Abstract

SPECTROPHOTOMETRIC DETERMINATION AND CLOUD POINT EXTRACTION OF LAMOTRIGINE DRUG IN PURE FORM AND PHARMACEUTICAL PREPARATION

Saadiyah Ahmed Dhahir*, Shatha Mahdi

ABSTRACT

A new, simple and sensitive of two spectrophotometric methods for the determination of Lamotrigine drug has been developed. First method is based on diazotization of O-aminobenzoic acid, by sodium nitrite in acidic medium at 5Cº followed by coupling with Lamotrigine in alkaline media to yield orange coloured products with absorption maxima at 424 nm. Beer’s law is obeyed from 0.5–18 μg mL–1 with r=0.9997 Sandell’s sensitivity were 0.0888 μg∙cm-2, molar absorptivity (ε) 2.88×103 L.mol-1.cm-1,The limits of quantification 0.149 μg mL–1 and limits of detection were 0.110 μg mL–1. Intraday precision (RSD 1.62– 3.04%) and accuracy (recovery 97–100.25%) of the developed method were evaluated. No interference was observed. The Second method by cloud point extraction in aqueous media the product of diazotization coupling of O-aminobenzoic acid, with Lamotrigine process using non-ionic surfactant (TritonX-114) at 60 °C, further determination spectrophotometric of trace Lamotrigine compounds from water samples was investigated using extracted surfactant-rich phase and diluted with ethanol and its absorbance was measured at 424 nm. The effect of different variables such as temperature, Triton X-114 volume and time. Under optimal conditions, the calibration graph was linear in the range of 0.5-23 μg mL–1 of CPE with r=0.9999 Sandell’s sensitivity were 0.0864 μgcm-2 . Average recoveries for samples were determined to be between 97.33–100.17 %. The relative standard deviation (RSD 1.50– 3.01%) of CPE and detection limit was 0.103 μg mL–1, limits of quantification 0.121 μg mL–1 molar absorptivity (ε) 2.96×103 L.mol-1.cm-1 in surfactant-rich phase. The two methods have been successfully applied to the assay of Lamotrigine drug in pharmaceutical formulations.

Keywords: Lamotrigine drugs, O-aminobenzoic acid, diazotization, spectrophotometry, pharmaceutical formulation.