Emulsions of hydrolyzable oils for the zero-order release of hydrophobic drugs

Drug delivery systems that release hydrophobic drugs with zero-order kinetics remain rare and are often complicated to use. In this work, we present a gellified emulsion (emulgel) that comprises oil droplets of a hydrolyzable oil entrapped in a hydrogel. In the oil, we incorporate various hydrophobic drugs and, because the oil hydrolyzes with zero-order kinetics, the release of the drugs is also linear. We tune the release period from three hours to 50 h by varying the initial oil concentration. We show that the release rate is tunable by varying the initial drug concentration. Our quantitative understanding of the system allows for predicting the drug release kinetics once the drug's partition coefficient between the oil and the aqueous phase is known. Finally, we show that our drug delivery system is fully functional after storing it at -20 degrees C. Cell viability studies show that the hydrolyzable oil and its hydrolysis product are non-toxic under the employed conditions. With its simplicity and versatility, our system is a promising platform for the zero-order release of the drug.

Automated summary

This study introduces a drug delivery system using a gellified emulsion for zero-order release of hydrophobic drugs, demonstrating tunable release rate and period by varying initial oil and drug concentrations. The system's quantitative understanding allows for predicting drug release kinetics, and it remains fully functional even after storing at -20 degrees C. Cell viability studies confirm the non-toxicity of the hydrolyzable oil and its hydrolysis product under the utilized conditions.