Siliconization -

why siliconization is required for glass vials and cartridges?

Siliconization: Applying an aqueous emulsion of a polydimethysiloxanic oil to make them extremely hydrophobic. This hydrophobic nature will help us for clean and complete drainage from multiple dose vials, lubricity to glass cartridges in disposable syringes.
It also help to minimize the interaction between dosage form and glass vial surface.
It also prevents high viscosity products from sticking to the internal surface of the vials.