Preparation and study of vitamin A palmitate microemulsion drug delivery system and investigation of co-surfactant effect

The oral route is the main route of drug delivery in many diseases. a major problem in oral oil-soluble drug administration is poor aqueous solubility. one way to deliver oil-soluble drugs is to incorporate the drug into an inert vehicle, such as microemulsions. the purpose of this research was to develop the oil-in-water (o/w) microemulsion areas of pseudo-ternary phase diagrams for a drug delivery system. our systems consist of sunflower oil + surfactant (tween 80) + vitamin a palmitate + different co-surfactants + water. vitamin a palmitate is an oil-soluble drug with poor aqueous solubility. our goal is to increase its aqueous solubility. the effects of different co-surfactants on the o/w microemulsion region were investigated. the co-surfactants studied were anhydrous glycerol, sucrose, ethanol, and 1-propranol. a titration technique was employed for the preparation of the samples. the phases were identified by visual inspection and polarized microscopy. samples of the microemulsion area were separated, and pseudo-ternary phase diagram was plotted for them. the system sunflower oil + tween 80 + sucrose + water+ model drug showed the largest o/w microemulsion region. consequently, sucrose was selected as the best co-surfactant. finally, some samples of this system were selected for particle size measurement and stability testing. results showed that more than 90% of the samples in different temperatures (4°c, 45°c, and room temperature) are stable.