Pharmaceuticals lecithin applications

Complexes of starch with lecithin are useful for pharmaceutical applications, as they form molding compositions with good release characteristics and dimensional stability.890 Solutions of approximately 10% of lecithin in starch are utilized for fiber sizing and as cold-soluble adhesives.891 Only 3-5% of lecithin in starch produces a cold-water paste.892 A complex of starch with lecithin increases the adhesiveness of some synthetic polymers.893... 

For the most part, the greatest percentage of lecithin is used in foods. The second highest use is in animal feeds, followed by industrial applications. Paints and other coatings consume a major portion of the nonfood lecithin. Pharmaceuticals, including dietary supplements, and inks and cosmetics, however, also consume significant portions. 

In recent years, pharmaceutical patents accounted for almost 25% of the nonfood patent activity. Pharmaceutical applications, particularly those involving liposomes, should require increasing quantities of refined lecithins. An increased demand for lecithin as a dietary supplement is also anticipated, as the result of dietary reference intakes being established for choline. Besides being a multifunctional food ingredient, lecithin has the benefit of being a widely recognized health food. 

Lecithins are used in a wide variety of pharmaceutical applications see Table I. They are also used in cosmetics and food products. 

The utilization of soybean lecithins is reviewed by Schneider (1986). Table 2.12 summarizes the most common applications in the food, feed, cosmetic, and pharmaceutical industries. The food industry relies on lecithin in bakery, beverage, and confectionery product development because of its functionalities. 

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. 

Bhatia, A. et al.. Tamoxifen-loaded lecithin organogel (LO) for topical application Development, optimization and characterization. International Journal of Pharmaceutics, 2013.444(1-2) 47-59. 

For medical or pharmaceutical applications, attention must be paid to the problems that can be caused by the possible toxicity of the surfactant remaining in the final product. Antonietti et al. [89] proposed the use of natural, nontoxic, and nondenaturing surfactants based on mixtures of lecithin and sodium chlolate for the formation of globular microemulsions. Pure lecithin is known to form bilayers or liposomes. The role of sodium cholate is to increase the curvature and flexibility of the interfacial layer, allowing the formation of small droplets. The final microlatex particles have a size ranging from 22 to 40 nm, depending on surfactant composition and concentration. The ability to functionalize the surface of these particles was demonstrated by the incorporation of protein molecules. 

The potential technical and commercial applications of microemulsions are mainly linked to their unique properties such as thermodynamic stability, optical clarity, and high solubilization capacity. However, the most critical problem regarding the use of microemulsions in the food, cosmetic, and pharmaceutical fields is the toxicity of their partial components. Formulation and characterization of nontoxic microemulsions based on naturally occurring amphiphiles and different oils have been studied for almost two decades. The first attempt to use natural biodegradable surfactants for the formulation of nontoxic microemulsions was reported by Shinoda et al. [ 155,156]. In this regard, soybean lecithin is a combination... 

Processed phospholipids ( special lecithins ) are used in the manufacturing of paints, leather, and numerous foods such as bakery goods, chocolate, margarines, etc. Derivatized phospholipids also have specific applications in pharmaceuticals and personal care products [60]. Although several chemical and physical modifications of lecithins have been adopted by industry [61], there is a clear scope for the application of enzymes to the transformation of... 

Formulation Surfactants are used for the formulation of many pharmaceutical formulations such as suspensions, emulsions, multiple emulsions, semisolid and gels for topical application. In all cases the surfactants must be approved by the Food and Drug Admins-tration (FDA) and this limits the choice in pharmaceutical applications. Several surfactant molecules have been approved by the FDA, both of the ionic and nonionic type. The latter are perhaps the most widely used molecules in pharmaceuticals, e.g., sorbitan esters (Spans) and their ethoxylated analogues (Tweens). Polymeric surfactants of the PEO-PPO-PEO block type or Poloxamers (ICl, U.K.) are also used in many formulations. Many pharmaceutical emulsions, e.g., lipid and anesthetic emulsions, are formulated using egg lecithin which has to be pure and free from any toxic impurities. 

Properties such as large interfacial area and an ability to solubilize both oil-soluble and water-soluble reactants in a single phase system makes microemulsions ideal as reaction media (Flanagan and Singh, 2006 Gaonkar and Bagwe, 2002). For example, Morgado and co-workers (1996) nsed a continnons reversed micellar system to synthesize lysophospholipids and free fatty acids from lecithin hydrolysis, with applications to the food, pharmaceutical and chemical industries. Hydrolysis was catalyzed by porcine pancreatic phospholipase A. Carvalho and Cabral (2000) reviewed the use of reversed micellar systems as reactors to carry out lipase-catalyzed esterification, biocatalysis, transesterificadon, and hydrolysis reactions. 

Manufacturers treat the crude oily lecithin in various ways and extract products with various degrees of purity and specificity. Products such as plastic lecithins, deoiled lecithins, phosphatidyl choline-enriched lecithins, pure phosphatidylcholines (>98% PC), phosphatidylserines (PS) phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidic acids (PA) mixture of fatty acids or mixtures of phospholipids with any particular fatty acid have been separated and are commercially available. Prices range from less than 1 per kilogram (crude lecithins) to thousands of U.S. dollars (pure selected fatty acid PC or PS). The inexpensive mixtures are widely used in food applications, and the purified lipids are used in very sophisticated pharmaceutical applications for drug stabilization, delivery, and targeting. 

---