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.