Particle Based Drug Delivery Systems

ReferencesLANGER, R.S. & PEPPAS, N.A. (1981) Present and future applications of biomaterials in controlled drug delivery systems. Biomaterials. 2, 201-214.

Week 6

Solvent Casting Method

Solvent Casting Method

POLYMER-DCM SOLUTION

ADD TO PVA IN WATER & MIX

SECONDARY EMULSION (W/O/W)

SOLVENT EVAPORATION

FILTRATION AND DRYING

PRIMARY EMULSION (W/O)

ULTRA SONICATION

PROTEIN SOLUTION

Double Emulsion Method

•Inlet temperature

•Polymer concentration

•Pump feed rate

•Aspirator ratio

•Compressed air flow rate

•Drug loadings

Spray Dried Microspheres

Microsphere surface morphology using different polymer solution concentrations

A B

DC

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).

Degradation of microspheres

PLGA 65:351 monthPLGA 50:50

1 month

PLGA 85:153 month

PDLA3 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

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100

Release Time (days)

Cu

mu

lati

ve

Re

lea

se

(%

)

PEG 8000, 10%

PEG3350, 10%

PEG1145, 5%

PEG3350, 5%

small discs (diameter = 5mm, thickness =1mm)

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100

Release Time (days)

Cu

mu

lati

ve

Re

leas

e (

%)

PEG8000 10%

PEG3350 10%

PEG1145 5%

PEG 3350 5%

large discs (diameter =13mm, thickness = 1mm)

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).