Microemulsions lecithin based

Percolated microemulsions composed of biocompatible substances, such as some lecithin-based organogels, have been considered interesting vehicles for the delivery of drugs [288],... 

Shinoda, K., Araki, M.,Sadaghiani, A., Khan, A., and Lindman, B. (1991), Lecithin-based microemulsions phase behaviour and microstructure,/. Phys. Chem., 95, 989-993. 

Schurtenberger, P., Peng, Q., Leser, M. E., and Luisi, P. L. (1993), Structure and phase behaviour of lecithin-based microemulsions A study of chanin length dependence, J. Colloid Interface Sci, 156,43-51. 

Moreno, M. A., Ballesteros, M. P., and Frutos, P (2003), Lecithin-based oil-in-water microemulsions for parenteral use pseudotemary phase diagrams, characterization and toxicity studies,/. Pharm. Sci., 92(7), 1428-1437. 

Backlund, S., Rantala, M., and Molander, O., Characterization of lecithin-based microemulsions used as a media for a cholesterol oxidase-catalyzed reaction. Coll. Polym. Sci., Ill, 1098-1103, 1994. 

Amphotericin B is an extremely potent anti-fungal agent used in the treatment of systemic fungal infections. However, delivery of amphotericin B is very difficult due to its insolubility in the water as well as commonly used oils. Furthermore, it shows several adverse effects such as nephrotoxicity. Brime et al. [109] successfully entrapped amphotericin B in the lecithin-based microemulsions and evaluated their acute toxicity in the mice in comparison to the marketed formulation. Acute toxicity studies indicated that... 

Click, A., C elebi, N., Tirnaksiz, F. and Tay, A. (2005) A lecithin-based microemulsion of rh-Insulin with aprotinin for oral administration Investigation of hypoglycemic effects on non-diabetic and STZ-induced diabetic rats. Int. J. Pharm., 298,176-185. 

Brime, B., Moreno, M., Frutos, G., Ballestros, M.P., Frutos, P. (2002) Amphotericin B in oil-water lecithin-based microemulsions Formulation and toxicity evaluation. /. Pharm. Sci., 91, 1178-1185. 

Nguyen TTL, Edelen A, Neighbors B, Sabatini DA. Biocompatible lecithin-based microemulsions with rhamnolipid and sophorolipid biosurfactants Formulation and potential applications. Journal of Colloid and Interface Science. 2010 348(2) 498-504. 

Furthermore, Corswant and Thoren investigated the effects of drugs on the structure and stability of lecithin-based microemulsions (24). It was found that felodipine, being practically insoluble in water and slightly soluble in the oil-phase used, acted like a non-penetrating oil. Thus, with increasing felodipin concentration the surfactant film curves towards the water, resulting in expulsion of the latter from the microemulsion and oil... 

Moreno, M. A., Frutos, R, and Ballesteros, M. P. 2001. Lyophilized lecithin based oil-water microemulsions as a new and low toxic delivery system for Amphotericin B. Pharmaceutical Research, 18, 344-351. 

Brime, B., Molero, G., Frutos, P., and Frutos, G. 2004. Comparative therapeutic efficacy of a novel lyophilized amphotericin B lecithin-based oil-water microemulsion and deoxycholateamphotericin B in immunocompetent and neutropenic mice infected with Candida albicans. European Journal of Pharmaceutical Sciences, 22, 451-458. 

In 1997, Avramiotis and coworkers solubilized trypsin in lecithin-based microemulsions of different compositions and studied the hydrolysis of L-lysine-p-nitroanilide [73]. Trypsin exhibited the same general characteristics of serine proteases in reverse micelles as mentioned above (Michaelis-Menten kinetics, increased stability at low water content, increased activity, bell-shaped dependence of Wq). In this study, it was shown, by using fluorescence quenching techniques and conductivity measurements, that in the presence of trypsin the structural characteristics of the reverse micelles are affected and the system compartmentalization is induced. 

Avramiotis, S., Lianos, R, Xenakis, A. 1997. Trypsin in lecithin based (w/o) microemulsions. Fluorescence and enzyme activity studies. Biocatal. Biotransform. 14, 299-316. 

By using a similar approach. Von Corswant and Thoren (23) have shown the influence of the solubilization of an active drug in lecithin-based microemulsions. By combining phase diagram determinations, NMR spectroscopic measurements and solubility determinations of the solute in aqueous and oil phases, they have determined the effect of the solute on the phase behaviour and microstructure of the microemulsion. Depending on the nature of the solute, the influence on the curvature varies. The first solute studied (felodip-ine) is water-insoluble and slightly soluble in the oil. The presence of this solute increases the polarity of the oil phase and turns the film towards the water, even if this solute has no affinity for the surfactant film. 

Von Corswant, Ch. and Thoren, P. E. G., Solubilization of sparingly soluble active compounds in lecithin based microemulsions influence on the phase behavior and microstructure, Langmuir, 15, 3710-3717 (1999). 

The use of Cremophore EL in the microemulsions is avoided nowadays due to several adverse effects such as anaphylactic shocks and histamine release [20 ]. The other important consideration is the concentration of surfactants and co-surfactants which should be minimal and preferably not exceed 20%. Furthermore, it is necessary to ensure that the microemulsion structure is preserved in the presence of the tonicity adjusting solutions such as 0.9% saline solution and preservatives. The parenteral microemulsions should also be able to withstand tests such as freeze-thaw cycling which ensure their physical stability. It has been shown that the colloidal carriers based on Solutol HS 15 can withstand freeze-thaw cycling very efficiently whereas lecithins can offer stability to autoclaving [ 112 ]. Cosurfactants such as benzyl alcohol cannot be used for intravenous applications but can be used for the small volume parenteral products up to the concentration of 1% w/v. Ethanol at concentrations above 10% usually results in the pain on injection. Co-surfactants such as glycofurol are reported to acceptable for parenteral products but there are no products based on glycofurol available for the human use. The pyrrolidone derivatives are reported to be acceptable for veterinary applications. 

Nasseria, A.A. et al.. Lecithin-stabilized microemulsion-based organogels for topical application of ketorolac tromethamine. II. In vitro release study. Iranian Journal of Pharmaceutical Research, 2003. 117 123. 

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