The purpose of this review is to provide an insight into the different aspects of pH-sensitive liposomes. The review consists of 6 parts: the first introduces different types of medications made in liposomal drug delivery to overcome several drawbacks; the second elaborates the development of pH-sensitive liposomes; the third explains diverse mechanisms associated with the endocytosis and the cytosolic delivery of the drugs through pH-sensitive liposomes; the fourth describes the role and importance of pHsensitive lipid dioleoylphosphatidylethanolamine (DOPE) and research carried on it; the fifth explains successful strategies used so far using the mechanism of pH sensitivity for fusogenic activity; the final part is a compilation of research that has played a significant role in emphasizing the success of pH-sensitive liposomes as an efficient drug delivery system in the treatment of malignant tumours. pH-Sensitive liposomes have been extensively studied in recent years as an amicable alternative to conventional liposomes in effectively targeting and accumulating anti-cancer drugs in tumours. This research suggests that pH-sensitive liposomes are more efficient in delivering anti-cancer drugs than conventional and long-circulating liposomes due to their fusogenic property. Research focused on the clinical and therapeutic side of pH-sensitive liposomes would enable their commercial utility in cancer treatment.

The purpose of this report was to compile relevant technical information on various alternative strategies that can be used as feasible approaches in the development of solid dispersions. The technologies discussed in the report are spray coating on sugar beads with a fluidized bed coating system, hot melt extrusion, direct capsule filling, electrostatic spinning, surface active carriers, and supercritical fluid technology. The focus is on basic principles, the equipment involved, and the relevant scale-up work. These technologies have been found to eliminate several drawbacks posed by the conventional methods of manufacturing of solid dispersions such as laborious preparation methods, reproducibility, scaling up of manufacturing processes, stability of drug, and vehicle.

Nanotechnology offers a vision for a ‘smart’ drug approach involving the design, synthesis, and characterization of materials and devices that have a functional association in nanometer scale. One area in which nanotechnology may have a significant clinical impact in neuroscience is the selective transport and delivery of drugs and other small molecules across the strictest barrier in vivo, the blood brain barrier (BBB). Therefore, various strategies have been proposed to improve the delivery of different antineoplastic drugs, oligonucleotides, genes, and magnetic resonance imaging contrast agents to this tissue. This review deals in brief about the status of the BBB, different pathologies of brain like neurodegenerative, cerebrovascular and inflammatory diseases. The first part of this article aims to review the strategies developed to circumvent the BBB and deliver drugs into the brain. The use of nanotechnology and advancements are discussed especially in the crucial part of the review manifesting their potentiality as non-invasive technique which overcomes the blood-brain barrier limiting characteristics in the delivery of drugs with the possibility to target specific brain tissue decreasing peripheral toxicity.