Hydration of triglyceride oils caused a significant decrease in the solubility of steroids, which may form hydrates or hemihydrates. Results suggest the need for knowledge of the hydration state of triglyceride oils to be used as pharmaceutical excipients.

In systems nearly saturated with drug, the microemulsion formulation leads to a greatly enhanced rate of steady-state mass transport while in systems with drug loading far from saturation, the microemulsion formulation appears to have a minimal ability to promote mass transport. The aqueous boundary layer diffusion model was successful in fitting progesterone results but was not successful for estradiol.