Encapsulation of alpha-Pinene in Delivery Systems Based on Liposomes and Cyclodextrins

The essential oil component alpha-pinene has multiple biological activities. However, its application is limited owing to its volatility, low aqueous solubility, and chemical instability. For the aim of improving its physicochemical properties, alpha-pinene was encapsulated in conventional liposomes (CLs) and drug-in-cyclodextrin-in-liposomes (DCLs). Hydroxypropyl-beta-cyclodextrin/alpha-pinene (HP-beta-CD/alpha-pinene) inclusion complexes were prepared in aqueous solution, and the optimal solubilization of alpha-pinene occurred at HP-beta-CD:alpha-pinene molar ratio of 7.5:1. The ethanol-injection method was applied to produce different formulations using saturated (Phospholipon 90H) or unsaturated (Lipoid S100) phospholipids in combination with cholesterol. The size, the phospholipid and cholesterol incorporation rates, the encapsulation efficiency (EE), and the loading rate (LR) of alpha-pinene were determined, and the storage stability of liposomes was assessed. The results showed that alpha-pinene was efficiently entrapped in CLs and DCLs with high EE values. Moreover, Lipoid S100 CLs displayed the highest LR (22.9 & PLUSMN; 2.2%) of alpha-pinene compared to the other formulations. Both carrier systems HP-beta-CD/alpha-pinene inclusion complex and Lipoid S100 CLs presented a gradual release of alpha-pinene. Furthermore, the DPPH radical scavenging activity of alpha-pinene was maintained upon encapsulation in Lipoid S100 CLs. Finally, it was found that all formulations were stable after three months of storage at 4 & DEG;C.