Facile Colorimetric
Determination of Duloxetine in Formulations Using Methyl
Orange as Ion-Pairing Agent
Pushparaj Hemalatha1,2,
Mani Ganesh1,2, Mei Mei Peng1,2
and Hyun Tae Jang1,2*
1Department of Chemical
Engineering, Hanseo University, 2Korea Carbon
Capture & Sequestration R&D Centre, 360 Daegok-ri,
Haemi-myun, Seosan-si 356 706, Chungcheongnam-do, South
Korea
*For correspondence: Email:
htjang@hanseo.ac.kr
Tel.: +82-41-660-1423
Received: 30 April
2012
Revised accepted:
27 December
2012
Tropical
Journal of Pharmaceutical Research, February 2013;
12(1): 93-97
http://dx.doi.org/10.4314/tjpr.v12i1.15
Abstract
Purpose:
To develop a new and
fully validated ion-pair spectrophotometric method for
the determination of duloxetine hydrochloride (DX).
Methods: Ion-pair spectrophotometric
method was employed for the determination of duloxetine
hydrochloride (DX) in bulk and pharmaceutical
formulations using acidic dye methyl orange (MO) as
ion-pairing agent at pH 4 (phthalate buffer). The yellow
ion-pair complex was extracted with chloroform and
spectrophotometrically estimated at 420 nm. The
developed method was validated according to ICH and USP
guidelines.
Results: The ion-pair complex of DX
and MO obeyed Beer’s law in the range of 2 - 20 μg mL-1
of DX with a correlation coefficient of 0.998.
Recovery was good, with a relative standard deviation (%RSD)
of 0.88 - 1.02; precision (inter-day, 0.878 and
intra-day, 0.921) was also within validation limits. The
limit of detection (LOD) and limit of quantitation (LOQ)
were 0.25 and 4 μg mL-1, respectively. The
method developed was successfully applied to determine
DX in a formulation.
Conclusion:
The developed method is
accurate, precise, rugged, robust and reproducible. It
is also sensitive and specific for the determination of
DX in bulk and formulation.
Keywords: Duloxetine, Methyl orange,
Ion-pair, Validation, Spectrophotometry.
