Available online at www.derpharmachemica.com Scholars Research Library Der Pharma Chemica, 2011, 3(1): 144-155 (http://derpharmachemica.com/archive.html) ISSN 0975-413X CODEN (USA): PCHHAX 144 www.scholarsresearchlibrary.com Thermal and dissolution studies of Cefpodoxime proxetil drug and tablets Sanjiv Arora, Prabjot Kaur and Mahender Kumar Department of Chemistry, Kurukshetra University, Kurukshetra, India ______________________________________________________________________________ ABSTRACT Cefpodoxime proxetil is commonly used antibacterial drug. Thermal analysis and dissolution studies are routinely conducted by pharmaceutical industries in order to evaluate the drug stability, the drug- excipient interaction and compatibility. In this study dynamic thermogravimetry (TG) experiments were performed in flowing dry air atmosphere (20 ml min -1 ) to investigate the thermal decomposition of cefpodoxime proxetil drug and tablets (A, B and C) containing different excipients. The TG curve of cefpodoxime proxetil drug shows single decomposition process while tablets (A, B and C) display two. Decomposition activation energies and thermal rate constant (k T ) were determined using model-free methods viz. Kissinger, Friedman, Flynn-Wall-Ozawa, and modified Coats-Redfern. The dissolution study of samples was carried out in accordance of United State Pharmacopeia (USP 32) and Kitazawa equation was used for kinetics. Samples are found to have following sequence of the thermal stability: tablet B < cefpodoxime proxetil drug < tablet A < tablet C and the dissolution order: tablet B < cefpodoxime proxetil drug < tablet A < tablet C. The thermal rate constant (k T ) and dissolution rate constant (k D ) were also correlated graphically and found to have very good correlation with regression coefficient close to 1. Key words: Cefpodoxime proxetil, kinetics, TG and dissolution. Nomenclature: A pre-exponential factor or frequency factor, (min -1 ) E activation energy of degradation reaction, (kJ mol -1 ) n order of reaction R universal gas constant, (J K -1 mol -1 ) t time, (s -1 ) T absolute temperature, (K) T m temperature value at the maxima of the first derivative weight loss curve k T thermal rate constant k D dissolution rate constant TG thermogravimetry DTG derivative thermogravimetry DTA differential thermal analysis