orally dissolving tablets (ODTs), also
called fast-melt tablets. The chal-
lenges in formulating ODTs are to
provide rapid disintegration, high
drug loading, and good mouth-feel.
Calcium silicate, fumed silica, and
precipitated silica are useful as co-dis-
integrants. Use level depends on the
type and grade of silica. For calcium
silicate, it could reach 30 percent.
Preparation of moisture-activated
dry granulations (MADGs)
MADGs is a granulation process
developed at Bristol-Myers Squibb in
the 1980s that reduces the number of
processing steps and production costs
compared to conventional wet granu-
lation [1]. This process uses water to
wet and agglomerate the powder bed,
but no drying is required. The process
is particularly useful when granulating
heat-sensitive APIs. Furthermore, the
desired particle size distribution of the
granulation can be obtained without a
sizing step by optimizing process con-
ditions. Silica's role is to adsorb the
small amount of granulating water
used to wet the binder. The amount of
silica needed depends on a number of
factors, including mixing conditions,
amount and type of granulating solu-
tion, and amount of binder. As a gen-
eral guide, a granulation using 2 per-
cent water will require about 1.5
percent silica. High-porosity precipi-
tated silica and granulated fumed sil-
ica perform well in this application.
Evonik, a supplier of fumed silica,
offers a video about the process:
bit.ly/TabCapMADG.
T&C
Reference
1. Ullah, L., Corrao, R.G., Lipper,
R.A., Moisture-activated dry granula-
tion: A general process. Pharm Tech,
1987, 11(9) 48.
J o h n A . M c C a r t y i s p r e s i d e n t o f
McCarty Pharma Consultants, PO
B o x 6 6 1 5 6 8 , M i a m i S p r i n g s , F L
33266. Tel. 305 887 9220. E-mail:
john.mccarty@comcast.net. He is also a
member of Tablets & Capsules' Technical
Advisory Board.
42 April 2015 Tablets & Capsules
www.tabletscapsules.com
formulation
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