Quantification of Linagliptin by Chemical Derivatization with Appliance of Chromogenic Reagents


Gokaraju Rangaraju College of Pharmacy, Osmania University, Hyderabad, Telangana, India


Two simple, specific, accurate, precise, sensitive and cost effective
spectrophotometric methods have been developed and validated for quantification of
linagliptin in pure form and pharmaceutical formulations. Method A is established on
the computation of absorbance of purple coloured chromogen complex at 463 nm
which is formed by the condensation reaction of the primary amine group of
linagliptin with vanillin (Schiff base formation). Method B is established on
computation of absorbance of orange coloured chromogen at 454 nm which is formed
by the condensation reaction of the primary amino group of linagliptin with NQS
(1,2-naphtho quinine 4- sulphonic acid sodium salt) reagent. Two methods executed
linearity in the concentration range of 2.5-20 µg/ml and 10-90 µg/ml for method A
and B respectively. Linear relationship with good correlation coefficients of 0.998 and
0.995 were monitored between absorbance and corresponding concentrations of
linagliptin in vanillin and NQS respectively. The limit of detection, limit of
quantification, molar absorptivity, sandell’s sensitivity and ring born concentration values were determined for the two spectrophotometric methods. The contemplated
methods were validated statistically as per ICH guidelines. The reliability of both the
methods is further ascertained by performing recovery tests by standard addition
method. No significant interference was inspected from the excipients commonly
used as pharmaceutical aids with the assay procedure. The contemplated methods
were simple, sensitive, specific and can be successfully employed in routine analysis
of linagliptin in pharmaceutical dosage forms.