Abstract

Aditi Singh, Tirthankar Choudhury

ABSTRACT

Oral drug delivery always remains the most preferred route of drug administration due to its convenience, patient compliance, and importantly the cost-effectiveness. However, many therapeutic agents may suffer from the poor aqueous solubility, extensive first-pass metabolism and also the limited bioavailability, which may restrict their clinical efficacy. Solid-lipid nanoparticles (SLNs) have emerged potently as a most promising nanocarrier system which is capable of addressing these challenges by combining the advantages of the lipid-based formulations with the nanoscale drug delivery system. This review comprehensively explores the potential of SLNs in the sustained release oral delivery system, highlighting their abilities to enhance the bioavailability and to most effective therapeutic outcomes. The paper also focuses on the overview of SLNs fundamentals, including the composition, preparation techniques and the physicochemical properties that governs the drug encapsulation and drug release. Advancement in the formulation strategies, such as lipid selection, surfactant optimization, and scale-up approaches, are critically examined in this paper. Furthermore, the review also emphasizes the pharmacokinetic improvements which are achieved through SLNs, particularly their role in the promotion of the lymphatic transport and bypassing the hepatic metabolism. Applications across diverse the therapeutic domains which includes the anticancer agents, antiretrovirals, anti-inflammatory drugs and nutraceuticals which are presented with the case studies demonstrating the enhanced oral bioavailability. Characterization techniques such as dynamic light scattering, electron microscopy, and differential scanning calorimetry are also outlined to provide a framework for evaluating the SLNs performance. Despite their promises, challenges such as lipid polymorphism, drug leakage, and regulatory hurdles remains the significant barriers to the clinical translation. Finally, future perspectives are discussed, including hybrid lipid-polymer systems, stimuli-responsive carriers and personalized nanomedicine approaches. By consolidating the current available knowledge and identifying the research gaps, this review collectively underscores the transformative potential of the sustained release oral SLNs in the modern drug delivery and encourages the further innovation towards the clinical application.