The Utility of Lipids as Nanocarriers and Suitable Vehicle in Pharmaceutical Drug Delivery

Abstract

Lipid based excipients have gained popularity recently in the formulation of drugs in order to improve their pharmacokinetic profiles. For drugs belonging to the Biopharmaceutics Classification System (BCS) class II and IV, lipid excipients play vital roles in improving their pharmacokinetics properties. Various nanocarriers viz: Solid lipid nanoparticles, nanostructured lipid carriers, selfnanoemulsifying drug delivery systems (SNEDDS), nanoliposomes and liquid crystal nanoparticles have been employed as delivery systems for such drugs with evident successes. Lipid-based nanotechnology have been used to control the release of drugs and have utility for drug targeting and hence, have been used for the delivery of various anticancer drugs and for colon targeting. Drugs encapsulated in lipids have enhanced stability due to the protection they enjoy in the lipid core of these nanoformulations. However, lipid excipients could be influenced by factors which could affect the physicochemical properties of lipid-based drug delivery systems (LBDDS). These factors include the liquid crystalline phase transition, lipid crystallization and polymorphism amongst others. However, some of the physicochemical properties of lipids made them useful as nanocarriers in the formulation of various nanoformulations. Lipids form vesicles of bilayer which have been used to deliver drugs and are often referred to as liposomes and nanoliposomes. This work aims at reviewing the different classes of lipid excipients used in formulating LBDDS and nanoformulations. Also, some factors that influence the properties of lipids, different polymorphic forms in lipid excipients that made them effective nanocarriers in nano-drug delivery would be discussed. Special considerations in selecting lipid excipients used in formulating various forms of nanoformulations would be discussed.