Effect of emulsion based drug delivery systems on rate of drug release and intestinal permeability enhancement

Emulsion based drug delivery systems have shown great promise for enhancing oral bioavailability yet have not been widely commercially utilized, largely due to lack of mechanistic understanding of their function. Major functional properties of emulsion-based drug delivery systems, permeability enhancement and drug release, were studied and statistically related to a broad range of formulation properties through Analysis of Variance (ANOVA) and regression analysis. Three surfactants with a high, medium and low Hydrophilic Lipophilic Balance (HLB) value and three structurally different oils (long chain triglyceride, medium chain triglyceride and propylene glycol dicaprylate/dicaprate) were combined at three oil to surfactant ratios. Heterogeneous formulations of low HLB (HLB=10) surfactant had a toxic effect on cells at high (>50%) surfactant concentrations, which may be an indication of importance of formulation stability for decreasing toxicity. Electrical resistance indicated that high HLB surfactant, Tween 80, loosens tight junction at high (>50%) surfactant concentrations. Release coefficients from each emulsion system were calculated. Incorporation of long chain triglyceride, Soybean oil, as the oil phase altered rate of release from oil droplets whereas high surfactant demonstrated a retarding effect.