Stability of Pharmaceutical formulations are oftenly challenged by compatibility between drugs and excipients. The objective of the present study is to identify compatibility between drug:drug and drugs:excipient. Curcumin and Tretinoin were selected as model drug where Ethyl cellulose (EC) and Poly vinyl alcohol (PVA) as excipients. The study was done by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction study (XRD) and Thin layer chromatography (TLC). The spectrophotometric graphs revealed that there was no significant changes in position of functional groups of Curcumin, Tretinoin, EC and PVA (O-H, C=O, C-H str.) in pure drugs and excipients with respect to their physical mixtures. X-ray diffraction study reflects that the characteristic peaks of curcumin appeared at a diffraction angle of 2Ã?â??Ã?± at 7.950, 8.800, 12.280, 17.290 showing that Curcumin and Tretinoin was present as a crystalline form as well. The Rf values of the physical mixtures obtained from TLC study on the 0th and 30th day were approximately similar to the Rf values of the pure Curcumin and Tretinoin. The above spectrophotometric data and retention factor clearly implies that the synthetic-herbal drug combinations with pharmaceutical excipients are compatible with each other and can be introduced for successful development of novel drug delivery system.
