Novartis Exelon® Patch now FDA approved to treat patients across all stages of Alzheimer’s disease
Exelon Patch (rivastigmine transdermal system) contains rivastigmine, a reversible cholinesterase inhibitor known chemically as (S)- 3-[1-(dimethylamino) ethyl]phenyl ethylmethylcarbamate. It has an empirical formula of C14H22N2O2 as the base and a molecular weight of 250.34 (as the base). Rivastigmine is a viscous, clear, and colorless to yellow to very slightly brown liquid that is sparingly soluble in water and very soluble in ethanol, acetonitrile, n-octanol and ethyl acetate.
The distribution coefficient at 37°C in n-octanol/phosphate buffer solution pH 7 is 4.27.
Exelon Patch is for transdermal administration. The patch is a four-layer laminate containing the backing layer, drug matrix, adhesive matrix and overlapping release liner (see Figure 1). The release liner is removed and discarded prior to use.
Figure 1: Cross Section of the Exelon Patch
Layer 1: Backing Film
Layer 2: Drug Product (Acrylic) Matrix
Layer 3: Adhesive (Silicone) Matrix
Layer 4: Release Liner (removed at time of use)
Excipients within the formulation include acrylic copolymer, poly(butylmethacrylate, methylmethacrylate), silicone adhesive applied to a flexible polymer backing film, silicone oil, and vitamin E.