Drugs That Are Large in Size Are Not Able to Cross

Short Answer

Drugs that are large in size are not able to cross a membrane.[dropdown 1] involves engulfment of a drug by the cell membrane and transports it inside the cell by pinching off the filled vesicle.Vitamin B₁₂ is transported this way.Many neurotransmitters, like norepinephrine,are stored in vesicles and released to the outside of the cell by [dropdown 1].
Dropdown Choices:
Endocytosis
Exocytosis
Facilitated diffusion
Osmosis
Simple diffusion