Binary blend of glyceryl monooleate and glyceryl monostearate for magnetically induced thermo-responsive local drug delivery system

Purpose: To develop a novel monoglycerides-based thermal-sensitive drug delivery system, specifically for local intracavitary chemotherapy. Methods: Lipid matrices containing mixtures of glyceryl monooleate (GMO) and glyceryl monostearate (GMS) were evaluated for their potential application as magnetically induced thermo-responsive local drug delivery systems using a poorly water-soluble model drug, nifedipine (NF). Oleic acid-modified iron oxide (OA-Fe₃O₄) nanoparticles were embedded into the GMO-GMS matrix for remote activation of the drug release using an alternating magnetic field (AMF). Results: The crystallization behavior of binary blends of GMO and GMS as characterized by DSC did show temperature dependent phase transition. GMO-GMS (75:25 wt%) blend showed a melting (T _m ) and crystallization (T _c ) points at 42 C and 37 C, respectively indicating the potential of the matrix to act as an 'on-demand' drug release. The matrix released only 35% of the loaded drug slowly in 10 days at 37 C whereas 96% release was obtained at 42 C. A concentration of 0.5% OA-Fe₃O ₄ heated the matrix to 42.3 and 45.5 C within 5 min and 10 min of AMF exposure, respectively. Conclusions: The in vitro NF release profiles form the monoglycerides matrix containing 0.5% OA-Fe₃O₄ nanoparticles after AMF activation confirmed the thermo-responsive nature of the matrix that could provide pulsatile drug release 'on-demand'.