Table 1.

Approximate particle size range for drug deposition in various body organs via different dosage forms and routes of administration.

Route of Administration/Dosage Form	Particle Size Range
Lymphatic (RES) *	10–50 nm
Long-circulating carriers (brain, tumour)	50–200 nm
Transdermal	10–600 nm
Intravenous/intramuscular	200–2000 nm
Ocular	100–3000 nm
Aerosol	1–10 µm
Nasal	8–20 µm

* Reticuloendothelial system.