Solid Lipid Nanoparticles: A Potential Approach for Drug Delivery System

The therapeutic efficacy of perorally administered drug is often concealed by their poor oral bioavailability (BA) and low metabolic stability in the gastrointestinal tract (GIT). Most of the newly discovered drug molecules are of high molecular weight and belong to biopharmaceutical classification system (BCS) – II. Poor aqueous solubility and high membrane permeability characteristics of BCS – II drugs limit BA after oral administration. Recently, lipid-based drug delivery (LBDD) systems have gained much importance due to their ability to improve the solubility and BA of poorly soluble drugs. Oral delivery of drugs incorporated in solid lipid nanoparticles (SLNs) has gained considerable interest since the last two decades. SLNs have advantages above the others, as compared to polymer toxicity which is low, as inexpensive excipients and organic solvents are not used. SLNs offer the possibility to develop new therapeutics due to their unique size-dependent properties. An attempt to incorporate drugs into SLNs offers a new prototype in drug delivery system which can be utilized for drug targeting to specific tissue. This review presents elaborate information of SLNs with their aim, advantages, challenges and limitations, the principle of formulation, routes of administration and their biodistribution. It also describes the gastrointestinal absorption and the factors affecting absorption of SLNs from GIT along with its application.