
Poor aqueous solubility, hepatic first-pass metabolism, presence of barriers and enzymes might be hamper the oral absorption of the majority of new chemical entities. Solid lipid nanoparticles (SLNs) can be an attractive for oral drug delivery vehicle as they grip tremendous possible to improve the oral bioavailability of drugs, associated reduction of drug toxicity and stability of drug in both GIT and plasma. SLNs are in submicron size range and are made of biocompatible and biodegradable materials capable of incorporating both lipophilic and hydrophilic drugs. SLNs are also considered as substitute to other colloidal drug systems and also used controlled systems and targeted delivery. This review provides the summary on the development of SLNs of poorly water soluble drugs for improved oral delivery. Further, special focus will be made on the current status of pharmacokinetic and pharmacodynamic studies reported on SLNs.