Maria L. Gonzalez*
Department of Pharmaceutical Technology, University of Barcelona, Spain
Received: 02-Sep-2025, Manuscript No. dd- 25-182243; Editor assigned: 04-Sep-2025, PreQC No. dd-25-182243 (PQ); Reviewed: 15-Sep-2025, QC No. dd-25-182243; Revised: 20-Sep-2025, Manuscript No. dd- 25-182243(R); Published: 29-Sep-2025, DOI: 10.4172/dd.9.004.
Citation: Maria L. Gonzalez, Nanoemulsions, Oral Drug Delivery and Bioavailability. RRJ Drug Deliv. 2025.9.004.
Copyright: © 2025 Maria L. Gonzalez, 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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Oral drug delivery is the most widely used route of administration due to its convenience, safety, and patient acceptance. However, many drugs exhibit poor oral bioavailability because of low solubility, instability in the gastrointestinal tract, and extensive first-pass metabolism. Bioavailability refers to the fraction of an administered dose that reaches systemic circulation in an active form. Improving bioavailability is a major goal in pharmaceutical development. Nanoemulsions have emerged as an advanced drug delivery system capable of enhancing the oral absorption of poorly water-soluble drugs [1,2].
Discussion
Nanoemulsions are thermodynamically or kinetically stable colloidal systems consisting of oil, water, surfactant, and sometimes a co-surfactant, with droplet sizes typically in the range of 20–200 nm. Their small droplet size provides a large surface area for drug dissolution and absorption. Unlike conventional emulsions, nanoemulsions are transparent or slightly translucent and show high physical stability against creaming and sedimentation [3,4].
One of the main advantages of nanoemulsions in oral delivery is their ability to improve the solubility of lipophilic drugs. Many new drug candidates belong to the Biopharmaceutics Classification System class II and IV, characterized by low solubility and limited bioavailability. By dissolving these drugs in the oil phase of a nanoemulsion, they remain in a solubilized state in the gastrointestinal tract, preventing precipitation and enhancing absorption [5].
Nanoemulsions also improve drug permeability across the intestinal epithelium. The presence of surfactants can temporarily alter membrane fluidity and inhibit efflux transporters, promoting drug transport. In addition, lipid-based nanoemulsions stimulate the formation of mixed micelles and promote lymphatic uptake, which can bypass first-pass hepatic metabolism. This mechanism significantly increases the systemic availability of drugs that are extensively metabolized in the liver.
From a pharmacokinetic perspective, nanoemulsions often produce higher peak plasma concentrations and faster onset of action compared to conventional oral formulations. They can also reduce variability in drug absorption between patients. Furthermore, nanoemulsions are suitable for delivering a wide range of compounds, including anticancer, anti-inflammatory, and antiviral agents.
Despite their benefits, challenges include the selection of safe excipients, potential gastrointestinal irritation, and scalability of manufacturing processes. Long-term stability and regulatory acceptance must also be addressed for widespread clinical use.
Conclusion
Nanoemulsions represent a promising strategy to overcome the limitations of oral drug delivery, particularly poor solubility and low bioavailability. By enhancing drug dissolution, intestinal permeability, and lymphatic transport, nanoemulsions significantly improve systemic drug exposure. Continued research and technological development are expected to expand their application in modern pharmaceutical formulations and improve therapeutic outcomes.
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