Spectrophotometric Methods for the Determination of Anti-diabetic Drug Glipizide in Pure and Pharmaceutical Formulations

Abstract

Four simple and precise spectrophotometric methods were developed and optimized for
the assay of glipizide (GPZ) in pure form and in its pharmaceutical preparations. Method A
was based on the reaction of drug with 1,2-naphthoquinone-4-sulfonate (NQS) in alkaline
medium to form orange colored product (λmax 456 nm). In the method B, drug reduced the
reagent tetrazolium blue (TB) which lead to the formation of intense violet colored
formazan (λmax 515 nm). The method C employed Folin-Ciocalteu reagent (FC) that reacted
with drug in alkaline medium to form blue colored complex (λmax 760 nm). Method D was
based on the reduction of iron(III) to iron(II) by the drug and their complexation with
bathophenanthroline (BPT) to form pink colored complex (λmax 547 nm). Linearity of Beer’s
plots was observed in the concentration range of 10.00 – 100.00 µg mL-1
, 2.00 – 22.00 µg
mL-1
, 5.00 – 40.00 µg mL-1
, 0.50 – 7.50 µg mL-1
for method A, B, C and D respectively. The
proposed methods were validated and values of analytical parameters like molar
absorptivity, Sandell’s sensitivity, limits of detection and quantification were also calculated.
The methods were found to be selective for the quantitative determination of GPZ in
commercially available formulations.