The article provides an updated review of drug delivery systems, focusing on nasal and pulmonary routes, which are gaining importance for treating human diseases. Various drug delivery systems, such as liposomes, proliposomes, microspheres, gels, prodrugs, cyclodextrins, and nanoparticles, are discussed for their potential in these routes. Nanoparticles made from biodegradable polymers are highlighted for their ability to meet stringent requirements, including aerosolization, stability, biocompatibility, targeted delivery, and controlled release. The article also covers the development of targeted drug delivery systems for brain, lung, and infectious diseases, as well as strategies for intraventricular/intrathecal and transdermal delivery. Additionally, it explores the use of colloidal drug carriers like micelles and liposomes, and the potential of nanotechnology in enhancing drug delivery to the brain. The article concludes by discussing the advantages and challenges of colon-specific drug delivery systems and the need for further clinical studies to validate the efficacy of these systems.The article provides an updated review of drug delivery systems, focusing on nasal and pulmonary routes, which are gaining importance for treating human diseases. Various drug delivery systems, such as liposomes, proliposomes, microspheres, gels, prodrugs, cyclodextrins, and nanoparticles, are discussed for their potential in these routes. Nanoparticles made from biodegradable polymers are highlighted for their ability to meet stringent requirements, including aerosolization, stability, biocompatibility, targeted delivery, and controlled release. The article also covers the development of targeted drug delivery systems for brain, lung, and infectious diseases, as well as strategies for intraventricular/intrathecal and transdermal delivery. Additionally, it explores the use of colloidal drug carriers like micelles and liposomes, and the potential of nanotechnology in enhancing drug delivery to the brain. The article concludes by discussing the advantages and challenges of colon-specific drug delivery systems and the need for further clinical studies to validate the efficacy of these systems.