Spectrophotometric method development and validation for simultaneous estimation of Anagliptin and Metformin HCl BY Q - Absorption ratio method in synthetic mixture

A simple, accurate, precise and economical Q- Absorption Ratio spectrophotometric method was developed and validated for estimation of Anagliptin and Metformin HCl in synthetic mixture. Anagliptin and Metformin HCl showed an iso-absorptive point at 238 nm in distilled water. The second wavelength used was 233 nm which is λ(max) of Metformin HCl in distilled water. The concentration of the drugs was determined by using ratio of absorbance at iso-absorptive point (λ(1) = 238 nm) and at the λ(max) of Metformin HCl (λ(2) = 233 nm). This method is linear for both drugs; in range of 2–12 μg/mL at λ(1) (R(2) = 0.999) and at λ(2) (R(2) = 0.9998) for Anagliptin, and in the range of 5–30 μg/mL for Metformin HCl found at λ(1) (R(2) = 0.9995) and at λ(2) (R(2) = 0.9997). The % Recovery was 100.42–101.83 % of Anagliptin and 99.94–101.63 % of Metformin HCl by standard addition method. The LOD was found to be 0.201 μg/mL and 0.262 μg/mL for Anagliptin at λ(1) and λ(2) respectively. The LOD was found to be 0.320 μg/mL and 0.167 μg/mL for Metformin HCl at λ(1) and λ(2) respectively. The LOQ was found to be 0.610 μg/mL and 0.794 μg/mL for Anagliptin at λ(1) and λ(2) respectively. The LOQ was found to be 0.972 μg/mL and 0.506 μg/mL for Metformin HCl at λ(1) and λ(2) respectively. The method was found to be precise as % RSD was less than 2.00 in Repeatability, Interday and Intraday precision for Anagliptin and Metformin HCl. The % assay of analyte drugs in synthetic mixture was found to be 100.601% of Anagliptin and 100.206 % of Metformin HCl which showed good applicability of the developed method.