Effect of binary solid lipid matrix of wax and triglyceride on lipid crystallinity, drug-lipid interaction and drug release of ibuprofen-loaded solid lipid nanoparticles (SLN) for dermal delivery.

HYPOTHESIS: The physicochemical properties of solid lipid nanoparticles (SLN) depend on lipid compositions. An addition of secondary solid complex triglycerides (Softisan 378; S378) into solid wax (cetyl palmitate; CP) is expected to influence the properties of obtained SLN compared to SLN prepared from sole CP.

EXPERIMENTS: Ibuprofen-loaded SLN (IBSLN-TG) composed of different ratios of CP and S378 were prepared and evaluated in term of size, zeta potential (ZP), entrapment efficiency (E.E.), crystallinity, lipid-drug interaction and in vitro drug release.

FINDINGS: After production, all developed IBSLN-TG prepared from different ratios of CP and S378 had the particle size in the nanometer range (180-200nm) with the ZP values of higher than |-40mV| and possessed approximately 100% E.E. The release of IBSLN-TG demonstrated the biphasic pattern with a fast release followed by sustained release, which was fitted to Higuchi's kinetics. The addition of S378 into CP-matrix led to a slight decrease in particle size and surface charge, and distortion of CP crystallization. The results from 1 H-NMR indicated the formation of tiny liquid S378 nanocompartments within CP-matrix. The localization of ibuprofen in the S378 nanocompartments and the interaction between ibuprofen and S378 had an impact on the release profiles of IBSLN-TG depending on the ratios of CP and S378.