SPL Set ID: 3dfdcc2d-b7c5-7abf-e063-6394a90a24a6

Lamotrigine, 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 256.09. Lamotrigine USP is a white to pale cream-colored powder and has a pK a of 5.7. Lamotrigine is very slightly soluble in water (0.17 mg/mL at 25°C) and slightly soluble in 0.1 M HCl (4.1 mg/mL at 25°C). The structural formula is: Lamotrigine tablets USP are supplied for oral administration as 25 mg (white to off-white), 100 mg (peach), 150 mg (cream), and 200 mg (blue) tablets. Each tablet contains the labeled amount of lamotrigine USP and the following inactive ingredients: microcrystalline cellulose, lactose monohydrate, povidone, sodium starch glycolate, magnesium stearate; FD&C yellow No 6 (100 mg tablet only); ferric oxide yellow (150 mg tablet only); and FD&C blue No 2 lake (200 mg tablet only). Meets USP dissolution test 3.