Controlled Release Drug Delivery Systems: An Overview
Abstract
Background: The field of controlled drug delivery has seen significant advancements over the past six decades, evolving through three distinct generations (1G, 2G, and 3G) with var-ying degrees of success. The primary aim of this review is to assess the progress and challenges in drug delivery systems, particularly focusing on nanoparticle formulations and their ef-ficacy in clinical applications. Aims: This review aims to evaluate the development and impact of nanoparticle-based drug delivery systems, examine their presumed unique properties, and identify the barriers that have hindered their clinical success. Methodology: The review analyzes the evolution of drug delivery technologies from the 1950s to the present, examining first-generation (1G) oral and transdermal systems, second-gen-eration (2G) nanotechnology-based systems, and the emerging
third-generation (3G) systems. It explores the mechanisms of drug release, pharmacokinetic (PK) profiles, and the biological barriers encountered in different drug delivery approaches. The analysis includes a critical examination of the literature on nan-oparticle formulations, their development, testing, and clinical translation. Results: The findings indicate that while 1G systems were highly successful due to predictable PK profiles and robust en-gineering principles, 2G systems faced significant challenges due to biological unpredictability. Nanoparticle formulations, despite their potential for targeted drug delivery, have shown
only marginal improvements in drug accumulation at target sites and have not resulted in significant clinical breakthroughs. Conclusion: The review concludes that future success in drug delivery requires innovative approaches to overcome both formulation and biological barriers. Researchers must critically reassess the assumptions surrounding nanotechnology and ex-plore new methodologies to achieve substantial improvements in drug delivery efficacy and patient outcomes. This evolution emphasizes the need for continued research, open-mindedness, and a departure from conventional paradigms.