SEDDS

Araya H, Tomita M, Hayashi M (2006) The novel formulation design of self-emulsifying drug delivery systems (SEDDS) type O/W microemulsion III The permeation mechanism of a poorly water soluble drug entrapped O/W microemulsion in rat isolated intestinal membrane by the Ussing chamber method. Drug Metab Pharmacokinet 21 45-53. 

Self-emulsifying drug delivery systems (SEDDS) are anhydrous solutions of the drug in oil containing surfactant and cosurfactant, which spontaneously emulsify when added to an excess of water. 

Spontaneous emulsification of oils carrying drugs make SEDDS good candidates for the oral delivery of hydrophobic drugs with adequate oil solubility since the drug will be presented as a fine (submicron) emulsion that has a large surface area across which diffusion can take place rapidly, thereby facilitating absorption into the body. 

Indeed, recently SEDDS themselves have been delivered as liquids absorbed onto powders such as colloidal silicon dioxide or microcrystalline cellulose (Nazzal et al., 2002). Selection of the absorbent was obviously critical to the performance of the system but, as an aside, it seems that this approach negates the rapid release properties of a SEDDS. It will be interesting to follow the future of this technology. 

Few methods exist in the literature for evaluation of performance parameters of SEDDS although some basic evaluations have been published (Groves and Mustafa, 1973). The ability of a SEDDS formulation to form small droplets on dilution is an essential feature because this determines the rates of both drug release and extent of the absorption process. This parameter is largely controlled by the nature and concentration of the primary emulsifier. Thus, phase diagrams at ambient... 

Emulsion stability of SEDDS is usually good because the droplets are small and have narrow size distributions. However, stability can be measured by determining the flocculation rates, degree of separation, or changes in the diameter of droplets formed on dilution over time during storage under various conditions. 

The final performance characteristic of any formulation, including SEDDS, is the effect produced physiologically in terms of the drug absorption. The extent of adsorption might be determined by the metabolism of the oil once ingested, the droplet size and charge and the resultant partition of the drug between the oil droplets and the excess of the aqueous phase. 

To some degree the selection of components for a SEDDS will be determined by the properties of the drug itself but, ideally, the final system concentrate prior to dilution should be... 

FIGURE 7.4 Intuitive explanation of the spontaneous formation of emulsion droplets from a SEDDS. 

Kommuru, T.R., Gurley, B., Khan, M.A., Reddy, I.K. (2001). Self-emulsifying drug delivery systems (SEDDS) of coenzyme Q10 formulation development and bioavailability assessment. International Journal of Pharmaceutics, 212, 233-246. 

FIGURE 11.1 Comparison of the bioavailability for four formulations of a lipophilic drug, RO-15-0778, in dogs. A Lipid-based SEDDS B PEG 400 solution C capsule (powder) D tablet. (AdaptedfromGershanik.T. and Benita, S. (200C ur. J. Pharm. Biopharm., 50 179-188.)... 

FIGURE 11.7 Comparison of marketed lipid-based cyclosporine formulations, Sandimmune (Olive oil SEDDS) and Neoral (Hydrolyzed Corn oil SMEDDS) in patients. (Adaptedfrom Constantinides, P.P. (1995) Pharm. Res., 12 1561-1572.)... 

Gao, P. et al. (2003) Development of a supersaturable SEDDS (S-SEDDS) formulation of paclitaxel with improved oral bioavailabilityJ. Pharm. Sci., 92 2386-2398. 

Patil, P, J. Joshi, and P. Paradkar. 2004. Effect of formulation variables on preparation and evaluation of gelled self-emulsifying drug delivery systems (SEDDS) of ketoprotetfPS Pharm Sci Te[Pg.527]

Self-Emulsifying Systems Emulsion systems have the disadvantage of being physically unstable, and over time a separation between the oil and water phases of the emulsion will occur. The use of conventional emulsions is also less attractive due to poor precision of the taken dose and the relatively large volume that has to be administered. To overcome these limitations, self-emulsifying drug delivery systems (SEDDS) have been developed. The... 

Currently, most mature dissolution controlled release systems/ technologies are applicable for water-soluble and low-water-solubility compounds (with low doses). For very poorly water-soluble compounds, dissolution controlled release systems/technologies may not be applicable because these compounds have intrinsically slow dissolution/release rates. Recently, several new technologies such as solid dispersions and self-emulsifying drug delivery systems (SEDDS) have been developed to deliver poorly water-soluble compounds at reasonable doses through enhancement of dissolution rate. These technologies have created new potentials for controlled release of poorly water-soluble compounds, often... 

Components Medium-chain triglyceride SEDDS (% w/w) Medium-chain triglyceride SMEDDS (% w/w) Long-chain triglyceride SMEDDS (% w/w)... 

Figure 1 The mean (n = 4) plasma concentration versus time profiles of Hf (panel A) and Hfm (panel B) after the oral administration of MCT SEDDS (O), MCT SMEDDS ( ), and LCT SMEDDS (A) formulations of Hf base (50 mg) to fasted beagles. (From Ref. 80.)...

N. H. Shah, M. T. Carvajal, C. I. Patel, M. H. Infeld, and A. W. Malick, Self-emulsifying drug delivery systems (SEDDS) with polyglycolyzed glycerides for improving in vitro dissolution and oral absorption of lipophilic drugs, Int. J. Pharmaceut. 106 15-23 (1994). 

Gursoy, R. N., and Benita, S. (2004), Self-emulsifying drug delivery systems (SEDDS) for improved oral delivery of lipophilic drugs, Biomed. Pharmacother. Dossier Drug Deliv. Drug Efficacy, 58,173-182. 

Biotin uptake into enterocytes is by a sodium-dependent ceurier, which also tTEinsports pantothenic acid (Section 12.2) and lipoic acid, but is inhibited by biocytin tind dethiobiotin. The carrier is found in both the smtill intestine and the colon, so both biotin and pantothenic acid synthesized by intestinal bacteria can be absorbed (Chatterjee etal., 1999 Reimaswamy, 1999 Sedd, 1999 Prasad and Ganapathy, 2000). Even at relatively high intakes (up to 80 /Limol), biotin is more-or-less completely absorbed (Zempleni and Mock, 1999b). 

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