Page 235 - Pharmaceutics IV (02-06-01305)
P. 235
30/03/2024
1. Effect of particle size
(aerodynamic size distribution)
- Access to distal airways is a function of particle size
- Large particles (> 7 microns) will be lost in the
gastrointestinal tract
- Small particles (< 3 microns) will be lost in exhaled
breathe
- Intermediate particles (3 to 7 microns) reach the
actual site of action
Dr ALyaa Ramadan, AU 45
45
2. Effect of molecular size
- Higher the molecular size, lower the nasal absorption
- A good systemic bioavailability can be achieved for
molecules with a molecular weight of up to 1000
Daltons when no absorption enhancer is used
Dr ALyaa Ramadan, AU 46
46
23
