Lipidic matrices

Lipidic matrices are constituted by a drug suspended or dissolved in lipidic excipients in which the drug is embedded. 

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To detect dynamic featnres of colloidal preparations, additional methods are required. Nuclear magnetic resonance spectroscopy allows a rapid, repeatable, and noninvasive measurement of the physical parameters of lipid matrices withont sample preparation (e.g., dilution of the probe) [26,27]. Decreased lipid mobility resnlts in a remarkable broadening of the signals of lipid protons, which allows the differentiation of SLN and supercooled melts. Because of the different chemical shifts, it is possible to attribute the nuclear magnetic resonance signal to particnlar molecnles or their segments. 

Portmann, M Landau, E. M., and Luisi, P. L. (1991). Spectroscopic and rheological studies of enzymes in rigid lipidic matrices the case of a-chymotrypsin in a lysolecithin/water cubic phase. J. Phys. Chem., 95, 8437 0. 

Dermal and transdermal delivery requires efficient penetration of compounds through the skin barrier, the bilayer domains of intercellular lipid matrices, and keratin bundles in the stratum corneum (SC). Lipid vesicular systems are a recognized mode of enhanced delivery of drugs into and through the skin. However, it is noteworthy that not every lipid vesicular system has the adequate characteristics to enhance skin membrane permeation. Specially designed lipid vesicles in contrast to classic liposomal compositions could achieve this goal. This chapter describes the structure, main physicochemical characteristics, and mechanism of action of prominent vesicular carriers in this field and reviews reported data on their enhanced delivery performance. 

Lipid Matrices These matrix tablets are formed with lipid polymers with low melting point. The drug is dissolved or solubilized in the melted lipid, such as cetyl... 

Evrard, B. Delattre, L. In vitro evaluation of lipid matrices for the development of the sustained-release sulfamethazine bolus for lambs. 1996, 22 (2), 111-118. 

FIG U RE 6.6 IL-6 production of peritoneal macrophages of the mouse after 20 h of incubation with SLN (different lipid matrices and poloxamer 188) or Lipofundin MCT in different concentrations (means + standard deviation, n = 3, untreated cells have a IL-6 secretion of 1). 

In the microencapsulation of probiotics, matrices used in the formula cannot be cytotoxic or antimicrobial. When microparticles go through the stomach, bacteria have to continue retained and protected from the external acid environment, and they should be released only in the intestines, where immunological signaling will occur (Cook et al., 2012). Little is known about the effect of microencapsulation with lipid matrices on probiotic survival. However, it is known than fat/oils are barriers against oxygen and moisture. 

Therefore, the possibility of encapsulating probiotics with lipid matrices is an interesting proposal, once lipids are digested by intestinal lipases, enabling the release of the microorganisms in the site where they are supposed to act, which is essential ensure their health benefits (Nori et al., 2009 Favaro-Trindade et al., 2011 Pedroso et al. 2012, 2013 Okuro et al. 2013b), as shown in Figure 5.2. 

Muller RH, Radtke M, Wissing SA (2002a) Nano structured lipid matrices for improved microencapsulation of drugs. International Journal of Pharmaceutics 242 121-128. 

In their natural state many proteins are bound into hydrophobic lipid matrices. The energetics of charge separation and mobility are governed largely by the dielectric constant of the surrounding medium. Calculations have shown that the internal structures have an effective... 

Solid Lipid Matrices with High Amounts of Lecithin... 

The bulk lipid mixtures and the corresponding nanoparticles were intensively studied by Schubert et al. using different methods (e.g. DSC, X-ray, NMR, electron microscopy) to get a deeper insight into the structure of this kind of lipid matrices. The lecithin was dissolved in the molten hard fat (Softisan 154) and colloidal dispersions were prepared after solidification of the lipid matrices by high-pressure homogenization. Solutol was added to the water phase for the stabilization of the nanoparticles. 

Medina I, Alcantara D, Gonzalez MJ, Torres P, Lucas R, Roque J, Plou FJ, Morales JC (2010) Antioxidant activity of resveratrol in several fish lipid matrices effect of acylation and glucosylation. J Agric Food Chem 58 9778-9786 Lunn J (2006) Superfoods. Nutr Bull 31 171-172... 

Carbon chains tipped with a particular common head group chemical. .L. Toppozini et al. Adenosine monophosphate forms ordered arrays in multilamellar lipid matrices insights into assembly of nucleic acid for primitive life. 2013. PLoS One 8(5), p. e62810. DOl 10.1371/journal.pone.0062810. 

M. Ozyazici, E.H. Gokce, and C. Ertan, Release and diffusional modeling of metronidazole lipid matrices, Eur. J. Pharm. Biopharm., 63,331-339,2006. 

Medina, I., I. Undeland, and K. Larsson. 2012. Activity of caffeic acid in different fish lipid matrices A review. Food Chem. 131 730-740. 

Polymeric matrix systems are the most widely employed for the formulation of oral prolonged release pharmaceutical dosage forms due to their simple and low-cost manufacturing process. There are three main types of pharmaceutical matrices inert, hydrophilic and lipidic matrices, being hydrophilic and inert matrices the most employed ones.. 

Dpm 1 p is sensitive to the physical state of its membrane environment, and lipid matrices that form destabilized bilayers promote the association of the enzyme with Dol-P and are necessary for optimal activity [51[. More specific modulation of Dol-P-Man synthase activity may be achieved through phosphorylation by cAMP-dependent kinase [52], and the six Dpmlp sequences indeed all have a potential site for phosphorylation by that enzyme [46]. 

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