en Evaluation of Celecoxib-Lactose Incompatibility Reactions at Solid State using Physicochemical Methods تخصصي Special پژوهشي orginal article <strong><em>Background & Aims</em></strong>: &nbsp;Drug excipient incompatibility evaluation is an important part of pre-formulation studies. Drug-excipient interaction may affect drug stability, bioavailability, therapeutic effects, efficacy, and safety. Therefore, development of a successful drug delivery systems or dosage forms depends on correct selection of excipients. The aim of this study is to evaluate of celecoxib-lactose incompatibility reactions at solid state using physicochemical methods.<br> <strong><em>Materials & Methods:</em></strong> Celecoxib and lactose were blended in 1:1 mass ratios and added to 20% (v/w) water and stored in closed vials at 60&deg;C (inside the oven). Also, pure drug and pure excipient were prepared. Celecoxib, celecoxib-lactose and lactose tablets prepared using direct compression method. Produced tablets were stored at 60 &deg;C (inside the oven). Finally, celecoxib -lactose incompatibility in the solid state was investigated by Fourier transform infrared (FTIR) and differential scanning calorimetry (DSC) methods over four consecutive weeks.<br> <strong><em>Results</em></strong><strong>:</strong> the incompatibility of celecoxib with lactose was not observed using physicochemical methods including DSC, FTIR spectroscopy and also visual observation.<br> <strong><em>Conclusion:</em></strong> It can be concluded that using lactose in celecoxib solid pharmaceutical preparations will not cause incompatibilities. Incompatibility, Excipient, Celecoxib, Lactose 139 146 http://ijrabms.umsu.ac.ir/browse.php?a_code=A-10-90-2&slc_lang=en&sid=1 Ali Fattahzadeh ali.fattahzadeh247@gmail.com 10031947532846001239 10031947532846001239 No School of pharmacy, Urmia University of Medical Sciences, Urmia, Iran Azin Jahangiri jahangiri.az@gmail.com 10031947532846001240 10031947532846001240 No Department of pharmaceutics, School of Pharmacy, Urmia University of Medical Sciences, Urmia, Iran Naser Ranjkeshzadeh n.ranjkeshzadeh@yahoo.cim 10031947532846001241 10031947532846001241 No School of pharmacy, Urmia University of Medical Sciences, Urmia, Iran Faranak Ghaderi f.ghaderi1390@gmail.com 10031947532846001242 10031947532846001242 Yes Department of Pharmaceutical and Food Control, School of Pharmacy, Urmia University of Medical Sciences, Urmia, Iran,research center for experimental and applied pharmaceutical Sciences