A New Stability-Indicating HPLC Method for Simultaneous Determination of Curcumin and Celecoxib at Single Wavelength: an Application to Nanoparticulate Formulation

It is a well known fact curcumin; a coloring principle in turmeric has emerged as the most exploited phyto-constituents for its wide spectrum of biological activities. Mostly, it is available in the market as a mixture of three different constituents, commonly known as curcuminoids. These curcuminoids constitute majorly 75% curcumin (curcumin I), followed by 20% desmethoxycurcumin (curcumin II) and to smaller extent bisdesmethoxycurcumin (curcumin III, 5%) (Figure 1) [1]. Research over the last two decades has shown curcumin to be a potent antioxidant, anti-inflammatory, anti-proliferative, anti-metastatic, anti-angiogenic, anti-diabetic, hepatoprotective, antiatherosclerotic, anti-thrombotic, and anti-arthritic agent [2]. Structurally, curcumin is 1,7-bis (4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione, desmethoxycurcumin is 1,6-Heptadiene-3,5-dione,1-(4-hydroxy-3methoxyphenyl)-7-(4-hydroxyphenyl) and bisdesmethoxycurcumin is 1,7-bis (4-hydroxyphenyl) hepta-1,6-diene-3,5-dione (Figure 1) [1,3]. These three molecules show very small chemical modifications with respect to their number of methoxy groups (none for bisdesmethoxycurcumin, one for desmethoxycurcumin and two for curcumin) and the presence of methoxy groups in the ortho position on the aromatic ring, [4]. However, these modifications influence the hydrophobic nature of three curcuminoids which is in the order of curcumin > desmethoxycurcumin > bisdesmethoxycurcumin, with curcumin being the relatively most hydrophobic among the three curcuminoids.