Organogels as Matrices for Controlled Drug Delivery: A Review on the Current State
TL;DR: This review provides thorough insight into different organogelators, their mechanisms of organogels formation, various characterization techniques and their biocompatibility when administered in vivo.
Abstract: Over the last two decades, organogels have found tremendous use in the pharmaceutical, food, and cosmetics industries with notable developments as drug delivery matrices and trans and saturated fat replacers in processed foods. The functionality of organogels benefits from their ease of preparation, cost effectiveness, and ability to contain both hydrophilic and lipophilic constituents. This review provides thorough insight into different organogelators, their mechanisms of organogel formation, various characterization techniques and their biocompatibility when administered in vivo. Finally, a special treatise is given on the applications of organogels as controlled drug delivery vehicles for topical, dermal/transdermal, parenteral, oral, and nasal routes. In situ forming organogels and their potential for tailored release of incorporated active ingredients are also discussed.
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TL;DR: This review overviews the use of food grade and bio-based structurants to produce edible oleogels, aiming at fat replacement and structure-tailoring.
Abstract: The scientific and industrial communities have been giving great attention to the development of new bio-based materials with potential use in innovative technological applications. Among these materials are the structures with gel-like behavior that can be used in the cosmetic, pharmaceutical and food industries, aiming at controlling the physical properties of the final products. In the past ten years, words like oleogels and organogels have been increasingly used, the existing number of manuscripts and patents being proof of this tendency. In the food industry, oleogels can be used to control phase separation, and decrease the mobility and migration of the oil phase, providing solid-like properties without using high levels of saturated fatty acids as well as to be a carrier of bioactive compounds. In most cases, their main features are related to the reorganization process of gelators after an increase of the temperature, above the melting or glass transition temperature of the materials, known as the direct method, but it is also possible to develop oleogels by indirect methods, such as emulsification and the solvent exchange technique. In the direct methods, the reorganization is able to physically entrap oil leading to different physicochemical properties, the rheological behavior and texture properties being the frequently most studied ones. This review overviews the use of food grade and bio-based structurants to produce edible oleogels, aiming at fat replacement and structure-tailoring. Gelation mechanisms and oil phases used during oleogel production are discussed, as well as the current food applications and future trends for this kind of structure.
161 citations
TL;DR: In this article, a review of approaches taken to stabilize and structure edible oils in order to promote solid-lipid functionality for use as an alternative to animal fat for the development of healthy lipid meat products is presented.
Abstract: This paper reviews the approaches taken to stabilize and structure edible oils in order to promote solid-lipid functionality for use as an alternative to animal fat for the development of healthy lipid meat products. Interesterification and organogelation processes, the formation of oil bulking agents and the creation of structured emulsions (hydrogelled emulsion and organogelled emulsion) are described as strategies for the stabilization and structuring of edible liquid oils. Different aspects related to their composition, preparation and structural organization are described as well as their utilization in meat product formulation.
140 citations
Cites background from "Organogels as Matrices for Controll..."
...However, depending on the polarity of the liquid immobilized within the networked structure, gels may be regarded either as hydrogels (polar solvent-water) or organogels (organic solvent) (Sagiri et al., 2014)....
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...Organogels may be categorized either as physical or chemical gels depending on the type of chemical interactions involved during the gelation process (Sagiri et al., 2014)....
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...Organogelation is one of the most promising techniques to give liquid oils solid-fat functionality and has been widely used in the pharmaceutical and cosmetics industries over the last two decades with notable developments as drug delivery matrices (Hughes, Marangoni, Wright, Rogers, & Rush, 2009; Sagiri et al., 2014; Stortz et al., 2012)....
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01 Dec 2015
TL;DR: The Handbook of Encapsulation and Controlled Release as discussed by the authors covers the entire field, presenting the fundamental processes involved and exploring how to use those processes for different applications in industry, including microencapsulation.
Abstract: The field of encapsulation, especially microencapsulation, is a rapidly growing area of research and product development. The Handbook of Encapsulation and Controlled Release covers the entire field, presenting the fundamental processes involved and exploring how to use those processes for different applications in industry. Written at a level comp
136 citations
TL;DR: In this article, the potential for use of edible oleogels for lipophilic molecular delivery is discussed, as well as the relationship between lipolysis and bioaccessibility.
Abstract: Background Edible oleogels, oils structured by non-triglyceride networks, can be used for the delivery of lipid-soluble molecules due to their composition, functional properties, and structure. Different oleogelators exist, including small molecules that crystallize to form colloidal or fibrillar networks and hydrophobic polymers that self-assemble under specific processing conditions. Several types of edible oleogels have been characterized, but only select systems have been used in oral delivery applications. Scope and approach This review covers the potential for use of edible oleogels for lipophilic molecular delivery. Factors affecting lipolysis relevant to oil gelation will be discussed, as well as the relationship between lipolysis and bioaccessibility. The use of lipid-based delivery systems to increase the bioaccessibility of poorly water-soluble molecules is emphasized, and oleogels are introduced as a delivery material. The review then discusses different methods of oleogelation, and addresses properties of oleogels that may be beneficial for delivery. Key findings and conclusions Oleogel structure, mechanical strength, composition, and gelator type are factors that may affect the rate and extent of lipolysis of the material. These in turn affect the delivery of lipid-soluble molecules from the oleogel. Crystalline oleogels used in oral delivery formulations have been shown to offer increased bioaccessibility, prevention against bioactive recrystallization, and targeted or delayed bioactive release. In addition, the ability to manipulate oleogel physicochemical properties with gelator type, formulation, and processing parameters is beneficial for tailoring the material functionality. Ethylcellulose oleogels are unique food-grade polymer oleogels that could be used for delivery, similar to other crystalline oleogel systems.
126 citations
TL;DR: The role of stearic acid on physic-chemical properties of oleogel was investigated and it was indicated that heterogeneous nucleation was coupled with the one-dimensional growth of gelator fibers as the key phenomenon in the formation of Oleogels.
109 citations
Cites background from "Organogels as Matrices for Controll..."
...In general, low molecular organogelators yield fibrous networks by molecular self-assembly through noncovalent interactions [29,30]....
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References
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Book•
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TL;DR: This work states that stem cells: mechanisms of inflammation,” Annual Review of Pathology, vol.
Abstract: (SD-008). 2. L.G. Luna (Ed.), Manual of Histologic Staining Methods of the Armed Forces Institute of Pathology (3rd ed.), McGraw-Hill, New York (1968). (SD-008). Manual of Histologic Staining Methods of the Armed Forces Institute of Pathology: 9780070015074: Reference Books @ Amazon.com. stem cells: mechanisms of inflammation,” Annual Review of Pathology, vol. Luna, Manual of Histologic Staining Methods of the Armed Forces Institute.
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2,798 citations
"Organogels as Matrices for Controll..." refers background or methods in this paper
...Dynamic light scattering (DLS) and SANS experimental studies have revealed the existence of long reverse micellar aggregates in an entangled network in lecithin organogels (LOs) (183)....
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...Dipole interactions, van der Waals interactions, π -π interactions, intermolecular hydrogen bonds, London dispersive forces, and metal coordination bonds are responsible for the structuring of organic solvents by LMOGs (12, 21, 63)....
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...In general, it is believed that the presence of long chain alkyl units or steroidal groups is essential for the formation of a stable LMOG gel (21, 50, 198, 199)....
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...Small angle neutron scattering (SANS) and small angle x-ray scattering (SAXS) studies of cholesteryl anthraquinone-2carboxylate (CAQ)-based organogels have shown different types of 3-...
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...1b) and 2,3-dihexadecycloxytetracene (DHDOT) (21, 27, 65)....
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TL;DR: In this paper, a simple memory integral constitutive equation for the stress in crosslinking polymers at their transition from liquid to solid state (gel point) is proposed, which allows for only a single material parameter, the strength S[Pas1/2, and is able to describe every known viscoelastic phenomenon at the gel point.
Abstract: We suggest a very simple memory integral constitutive equation for the stress in crosslinking polymers at their transition from liquid to solid state (gel point). The equation allows for only a single (!) material parameter, the strength S[Pas1/2], and it is able to describe every known viscoelastic phenomenon at the gel point. Measurements were performed on polydimethylsiloxane model networks with balanced stoichiometry for which the crosslinking reaction has been stopped at different degrees of conversion. At the gel point, the loss and storage moduli were found to be congruent and proportional to ω1/2 over a wide range of temperature (−50°C to +180°C) and five decades of frequency ω. The hypothesis is made that this behavior is valid in the entire range 0<ω<∞. This congruence hypothesis is consistent with the Kramers‐Kronig relation and leads to a constitutive equation which shows that, for our polymer, congruent functions G′(ω)=G″(ω) are as much a rheological property at the gel point as are infinite ...
2,094 citations
TL;DR: It is proposed that overall the effects of CPEs on the skin barrier may best be explained by a Diffusion-Partition-Solubility theory.
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