*2.1.2 Phosphoinositides (phosphatidyl inositols)*

Phosphoinositides are phospholipids which have cyclic hexahydroxy alcohol called inositol attached to phosphoric acid. The phosphoinositides on hydrolysis

**Figure 3.** *Structure of lecithin.*

#### **Figure 4.**

*Structure of Phosphatidyl Ethanolamaine.*

#### **Figure 5.**

*Structure of Phosphatidyl serine.*

**Figure 6.** *Structure of Phosphatidal choline.*

**Figure 7.** *Structure of Phosphatidal ethanolamine.*

*Drug Delivery through Liposomes DOI: http://dx.doi.org/10.5772/intechopen.97727*

**Figure 8.** *Structure of Phosphatidal serine.*

gives glycerol, fatty acids, inositol and phosphoric acid with 1 or 2 or 3 moles. Because of this monophosphoinositide (See **Figure 9**), diphosphoinositide and triphosphoinositide (See **Figure 10**) are found. Phosphoinositides are glycolipids which contains carbohydrate residue.

#### *2.1.3 Phosphosphingosides (=sphingomyelins)*

Sphingomyelins are structurally different from that of other phospholipids by lacking glycerol moiety and presence of nitrogeneous sphingosine or dihydrosphingosine along with choline. These are electrically charged molecules with polar head phosphocholine.

**Figure 10.** *Structure of Triphosphoinositide.*

**Figure 11.** *Structure of cholesterol.*
