A comparative evaluation of mono-, di- and triglyceride of medium chain fatty acids by lipid/surfactant/water phase diagram, solubility determination and dispersion testing for application in pharmaceutical dosage form development.

Purpose: To compare physiochemical properties of mono-, di- and triglycerides of medium chain fatty acids for development of oral pharmaceutical dosage forms of poorly water-soluble drugs using phase diagrams, drug solubility, and drug dispersion experiments.

Methods: Phase diagrams were prepared using a monoglyceride (glycerol monocaprylocaprate: Capmul MCM® EP), a diglyceride (glycerol dicaprylate) and two triglycerides (glycerol tricaprylate: Captex 8000®; caprylic/capric triglycerides: Captex 355 EP/NF®) in combination with a common surfactant (PEG-35 castor oil: Cremophor EL®) and water. Psuedoternary phase diagrams using mixtures of monoglyceride with either diglyceride or triglyceride were constructed to determine any potential advantage of using lipid mixtures.

Result: The monoglyceride gave microemulsion (clear or translucent liquid) and emulsion phases, whereas di- and triglycerides exhibited an additional gel phase. Among individual mono-, di- and triglycerides, the oil-in-water microemulsion region was the largest for the diglyceride. Gel phase region within diglyceride and triglyceride phase diagrams could be practically eliminated and microemulsion regions expanded by mixing monoglyceride with di- or tri-glycerides (1:1). Addition of a model drug, danazol, had no effect on particle sizes of microemulsions formed. Dispersion of drug in aqueous media from mixtures of mono- and diglyceride or mono- and triglyceride was superior to individual lipids.

Conclusion: Systematic study on comparison of mono-, di- and triglyceride of medium chain fatty acids will help formulators select components for optimal lipid-based formulation.