Innovative UV Protocols Based on Straightforward Mathematical Filtration for Concurrent Estimation of Two Antidiabetic Drugs in Their Brand-New Combination: A Comparative Study.

Background: In 2019, the U.S. Food and Drug Administration approved a brand-new combination of linagliptin and empagliflozin in a formulation called Glyxambi® tablets for managing type 2 diabetes mellitus. Nowadays, spectrophotometric techniques occupy the first place among their peers in terms of ease of application, friendliness to the environment, and low costs.

Objective: This research discusses the development of two very simple spectrophotometric protocols based on zero-order spectra for the determination of linagliptin and empagliflozin.

Methods: The developed protocols were the induced dual-wavelength and absorption correction protocols. Linagliptin could be determined directly at 305 nm, at which the empagliflozin spectrum was zero-crossing. Empagliflozin was determined using the two developed protocols. The induced dual-wavelength technique was developed by calculating the equality factor of linagliptin to cancel its interference. The absorption correction technique was developed by measuring the correction absorption factor.

Results: The concentration ranges of linagliptin and empagliflozin were 1-10 µg/mL and 3-30 µg/mL, respectively. Excellent recovery results were found in bulk, dosage form, and synthetic mixtures. Low LOD and LOQ values were obtained, indicating the high sensitivity of the protocols. The statistical Student's t-test was performed to compare the results of the applied and reported protocols, indicating no difference between them.

Conclusion: The proposed protocols have the advantages of being straightforward, affordable, and requiring no sophisticated manipulations, just simple mathematical calculations. The proposed protocols are acceptable for routine usage in QC laboratories and in future research applications.

Highlights: Two novel univariate methods were developed for quantitative analysis of linagliptin and empagliflozin in their pharmaceutical and laboratory mixtures, and produced satisfactory results.