Lipid Nanoformulations for Oral Delivery of Bioactives: An Overview

Oral drug delivery has always been considered the preferred route of drug administration. Nano-formulations are now constantly being researched for better absorption, higher bioavailability and greater therapeutic efficacy. Lipid based nanoformulations have found much favour with the formulation scientist due to their relatively higher safety profile and enhancement of bioavailability. These delivery systems are also able to protect the bioactives or drugs from the vagaries of the gastrointestinal tract. They also aid in the absorption of hydrophobic drugs which are entrapped in lipid matrices. Lipid excipients have been known to reduce efflux which is P-glycoprotein mediated and also to increase the bioavailability of bioactives which are given through the oral route. In the last 20 years, about a thousand articles and reviews about oral lipid carriers have been reported. Many dosage forms have been made by modifying liposome, sometimes to overcome a disadvantage and at other times to modify the dosage form in such a manner so as to suit the requirement of the drug molecules. Various other lipidic drug delivery systems also exist which are not vesicular but being made of lipids, are equally useful for delivering lipophilic drugs. Although a Lipid Formulation Classification System exists, but there is no exhaustive review which discusses the entire lipid based, oral nanoformulations. The present review envisages discussing the various types of oral, lipid, nanosized, delivery systems available, so that an insight is gained into all these carriers, and the formulation scientist can make a judicious decision regarding choice of a lipid based carrier.