Application of Ion Selective Electrode for Determination of Lamivudine in Pure Form, Drug Product, Plasma and in presence of its Related Impurities

The field of Electro-chemical sensors development is now highly grown for the determination of traces amounts of drugs. A novel polyvinylchloride membrane sensor for the determination of lamivudine is prepared and characterized. The sensor is based on the use of the ion association complex of lamivudine anion with iron(II)-phenanthroline counter cation as an ion exchange site in the polyvinylchloride matrix. The performance characteristics of this sensor was evaluated according to IUPAC recommendations, which reveal a fast, stable and linear response for lamivudine over the concentration range of 10-6 to 10-2 mol L-1 for the sensor with anionic slope of 27.3 mV per concentration decade for the sensor. The direct potentiometric determination of lamivudine using the proposed sensor gave recovery of 99.57±0.62% for the sensor. The proposed sensor displayed useful analytical characteristics for the determination of lamivudine in bulk powder, pharmaceutical formulations, and biological fluids (plasma) and in the presence of some related impurities, namely cytosine, uracil and salicylic acid. Validation of the method shows suitability of the proposed sensor for the use in quality control assessment of lamivudine. The developed method was found to be simple, accurate and precise when compared with an official high performance liquid chromatographic method. Also the method allows direct determination of lamivudine without pretreatment or separation steps in turbid or colored solutions in presence of some related impurities