sensitive, selective, precise and stability indicating high-performance thin-layer
chromatographic method of analysis of escitalopram oxalate both as a bulk drug and in
formulations was developed and validated. The method employed TLC aluminium plates
precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of
toluene: acetone: ethanol: ammonia (5:1:1:0.2 v/v/v/v). This system was found to give compact
spots for escitalopram oxalate (Rf value of 0.50Ä0.02). Escitalopram oxalate was subjected to
acid and alkali hydrolysis, oxidation, dry heat treatment and photodegradation. Also the peaks
of degraded products were well resolved from the pure drug with significantly different Rf values.
Densitometric analysis of escitalopram oxalate was carried out in the absorbance mode at 239
nm. The linear regression analysis data for the calibration plots showed good linear relationship
with concentration range of 200–1200 ng.spot-1
. The mean value of correlation coefficient, slope
and intercept were 0.9987Ä0.236, 4.186 Ä1.53 and 594.8 Ä0.856, respectively. The method was
validated for precision, robustness and recovery. The limits of detection and quantitation were
20 and 50 ng.spot-1
, respectively. Statistical analysis proves that the method is repeatable and
selective for the estimation of the said drug. As the method could effectively separate the drug
from its degradation products, it can be employed as a stability indicating one.