Background: Linagliptin (LNG) is an oral hypoglycemic agent that acts by inhibiting
the enzyme dipeptidyl peptidase - 4 (DPP-4) and reduces blood sugar levels in type-II diabetic patients.
To date, the literature presents few analytical methods for the determination of LNG. However,
no reversed phase-high performance liquid chromatography (RP-HPLC) method has been reported
for the determination of LNG in nanotransfersomes and in vitro skin permeation samples.
Objective: The present study involves the development and validation of RP-HPLC method to
quantify LNG in both nanotransfersomes and in vitro skin permeation and deposition samples.
Methods: The chromatographic analysis was performed on Luna C18 (2) column (250 x 4.6 mm,
5μm particle size) with a mobile phase consisting of a mixture of methanol: 0.2% orthophosphoric
acid (50:50, v/v) at a flow rate of 1.0 mL/min, detection wavelength of 227 nm, and column temperature
of 40 °C.
Results: The method was found to be specific, linear (r2 ≥ 0.999; 2-12 μg/mL), precise at both
intra and inter-day levels (percentage relative standard deviation; % RSD < 2.00), accurate (percentage
recovery 100.21-103.83%), and robust. The detection and quantification limits were 0.27
and 0.82 μg/mL, respectively. The mean % entrapment efficiency and the cumulative amount of
LNG permeated across the rat skin from different transfersomal formulations ranged between
40.78 ± 2.54 % to 52.26 ± 2.15 % and 79.54 ± 16.67 to 200.74 ± 35.13 μg/cm2 respectively.
Conclusion: The method was successfully applied to determine the entrapment efficiency, in vitro
skin permeation and deposition behavior of LNG-nanotransfersomes.