Abstract and Introduction
Abstract
There has been a resurgence of interest in nanoemulsions for various pharmaceutical applications since low-energy emulsification methods, such as spontaneous or self-nanoemulsification, have been described. Self-nanoemulsifying drug delivery systems (SNEDDS) are anhydrous homogenous liquid mixtures consisting of oil, surfactant, drug and coemulsifier or solubilizer, which spontaneously form oil-in-water nanoemulsion of approximately 200 nm or less in size upon dilution with water under gentle stirring. The physicochemical properties, drug solubilization capacity and physiological fate considerably govern the selection of the SNEDDS components. The composition of the SNEDDS can be optimized with the help of phase diagrams, whereas statistical experimental design can be used to further optimize SNEDDS. SNEDDS can improve oral bioavailability of hydrophobic drugs by several mechanisms. The conversion of liquid SNEDDS to solid oral dosage forms or solid SNEDDS has also been achieved by researchers. Solid SNEDDS can offer better patient compliance and minimize problems associated with capsules filled with liquid SNEDDS.
Introduction
Nanotechnology has become a buzzword in pharmaceutical sciences and efforts are ongoing to extend its applications in various streams of pharmaceutical sciences. Nanotechnology has dramatically influenced drug delivery research over the last two decades and several nanoscale technologies/carriers have been and are being explored for improving therapeutic performance of drugs. The several ways by which nanoscale technologies can improve therapeutic efficacy of drugs are:
Improving solubility of hydrophobic drugs;
Improving permeability or transport of poorly permeable drugs (class III and IV drugs as per the Biopharmaceutical Classification System [BCS]);
Modulating biodistribution and drug disposition of drugs;
Preventing degradation of drugs in physiological milieu;
Enabling targeted delivery of the drugs to the site of action.
The nanoscale technologies can be broadly classified into: lipid-based nanocarriers, polymeric nanocarriers, inorganic nanocarriers, and drug nanoparticles or nanosuspensions.[1]
Lipid nanocarriers include lipid core micelles, liposomes, microemulsions, nanoemulsions, solid lipid nanoparticles and nanostructured lipid carriers, whereas polymeric nanocarriers encompass polymeric micelles, polymeric nanoparticles and nanocapsules, dendrimers and polymer–drug nanoconjugates. Inorganic nanocarriers include nanostructures containing various inorganic metals, for example iron oxide (magnetic) nanoparticles, gold nanoparticles, calcium phosphate nanoparticles and quantum dots, whereas drugs in nanoparticulate form can be used as nanosuspensions. All these colloidal nanocarriers are extensively being studied in drug delivery research and have demonstrated great potential in improving drug delivery by various routes of administration.[1–3] The present article focuses on nanoemulsions and more specifically on the spontaneously forming nanoemulsions or self-nanoemulsifying systems for oral drug delivery.
Nanomedicine. 2010;5(10) © 2010 Future Medicine Ltd.
Cite this: Self-nanoemulsifying Drug Delivery Systems: Formulation Insights, Applications and Advances - Medscape - Dec 01, 2010.
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