Cloud Point Extraction and Spectrophotometric Determination of Codeine in Pharmaceutical and Biological Samples

Cloud point extraction process using non-ionic surfactant, Triton X-114, to extract codeine from aqueous solution was investigated. The method was based on the extraction of codeine and bromothymol blue from acetate buffer media to surfactantrich phase and formed a charge transfer-ion pair complex. The extracted surfactant-rich phase was diluted with ethanol and its absorbance was measured at 430 nm. The effect of different variables such as pH, Triton X-114 concentration, cloud point temperature and time was established. The calibration graph was linear in a wide range of 100-700 ng ml-1 of codeine with r = 0.998 (n = 7). The detection limit based on three times standard deviation of the blank (3s) was 4.6 ng ml-1 and relative standard deviation (R.S.D) is 2.15% for 500 ng ml-1 codeine (n = 5). The proposed method was applied to the determination of codeine in acetaminophen codeine tablets and blood samples