2.1.1. Lipids

Lipids are small hydrophobic or amphiphilic molecules [67]. They can be classified as fatty lipids of acylglycerol, phospholipids such as glycerides, seduction lipids, sterols, demonstrations of lipids played, lipids, and polylactide Kane [68]. Lipids are essential agents for the physiological and pathophysiological functioning of cells [69]. Generally, 10–1000 nm sized spherical lipid nanoparticles are synthesized [70]. All organisms consist of lipids as basic components, among other ingredients. The use of these lipids in pharmaceutical and biomedical fields can solve the problem of biocompatibility and biodegradation [71]. Besides liposomes (lipids arranged in the formation), other unique structures (e.g., hexagonal, spongy, solid structure, etc.) resulting from lipid polymorphisms also are available [72,73]. The latter have better stability and production efficiency than liposomes [48]. Lipid nanocarriers are better than polymeric nanoparticles (NPs) in terms of biocompatibility and lower toxicity, production cost and scalability, and encapsulation efficiency of highly lipophilic actives [74,75]. Lipid nanocarriers such as solid lipid nanoparticles (SLN) [76], nanostructured lipid carriers (NLC) [77], lipid nanocapsules

(LNC) [78], and drug–lipid conjugates [79] are used for various administration routes (i.e., parenteral, oral, and topical ones) [80]. Lipid polymer hybrid nanoparticles (LPHNs) can also be used in the area of bioimaging agents for medicinal diagnostics as delivery vehicles like iron oxide, quantum dots (QDs) fluorescent dyes, and inorganic nanocrystals [81].
