Solid Lipid Nanoparticles as a Promising Strategy for Enhancing Oral Bioavailability of Poorly Absorbed Drugs: A Comprehensive Review

Abstract

Recent advances in nanotechnology-based oral drug delivery systems have provided promising approaches to address the challenges posed by drugs with poor bioavailability. Ahighly present of newly developed pharmaceutical compounds have low oral bioavailability. Due to their low aqueous solubility, intestinal permeability, and extensive first-pass metabolism. Addressing these challenges continues to be a key priority in pharmaceutical research. Solid lipid nanoparticles (SLNs) have gained considerable attention as lipid-based nanocarriers that can improve drug solubility, protect sensitive compounds from degradation in the gastrointestinal tract, enhance intestinal permeability, and support controlled drug release. They are considered a promising delivery system for oral medications. Because they have several advantageous characteristics, such as their biocompatibility, ability to encapsulate both hydrophilic and lipophilic drugs, and suitability for large-scale production.

This review draws on a wide range of studies published between 1993 and 2025. with a particular focus on research exploring the use of SLNs to enhance oral bioavailability. The use of old references to document the original information.

The reviewed studies consistently show that SLN-based formulations can markedly enhance drug bioavailability, with reported improvements generally ranging from about 2- to 12-fold, depending on the drug’s physicochemical characteristics and the formulation conditions.

The review provides a comprehensive overview of SLNs, covering formulation strategies, preparation methods, and key characterization techniques. It also offers a critical evaluation of their main advantages and potential limitations. Particular attention is given to their role in oral drug delivery and their effectiveness in enhancing systemic drug absorption.

When taken as a whole, SLNs offer a reliable and flexible delivery system that has great potential to improve the oral bioavailability of medications that are poorly absorbed and to further the creation of contemporary therapeutic formulations.