eChapter Name: Regulatory Considerations for Liposomal Formulations
9789372190540
eBook Name: LIPOSOMAL DRUG DELIVERY: A NOVEL APPROACH FOR THERAPEUTICS
Introduction
The use of liposomes as carriers for drug delivery has had a profound impact on the pharmaceutical industry. In 1961, Alec Bangham made a significant contribution to the field by introducing liposomes, which sparked a wave of research and development in this area (Bangham, 1992). Over time, liposomes have become incredibly versatile in their ability to transport drugs, biomolecules, and gene therapies. This groundbreaking approach has not only enhanced the effectiveness of treatments but also minimized side effects by precisely targeting specific sites within the body (Lai et al., 2024). Liposomes are vesicular structures composed of one or more concentric lipid bilayers that enclose an aqueous core. Hydrophilic drugs are commonly found within the aqueous compartments, whereas hydrophobic drugs are incorporated into the lipid bilayers. The innovative design of this architecture enables flexible drug encapsulation and precise delivery to specific targets. Liposomes have a wide range of applications in medical science, going beyond drug delivery to encompass diagnostics and vaccines. This versatility greatly enhances their value in the field (Gupta et al., 2023).
An important milestone in liposomal delivery technology occurred in 1995 with the approval of Doxil, which was the first-ever liposomal drug delivery system. Since then, there have been notable advancements in improving the physicochemical properties of liposomal formulations. Although there have been advancements in this field, it is important to remember that the core principles established during Doxil’s approval are still relevant for all liposomal delivery systems. These principles encompass the importance of stability, achieving optimal drug release kinetics, and ensuring biocompatibility and safety (Barenholz, 2012; Wang et al., 2022).
First and foremost, stability is of utmost importance. It is crucial to ensure that liposomal formulations remain intact throughout storage and administration in order to maintain the integrity of the drug and avoid problems such as leakage or degradation. The stability of liposomes can be affected by various factors, including the lipid composition, preparation method, and storage conditions. Ensuring stability necessitates the implementation of advanced manufacturing processes and rigorous quality control measures (Liu et al., 2022).
In addition, it is crucial to achieve the ideal drug release kinetics. Striking the perfect balance between sustained release and efficient delivery to the target site is crucial for optimizing therapeutic benefits and minimizing any potential adverse effects. Designing liposomes to release their payload in a controlled manner, customized to the pharmacokinetics of the encapsulated drug, is a crucial aspect of this process. Optimizing factors like liposome size, surface charge, and the inclusion of targeting ligands can greatly enhance the release profile (Pande, 2024).
Furthermore, ensuring biocompatibility and safety is of utmost importance. It is crucial to conduct comprehensive safety evaluations to ensure that liposomal systems do not trigger immune responses or lead to any adverse reactions. The lipid composition and surface characteristics of liposomes play a crucial