Novel approach for overcoming the stability challenges of lipid-based excipients. Part 3: Application of polyglycerol esters of fatty acids for the next generation of solid lipid nanoparticles

Abstract

Solid lipid nanoparticles (SLN) are an advantageous carrier system for the delivery of lipophilic active pharmaceutical ingredients (APIs). The use of SLN has been limited due to stability issues attributed to the unstable solid state of the lipid matrix. A novel approach for overcoming this problem is the application of polyglycerol esters of fatty acids (PGFAs) as lipid matrices with stable solid state. PG2-C18 full, a PGFA molecule, was used to develop SLN loaded with dexamethasone as a model API. Dexamethasone-loaded SLN were manufactured via melt-emulsification and high pressure homogenization in the dosage form of a lipid nanosuspension. SLN with median particle size of 242.1 ± 12.4 nm, zeta potential of −28.5 ± 7.8 mV, entrapment efficiency of 90.2 ± 0.7% and API released after 24 h of 81.7 ± 0.7%, were produced. Differential Scanning Calorimetry (DSC) and Small and Wide Angle X-Ray Scattering (SWAXS) analysis of the lipid nanosuspension evidenced the crystallization of PG2-C18 full in a monophasic system in α-form and absence of polymorphism and crystallite growth up to 6 months storage at room temperature. This resulted in stable performance of the SLN after storage: absence of particle agglomeration, no API expulsion, and stable release profile. The potential pulmonary administration of SLN was tested by the nebulization capacity of the lipid nanosuspension. Cellular exposures to SLN did not induce cytotoxicity or immune effect on pulmonary cells. The application of PGFAs as safe and stable lipid matrices provide a promising approach for the development of the next generation of SLN.