Effect of Extragranular Microcrystalline Cellulose on Compaction, Surface Roughness, and In Vitro Dissolution of a Self-Nanoemulsified Solid Dosage Form of Ubiquinone

portant component of the mitochondrial respiratory chain (1). Because of its poor aqueous solubility, Coenzyme Q10 (CoQ10) presents a challenge when developing a formulation for oral administration. Many approaches have been used to improve the in vitro dissolution of CoQ10. Some of the approaches include complexation with cyclodextrins (2), preparation of redispersible dry emulsion (3), solid dispersion (4), and recently, development of a eutectic-based self-nanoemulsified drug delivery system (5). Self-emulsifying drug delivery systems (SEDDS) are isotropic mixtures of oil, surfactant, cosurfactant, and drug that form a fine oil-in-water emulsion when introduced into an aqueous medium during gentle agitation (6,7). SEDDS-based formulations, however, require filling into soft or hard gelatin capsules. It was therefore of interest to incorporate the self-emulsifying vehicles into a powder to produce solid dosage forms. Recently, pellets containing a self-emulsifying mixture were prepared by extrusion–spheronization (8). Solidstate microemulsion for the delivery of cyclosporin also was prepared by coating the premicroemulsion with an enteric material (9). Similarly, a solvent-evaporation method was used to prepare tocopheryl nicotinate tablets using calcium silicates as the adsorbing agent (10). Such methods often require elaborate processing and instrumentation. On the other hand, Jarowski (11,12) and later Spireas (13– 15), produced solid solutions and liquisolids by blending liquid medications with selected powder excipients to produce free-flowing, readily compressible powders. Such excipients include cellulose or lactose as the carriers and fine silicates as the coating material. Using a similar approach, Akzo Nobel (16) and Cima Labs (17) introduced a solid dosage form based on microemulsion adsorbed onto colloidal silicon dioxide and microcrystalline cellulose. In most cases as well as in the case of liquisolids, however, adsorbed oilor lipid-based formulations form a thin film of oil on the surface of the powder. This film causes particles to adhere and produces a mass that exhibits poor flow and tableting characteristics (13). To improve