Chemical Rapid Communications Vol.2 No.3, December 2014 ISSN: 2325-9892 (Print) 2325-9906 (Online) www.researchpub.org/journal/crc/crc.html 55 55 Abstract— Two new, simple and effective colorimetric methods were developed for determination of Imatinib (mesylate) in pure and pharmaceutical formulations. Charge transfer (CT) interactions between Imatinib as electron donor and 2,3-dichloro-5,6,-dicyano-p-benzo quinone (DDQ) and chloranilic acid (CAA) as π-electron acceptors. The obtained charge-transfer complexes were measured at λ max 462 nm and 537 nm for DDQ and CAA in methylene chloride, respectively. Different variables affecting the reaction were studied and optimized. Under the optimum conditions, Beer’s law was obeyed in the concentration range of the drug 0.25-3.50 mg/ 10 ml and 0.50-5.50 mg/ 10 ml upon using DDQ (0.4% w/v) and CAA (0.3% w/v), respectively, with correlation coefficients 0.996 and 0.998, respectively. The proposed methods showed good linearity, precision, reproducibility and the validity was assessed by applying the standard additions technique with mean percentage recovery 99.90 ± 1.36 in case of DDQ and 100.20 ± 0.91 in case of CAA. Keywords — Charge Transfer Complex, CAA , DDQ, Gleevec, Imatinib Mesylate, Spectrophotometry I. INTRODUCTION ANCER is the most common cause of mortality and morbidity in Egypt as well as in other countries as U.K. Despite recent advances in the treatments of cancer, the clinical outcome is yet far away from expectation. 1 Chronic Myelogenous Leukemia is a myeloproliferative disorder 2, 3 , that results from a malignant transformation of progenitor cells leading to clonal proliferation and accumulation of myeloid cells. CML is responsible for 15% of adult leukemias. 2 Imatinib mesylate methanesulphonic acid4-[(4-methylpip-erazin-1-yl) methyl]-N-[4-methyl-3- [(4-pyridin-3ylpyrim-idin-2-yl)amino]phenyl] benzamide, is a tyrosine kinase inhibitor 4 , that was found to be one of the most Submitted March 2014 Department of Pharmaceutical Chemistry , Faculty of Pharmacy and biotechnology, German University in Cairo, Egypt. Department of Chemistry, Faculty of Science, Cairo University, Giza, Egypt* *Correspondence to (e-mail:rasha.elnashar@guc.edu.eg) (Email: Ashraf.abadi@guc.edu.eg) recent medications used for the treatment of chronic myeloid leukemia and gastro-intestinal stromal tumor. The introduction of Imatinib mesylate, which targets the kinases presenting with these molecular alterations, has dramatically changed the management of these rare tumors, which were resistant to conventional cytotoxic chemotherapy, both in advanced and localized phases. 5 It has opened a new area in cancer therapy and is given orally and chronically, that is why it was chosen as a model drug. 6 It is also known as Signal Transduction Inhibitor 571 and as antineoplastic agent. Its target protein is produced by DNA translocation (Philadelphia chromosome), which leads to a fusion protein of Abl with Bcr termed Bcr-Abl. 7 Many methods were reported in literature for the determination of imatinib mesylate in bulk, dosage forms and biological fluids, although it is not official in any pharmacopeia some of these methods are HPLC/UV detection 8-10 , HPLC/Mass detection 11-13 , gas chromatography 14,15 , supercritical fluid chromatography 16 , capillary electrophoresis 17, 18 , voltammetric methods 19, 20 and spectrophotometric methods 21, 22 . However, no Spectrophotometric Colorimetric method using DDQ or CAA have been developed for the determination of imatinib mesylate as a bulk or pharmaceutical formulations. In this work, charge-transfer (CT) reactions are studied spectrophotometrically based on chromogen produced as a result of charge transfer complex formation of the drug with π-acceptors as chloranilic acid and DDQ developing certain colored products that are measured quantitatively. The aim of this work is to introduce a simple, precise and rapid procedure for the simultaneous quantitation of the cited drug in pure and pharmaceutical formulation. The proposed method is suitable for determination of the drug providing economic, less time consuming and more sensitive procedure compared with the reported spectrophotometric method (reference method) 21 , based on the formation of ion pair complex of imatinib with bromocresol green in acidic buffer followed by their extraction in chloroform. II. METHODS 2.1. Apparatus All absorption spectral measurements were made in the range of 400-800 nm using JASCO V-530 UV/VIS Spectrophotometer, made in Japan. 2.2. Materials and reagents Spectrophotometric Determination of Imatinib Mesylate using Charge Transfer Complexs in Pure Form and Pharmaceutical Formulation Shereen. E. Abdel Karim a , Raafat. A. Farghaly a , Rasha. M. El-Nashar a,b* , Ashraf. H. Abadi a * C