Lecture 6
Week 6
Particle Based Drug Delivery Systems
References
LANGER, R.S. & PEPPAS, N.A. (1981) Present and future applications of biomaterials in controlled drug delivery systems.
Biomaterials .
2 , 201-214.
Solvent Casting Method
Solvent Casting Method
PROTEIN
SOLUTION
Double Emulsion Method
POLYMER-DCM
SOLUTION
ADD TO PVA IN
WATER & MIX
ULTRA
SONICATION
PRIMARY
EMULSION (W/O)
SECONDARY
EMULSION
(W/O/W)
SOLVENT
EVAPORATION
FILTRATION AND
DRYING
Spray Dried Microspheres
• Inlet temperature
• Polymer concentration
• Pump feed rate
• Aspirator ratio
• Compressed air flow rate
• Drug loadings
F.J. Wang and C.H. Wang, “Sustained Release of Etanidazole from Spray Dried Microspheres Prepared by Non-halogenated Solvents”,
J. Controlled Release , 81 263-280 (2002).
Microsphere surface morphology using different polymer solution concentrations
A B
C D
F.J. Wang, T.K.Y. Lee and C.H. Wang , “PEG Modulated Release of Etanidazole from Implantable PLGA/PDLA Discs”,
Biomaterials ,
23 3555-3566 (2002)..
Degradation of microspheres
PLGA 50:50
1 month
PLGA 65:35
1 month
PLGA 85:15
3 month
PDLA
3 month
F.J. Wang, T.K.Y. Lee and C.H. Wang , “PEG Modulated Release of Etanidazole from Implantable PLGA/PDLA Discs”,
Biomaterials , 23 3555-3566 (2002).
Modulation of release by PEG
100
90
80
70
60
50
40
30
20
10
0
0
PEG 8000, 10%
PEG3350, 10%
PEG1145, 5%
PEG3350, 5%
20 40 60
Release Time (days)
80 100 small discs (diameter = 5mm, thickness =1mm)
60
50
40
30
20
100
90
80
70
10
0
0 20 40 60
Release Time (days)
PEG8000 10%
PEG3350 10%
PEG1145 5%
PEG 3350 5%
80 large discs (diameter =13mm, thickness = 1mm )
100
