Background: The aim of the study was to evaluate the suitability of triclosan (TCS) and flurbiprofen (FLB) with poly-ε-caprolactone (PCL), chitosan (CS), and Kolliphor® P188 (KP) for possible application in the design of nano-formulations.Results: Differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM) revealed the physical characteristics of the various sample compositions without any apparent interaction. The Fourier transform infrared spectroscopy (FTIR)’s spectra of the physical mixtures showed their characteristic absorption bands with broadening and overlapping of bands in some instances, but no appearance of new bands was observed.Conclusion: The study revealed the physical form stability of the evaluated components after the storage period and lack of definite pharmaceutical incompatibility between them. Thus, the selected drugs and excipients could be used for the development of pharmaceutical nano-formulations.

A simple, economic, rapid, reliable, and stability-indicating high-performance liquid chromatography (HPLC) method has been developed and validated for the simultaneous determination of paracetamol (PCM) and caffeine (CF) in solid dosage form. The chromatographic separations were achieved with a Waters Symmetry® C18 column (5 μm, 4.6 × 150 mm), using a mixture of methanol and water (40:60, v/v) as a mobile phase, under isocratic elution mode with a flow rate of 0.8 mL/min, and ultraviolet (UV) detection was set at 264 nm. The oven temperature for the column was set and maintained at 35 °C. The method was validated according to International Conference on Harmonization (ICH) guidelines, and it demonstrated excellent linearity, with a correlation coefficient of 1 and 0.9999 for PCM and CF, respectively, over the concentration ranges of 15–300 μg/mL (PCM) and 2.5–50 μg/mL (CF). The retention time (t_R) was found to be 2.6 ± 0.001 and 3.5 ± 0.002 min for PCM and CF, respectively. Extensive stress degradation studies were conducted by subjecting the analytes to various stress conditions of acidic and alkaline hydrolysis as well as oxidative, photolytic, and heat degradations. The method was found to efficiently separate the analytes' peaks from that of the degradation products, without any variation in their retention times. The relative standard deviation (RSD) values of all recoveries for PCM and CF were less than 1.3%. The method was found to be suitable for routine analysis of PCM and CF in pharmaceutical dosage form.