Spectrophotometric evaluationof methyldopa in pure and pharmaceutical formulation using Ecological-friendly Method

Abstract

Abstract Asimple, low cost, precise and fast spectrophotometric methods development for estimation of methyldopa are described. The primary method which includes conversion of methyldopa to colored complex with Fe (II) in the alkaline medium (PH=12). The colored product has a violet color with absorbance at λmax 555 nm. Between the concentration range (5-50 μg⋅mL−1), the Beer s law is obeyed with correlation coefficient (R2= 0.9994), limit of detection as 0.1641 μg⋅mL−1, limit of quantification as 0.541 μg⋅mL−1 and molar absorptivity as 1562.22 L⋅mol−1⋅cm−1. The other technique, cloud point extraction was utilized to determination of a trace amount of the colored product in the previous method followed by measuring with a UV-Vis spectrophotometer. The linearity of calibration curvewas above the range of (1-50 μg⋅mL−1), the correlation coefficient (R2= 0.9991) and molar absorptivity was 6080 L⋅mol−1⋅cm−1. The detection limit(LOD) and quantification limit(LOQ) were based to be 0.0486 and 0.160 μg⋅mL−1 respectively. This technique was successfully employed for methyldopa detection within the pure and pharmaceuticalpreparations.