Self-emulsifying drug delivery systems (SEDDS) of coenzyme Q10: formulation development and bioavailability assessment.

The goals of our investigations are to develop and characterize self-emulsifying drug delivery systems (SEDDS) of coenzyme Q10 (CoQ10), using polyglycolyzed glycerides (PGG) as emulsifiers and to evaluate their bioavailability in dogs. Solubility of CoQ10 was determined in various oils and surfactants. SEDDS consisted of oil, a surfactant and a cosurfactant. Four types of self-emulsifying formulations were prepared using two oils (Myvacet 9-45 and Captex-200), two emulsifiers (Labrafac CM-10 and Labrasol) and a cosurfactant (lauroglycol). In all the formulations, the level of CoQ10 was fixed at 5.66% w/w of the vehicle. The in vitro self-emulsification properties and droplet size analysis of these formulations upon their addition to water under mild agitation conditions were studied. Pseudo-ternary phase diagrams were constructed identifying the efficient self-emulsification region. From these studies, an optimized formulation was selected and its bioavailability was compared with a powder formulation in dogs. Medium chain oils and Myvacet 9-45 provided higher solubility than long chain oils. Efficient and better self-emulsification processes were observed for the systems containing Labrafac CM-10 than formulations containing Labrasol. Addition of a cosurfactant improved the spontaneity of self-emulsification. From these studies, an optimized formulation consisting of Myvacet 9-45 (40%), Labrasol (50%) and lauroglycol (10%) was selected for its bioavailability assessment. A two-fold increase in the bioavailability was observed for the self-emulsifying system compared to a powder formulation. SEDDS have improved the bioavailability of CoQ10 significantly. The data suggest the potential use of SEDDS to provide an efficient way of improving oral absorption of lipophilic drugs.