Nanostructured lipid carrier (NLC) is second generation smarter drug carrier system having solid matrix at room temperature. This carrier system is made up of physiological, biodegradable and biocompatible lipid materials and surfactants and is accepted by regulatory authorities for application in different drug delivery systems. The availability of many products in the market in short span of time reveals the success story of this delivery system. Since the introduction of the first product, around 30 NLC preparations are commercially available. NLC exhibit superior advantages over other colloidal carriers viz., nanoemulsions, polymeric nanoparticles, liposomes, SLN etc. and thus, have been explored to more extent in pharmaceutical technology. The whole set of unique advantages such as enhanced drug loading capacity, prevention of drug expulsion, leads to more flexibility for modulation of drug release and makes NLC versatile delivery system for various routes of administration. The present review gives insights on the definitions and characterization of NLC as colloidal carriers including the production techniques and suitable formulations. This review paper also highlights the importance of NLC in pharmaceutical applications for the various routes of drug delivery viz., topical, oral, pulmonary, ocular and parenteral administration and its future perspective as a pharmaceutical carrier.

Now a day's intranasal (i.n) drug delivery is emerging as a reliable method to bypass the blood-brain barrier (BBB) and deliver a wide range of therapeutic agents including both small and large molecules, growth factors, viral vectors and even stem cells to the brain and has shown therapeutic effects in both animals and humans. This route involves the olfactory or trigeminal nerve systems which initiate in the brain and terminate in the nasal cavity at the olfactory neuroepithelium or respiratory epithelium. They are the only externally exposed portions of the central nervous system (CNS) and therefore represent the most direct method of noninvasive entry into the brain. This approach has been primarily used to explore therapeutic avenues for neurological diseases. The potential for treatment possibilities with olfactory transfer of drugs will increase as more effective formulations and delivery devices are developed. Recently, the apomorphine hydrochloride dry powders have been developed for i.n. delivery (Apomorphine nasal, Lyonase technology, Britannia Pharmaceuticals, Surrey, UK). The results of clinical trial Phase III suggested that the prepared formulation had clinical effect equivalent to subcutaneously administered apomorphine. In coming years, intranasal delivery of drugs will demand more complex and automated delivery devices to ensure accurate and repeatable dosing. Thus, new efforts are needed to make this noninvasive route of delivery more efficient and popular, and it is also predicted that in future a range of intranasal products will be used in diagnosis as well as treatment of CNS diseases. This review will embark the existing evidence of nose-to-brain transport. It also provides insights into the most relevant pre-clinical studies of direct nose-brain delivery and delivery devices which will provide relative success of intranasal delivery system. We have, herein, outlined the relevant aspects of CNS drugs given intranasally to direct the brain in treating CNS disorders like Alzheimer's disease, depression, migraine, schizophrenia, etc.