Factors affecting the efficiency of a self-emulsifying oral delivery system

Dosage forms containing a self-emulsifying system have shown significant promise in improving the in vitro dissolution rate and oral absorption of lipophilic drugs. In such a system, a surfactant, or a surfactant plus medium chain monoglyceride (co-emulsifier), is added to a lipophilic vehicle (oil) containing dissolved drug. In the present study, surfactants with different hydrophile-lipophile balance (HLB), fatty acid glycerides (co-emulsifiers) with varying fatty acid (C-8-C-18) chain length, and lipophilic vehicles (oils) containing different fatty acid (C-8-C-18) compositions were evaluated for their effectiveness in producing self-emulsifying systems. This investigation showed that the HLB of the surfactant, as well as the fatty acid chain length of the monoglyceride have a significant effect on the performance of the self-emulsifying system; a surfactant with an HLB in the range of 10-15 and a monoglyceride of medium chain fatty acid (C-8-C-10) were most effective. Also, there ape certain critical concentrations of surfactant and monoglyceride necessary for preparing an optimum self-emulsifying oral drug delivery system.