SPL Set ID: 4bd7193f-a81a-4909-90c2-7f324fc6ddfd

Lamotrigine, USP an AED of the phenyltriazine class, is chemically unrelated to existing AEDs. Lamotrigine’s chemical name is 3,5-diamino-6-(2,3-dichlorophenyl)- as -triazine, its molecular formula is C 9 H 7 N 5 Cl 2 , and its molecular weight is 256.1. Lamotrigine is a white or almost white powder and has a pKa of 5.7. Lamotrigine is slightly soluble in anhydrous ethanol and in 0.1M hydrochloric acid. The structural formula is: Lamotrigine extended-release tablets, USP are supplied for oral administration as 200 mg, blue, round, biconvex film-coated tablets; 250 mg, purple, caplet shaped, biconvex film-coated tablets; and 300 mg, grey, caplet shaped, biconvex film-coated tablets. Each tablet contains the labeled amount of lamotrigine and the following inactive ingredients: lactose monohydrate, povidone K-30, hypromellose, colloidal silicon dioxide, magnesium stearate, methacrylic acid and ethyl acrylate copolymer, silicon dioxide, triethyl citrate, titanium dioxide, polyethylene glycol 400, ferrosoferric oxide (250 mg and 300 mg tablets only), FD&C Blue No. 2 Aluminum Lake (200 mg and 250 mg tablets only), carmine (250 mg tablet only). Tablets are imprinted with edible black ink containing shellac, propylene glycol and ferrosoferric oxide. Lamotrigine extended-release tablets, USP contains modified-release, erodible matrix as the core. The core tablet is coated with a modified enteric coat to enable a controlled release of drug in the acidic environment of the stomach. The combination of the modified-release core and the modified enteric coating are designed to control the dissolution rate of lamotrigine over a period of approximately 12 to 15 hours, leading to a gradual increase in serum lamotrigine levels. FDA approved dissolution testing specifications differ from USP. Structure