Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is a primary structural component of the human brain, cerebral cortex, skin, sperm, testicles and retina. It can be synthesized from alpha-linolenic acid or obtained directly from maternal milk or fish oil. DHA is widely used as a food supplement. It was first used primarily in infant formulas. In 2004, the US Food and Drug Administration endorsed qualified health claims for DHA, and by 2007 DHA-fortified dairy items (milk, yogurt, cooking oil) started to appear in grocery stores. DHA is believed to be helpful to people with a history of heart disease, for premature infants, and to support healthy brain development especially in young children along with supporting retinal development. DHA are odorless and tasteless after processing as a food additive.
Phospholipids are a class of lipids that are a major component of all cell membranes as they can form lipid bilayers. Most phospholipids contain a diglyceride, a phosphate group, and a simple organic molecule such as choline; one exception to this rule is sphingomyelin, which is derived from sphingosine instead of glycerol. Phospholipids have been widely used to prepare liposomal, ethosomal and other nanoformulations of topical, oral and parenteral drugs for differing reasons like improved bio-availability, reduced toxicity and increased penetration. Ethosomal formulation of ketoconazole using Phospholipids showed good entrapment efficiency, stability profile and is a promising option for transdermal delivery with potential for topical application in fungal infections. Liposomes are often composed of phosphatidylcholine-enriched phospholipids and may also contain mixed Phospholipid chains with surfactant properties.