TITLE:
Determination of Lisinopril in Bulk and Pharmaceutical Formulations by Cloud Point Extraction—A Green Method
AUTHORS:
V. Mallikarjuna Sarma, N. V. S. Venugopal, L. Giribabu
KEYWORDS:
Lisinopril (LSP), Cobalt Thiocyanate (CTC), Coordination Complex Formation, Cloud Pint Extraction (CPE), Spectrophotometry
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.11 No.8,
August
14,
2020
ABSTRACT: A sensitive and eco-friendly method was developed
for the spectrophotometric determination of Lisinopril (LSP) in bulk and
pharmaceutical formulations by cloud point extraction technique. The method was
based on the formation of a blue-colored coordination complex between Lisinopril (LSP) and Cobalt Thiocyanate
(CTC) at a suitable pH. The
Complex in aqueous medium was extracted into
surfactant layer by cloud point extraction using a non-ionic surfactant
Triton X-114 and then the surfactant layer was dissolved in a suitable volume
of ethanol and the amount of Lisinopril was determined spectrophotometrically
at a wavelength of 625 nm. The conditions like
concentration of the drug, concentration of CTC and of Triton X-114, PH, etc. were optimized by
OFAT (One Factor At a Time) method. The linear range of calibration curve was 1 - 6 μg/ml and the linear regression equation with a
correlation coefficient of 0.99996 was y = 0.0021 + 0.084x. Preconcentration and
enrichment factors were found to be 100 and 3.12 respectively, achieving the
detection limit of 0.0588 μg/ml.
The proposed method was successfully applied for the determination of LSP in
the drug formulations. The obtained values were in agreement with the values as
quoted by the manufacturers.