Colloidal drug delivery system, study

Different strategies can be carried out to improve the precorneal residence time and/or penetration ability of the active ingredient. Among them, one approach consists of using colloidal drug delivery systems such as nanoparticles. Initial studies carried out... 

There are some potential applications in which the external phase is nonaqueous. Florence and co-workers (79, 80) and Albert et al. (81) described systems in which the aqueous suspension of vesicles are dispersed in the continuous oil phase. The technique was exercised both for the study of its use in drug-delivery systems and as immunological adjuvants, as well as an intrinsically interesting colloidal system. The system is an emulsion prepared from a dispersion of niosomes in water, re-emulsified in an oil using a surfactant mixture of low HUB to achieve a stable W/0 emul-... 

Akimov Y K (2002) Fields of application of aerogels (review). Instr Exp Techniques 46 287-299 Pajonk G M (2003) Some applications of silica aerogels. Colloid Polym Sci 281 637-651 Smirnova I, Suttiruengwong S, Arlt W (2004) Feasibility study of hydrophilic and hydrophobic silica aerogels as drug delivery systems. J Non-Cryst. Solids 350 54-60... 

Mantle MD (2013) NMR and MRI studies of drug delivery systems. Curr Opin Colloid Interface... 

Studies on PEM are of interest because of the versatility of multilayer formation process with respect to variety of support materials, combination with other assembly techniques and possibility of incorporation of different functional species [1-4]. PEM are applied in chemical and biochemical sensing or preparation of new biomaterials. When colloidal particles or emulsion droplets are used as cores for polyelectrolyte deposition one can obtain hollow micro- and nanocapsules. Such capsules have potential as drug delivery systems [5] capable of sustained release [6,7], microreactors [8,9] or catalytic systems [8-10]. Detailed summaries on the properties and application of PEM prepared by LbL technique can be found in [1,11]. 

Vargha-Butler, E. I., Foldvari, M. and Mezei, M., Study of the sedimentation behaviour of liposomal drug delivery system, Colloid Surf., 42, 375-389 (1989). 

M. D. Mande, NMR and MRI Studies of Drug Delivery Systems, Curr. Opin. Colloid Interface Sci., 2013, 18, 214. 

Bernkop-Schnurch A, Humenberger C, Yalenta C (1998) Basic studies on bioadhesive delivery systems for peptide and protein drugs. Int J Pharm 165(2) 217-225 Chae SY, Jang M-K, Nah J-W (2005) Influence of molecular weight on oral absorption of water soluble chitosans. J Control Rel 102(2) 383-394 Cho EC, Lim HJ, Shim J, Park JY, Dan N, Kim J, Chang I-S (2007) Effect of polymer characteristics on structure of polymer-liposome complexes. J Colloid Interf Sci 311(1) 243-252... 

Nanoparticles Nanoparticles have been among the most widely studied particulate delivery systems over the past three decades. They are defined as submicrometer-sized polymeric colloidal particles ranging from 10 to 1000 nm in which the drug can be dissolved, entrapped, encapsulated, or adsorbed [206]. Depending on the preparation process, nanospheres or nanocapsules can be obtained. Nanospheres have a matrixlike structure where the drug can either be firmly adsorbed at the surface of the particle or be dispersed/dissolved in the matrix. Nanocapsules, on the other hand, consist of a polymer shell and a core, where the drug can either be dissolved in the inner core or be adsorbed onto the surface [207],... 

Various colloidal systems have been studied for use as potential ophthalmic delivery systems, including liposomes and nanoparticles. Liposomes are bioerodible and biocompatible systems consisting of microscopic vesicles composed of lipid bilayers surrounding aqueous compartments. Liposomes have demonstrated prolonged drug effect at the site of action but with reduced toxicity. Ophthalmic studies have included topical, subconjunctival, and intravitreal administration, but no commercial preparations are currently available for ophthalmic use. 

The following details the main SANS studies performed on a range of the most common, colloidal, polymeric, and related systems used for drug delivery. 

To date, silica has been the focus of the majority of studies on oxide-based nanos-tructured materials. One of the major reasons for this is its easy processability, high chemical inertness and exceptional colloidal stability. Moreover, silica can be processed as a thin film with controllable porosity and optical transparency. All these properties make silica ideal for use in model systems, and it is widely used in many industrial areas ranging from paints and drug delivery to composite materials. Zou et al. have recently published a detailed review on the preparation, characterization, properties, and applications of polymer/silica nanocomposites and the reader is referred to this review for in-depth description of the various synthetic routes [16]. 

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