Lucas F. Martins*
Department of Pharmacy, University of São Paulo, Brazil
Received: 02-Dec-2025, Manuscript No. dd- 25-182252; Editor assigned: 04-Dec-2025, PreQC No. dd-25-182252 (PQ); Reviewed: 15- Dec-2025, QC No. dd-25-182252; Revised: 20- Dec-2025, Manuscript No. dd-25-182252(R); Published: 30-Dec-2025, DOI: 10.4172/ dd.9.008.
Citation: Lucas F. Martins, Solid Lipid Nanoparticles, Oral Drug Delivery, and Stability. RRJ Drug Deliv. 2025.9.008.
Copyright: © 2025 Lucas F. Martins, this is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Solid lipid nanoparticles (SLNs) are an advanced nanocarrier system composed of biodegradable solid lipids stabilized by surfactants. They were developed to overcome the limitations of traditional drug delivery systems such as poor solubility, low bioavailability, and instability of many drugs. Oral drug delivery remains the most preferred route due to its convenience and patient compliance, but it is often associated with challenges including drug degradation in the gastrointestinal tract and variable absorption. In this context, SLNs have emerged as a promising approach to enhance oral drug delivery while improving drug stability [1,2].
Discussion
SLNs typically range in size from 50 to 1000 nm and consist of a solid lipid core in which the drug is dispersed or dissolved. The solid state of the lipid matrix at both room and body temperature distinguishes SLNs from other lipid-based carriers such as nanoemulsions. This solid matrix provides better protection for encapsulated drugs against chemical and enzymatic degradation, which is especially important for orally administered drugs exposed to harsh gastric conditions [3,4].
One of the major advantages of SLNs in oral delivery is their ability to improve the solubility and bioavailability of poorly water-soluble drugs. Many modern drug molecules exhibit low aqueous solubility, leading to poor absorption. SLNs maintain these drugs in a solubilized and protected form, enhancing dissolution in the gastrointestinal tract. Furthermore, the small particle size of SLNs increases the surface area, promoting intimate contact with the intestinal epithelium and improving absorption.
SLNs also enhance drug stability by protecting sensitive drugs from light, oxygen, and pH-related degradation. Encapsulation within a solid lipid matrix reduces exposure to external environmental factors during storage and after administration. In addition, SLNs can promote lymphatic uptake of lipophilic drugs, which bypasses first-pass hepatic metabolism and further improves systemic availability [5].
From a formulation perspective, SLNs offer good physical stability compared to emulsions, as the solid lipid core reduces drug leakage and minimizes particle coalescence. They can be produced using scalable techniques such as high-pressure homogenization, making them suitable for industrial manufacturing.
However, challenges remain, including limited drug loading capacity and potential drug expulsion during lipid crystallization over time. Careful selection of lipid composition and processing conditions is necessary to ensure long-term stability.
Conclusion
Solid lipid nanoparticles represent a valuable platform for improving oral drug delivery by enhancing both bioavailability and stability. Their ability to protect drugs from degradation, improve absorption, and provide physically stable formulations makes them attractive carriers in modern pharmaceutics. With continued optimization in formulation design and manufacturing, SLNs are expected to play an increasingly important role in the development of effective and stable oral drug therapies.
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