Magnetic polycaprolactone microspheres: drug encapsulation and control

Targeted drug delivery (TDD) systems have several advantages, especially with drugs having toxic side effects such as lornoxicam (LX) which shows high hepatotoxicity and nephrotoxicity, especially with long-term use. This work represents an attempt to control magnetic microspheres encapsulating LX and magnetite nanoparticles (MNPs) for potential targeted drug delivery of LX. Superparamagnetic nanoparticles were fabricated via the co-precipitation method and together with LX were encapsulated into polycaprolactone (PCL) microspheres through an oil-in-water (O/W) emulsion solvent evaporation method. The effects of changing the amount of drug, MNPs, and volume of the aqueous phase were investigated by preparing several microsphere formulations. Increasing the amount of encapsulated MNPs increased the magnetization of the microspheres without affecting the morphology. Doubling the volume of the aqueous phase resulted in a higher encapsulation efficiency and drug loading; 83.9% and 10.7%, respectively, while increasing the amount of drug had a negative effect on both drug loading and encapsulation efficiency. Drug release from the microspheres was successfully achieved and showed a biphasic nature. A system of four planar coils was then used to magnetically control the movement of a cluster of capsules in a glycerin medium, as a simulation for the targeting process. The microspheres were successfully controlled to move in a U-turn path with sharp corners demonstrating their potential for TDD applications.