Introduction: The blood–brain barrier (BBB) represents a stringent barrier for delivery of neurotherapeutics in vivo. An attempt to overcome this barrier is represented by the direct transport of drugs from the nose to the brain along the olfactory and trigeminal nerve pathways. These nerve pathways initiate in the nasal cavity at olfactory neuroepithelium and terminate in the brain. An enormous range of neurotherapeutics, both macromolecules and low molecular weight drugs, can be delivered to the central nervous system (CNS) via this route. Areas covered: Present review highlights the literature on the anatomy-physiology of the nasal cavity, pathways and mechanisms of neurotherapeutic transport across nasal epithelium and their biofate and various strategies to enhance direct nose to brain drug delivery. The authors also emphasize a variety of drug molecules and carrier systems delivered via this route for treating CNS disorders. Patents related to direct nose to brain drug delivery systems have also been listed. Expert opinion: Direct nose to brain drug delivery system is a practical, safe, non-invasive and convenient form of formulation strategy and could be viewed as an excellent alternative approach to conventional dosage forms. Existence of a direct transport route from the nasal cavity to the brain, bypassing the BBB, would offer an exciting mode of delivering neurotherapeutic agents.

In the era of nanoparticulate controlled and site specific drug delivery systems, use of solid lipids to produce first generation lipid nanoparticles, solid lipid nanoparticles (SLN), became a revolutionary approach in the early nineties. The present review is designed to provide an insight into how SLN are finding a niche as promising nanovectors and forms a sound basis to troubleshoot the existing problems associated with traditional systems. Herein, authors had tried to highlight the frontline aspects prominent to SLN. An updated list of lipids, advanced forms of SLN, methods of preparation, characterization parameters, and various routes of administration of SLN are explored in-depth. Stability, toxicity, stealthing, targeting efficiency and other prospectives of SLN are also discussed in detail. The present discussion embodies the potential of SLN, now being looked up by various research groups around the world for their utility in the core areas of pharmaceutical sciences, thereby urging pharmaceutical industries to foster their scale-up.

The polyelectrolyte complexes (PECs) are versatile formulations formed by electrostatic interactions between oppositely charged biopolymers. PECs have been investigated widely by the researchers to explore the virtues of this formulation viz. high biocompatibility, excellent biodegradability, low toxicity, cost-effective, environment-friendly, and energy-efficient production. The prime object of the present review is to present the prominent features of PECs including mechanism of PEC formation, structural models of PECs, interactions involved in PEC formation, steps involved in PEC fabrication, factors affecting the formation of PECs and applications of PECs. The patents pertaining to PECs have briefly been tabulated as well.