Determination of linagliptin and empagliflozin by UPLC and HPTLC techniques aided by lean six sigma approach.

Two chromatographic techniques were developed and validated for simultaneous determination of the newly co-formulated antidiabetic combination linagliptin and empagliflozin in their pure form and film-coated tables. The first technique was UPLC; the separation and resolution of both analytes were achieved using a Zorbax eclipse plus C column applying an isocratic elution based on phosphate buffer pH 4-acetonitrile (65:35, v/v) as a running mobile phase at flow rate 1.5 ml/min and the effluent was monitored at 220 nm. Augmentation of Lean Six Sigma with UPLC and HPTLC methods had a major impact on the development of robust specifications to ensure that the quality at six sigma level has a high level of statistical confidence and target performance. On the chromatogram, empagliflozin and linagliptin appeared at retention times of 1.417 and 2.453 min, respectively. The second technique was HPTLC; both analytes were fairly well resolved and separated using a developing mobile phase composed of ethyl acetate-chloroform-acetonitrile (55:25:20 by volume). The values of retention factor (R ) were 0.29 and 0.53 for linagliptin and empagliflozin, respectively. All variables were investigated to adjust the whole conditions.