Development and Characterization of Solid Self-emulsifying Drug Delivery System of Cilnidipine

The present investigations highlight the development of solid self-emulsifying drug delivery system (solid-SEDDS) for improved oral delivery of the poorly water-soluble drug; cilnidipine. Liquid SEDDS of the drug were formulated using Capryol 90 as the oil phase, Tween 80 as the surfactant, and Transcutol HP as the co-surfactant after screening various vehicles. The prepared systems were characterized for self-emulsification time, robustness to dilution, % transmittance, globule size, drug release, and thermodynamic stability. Ternary phase diagrams were plotted to identify the area of microemulsification. The optimized liquid SEDDS was transformed into a free-flowing powder using Neusilin US2 as the adsorbent. Solid self-emulsifying powder retained the self-emulsifying property of the liquid SEDDS. Differential scanning calorimetric, X-ray powder diffraction studies revealed the possibility of transformation of the crystalline form of the drug to the amorphous form in the SEDDS prepared with the carrier. The morphology of solid-SEDDS from scanning electron microscopy studies demonstrated the presence of spherical, granular particles indicating good flowing ability. Dissolution studies revealed enhanced dissolution of the drug from the solid system compared with the pure drug and its marketed formulation. Similarly, the in vitro absorption profile of the drug from the formulated SEDDS was significantly higher compared with pure drug. Thus it can be concluded that solid-SEDDS, amenable for development of solid dosage form, can be successfully developed using Neusilin US2 with the potential of enhancing the solubility, dissolution rate, and bioavailability of the drug.