SPL Set ID: d5ec4d58-c669-4ab4-ba62-b71007536854

Lamotrigine Extended-Release Tablets, 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 is a white to off white crystalline 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 extended-release tablets are supplied for oral administration as 100-mg (orange with speckles), 200-mg (blue with speckles), 250-mg (white to off-white with speckles), and 300-mg (gray with speckles) tablets. Each tablet contains the labeled amount of lamotrigine and the following inactive ingredients: colloidal silicon dioxide, FD&C Blue #1 (200 mg tablets only), FD&C Yellow #6 (100 mg tablets only), HPMC 2910, hydroxypropyl cellulose, hypromellose, iron oxide black, isopropyl alcohol, lactose monohydrate, magnesium stearate, methacrylic acid copolymer, propylene glycol, talc, and triethyl citrate. Lamotrigine extended-release tablets contain a clear modified-release membrane coating surrounding the core. The modified-release membrane coating enables a controlled release of drug throughout the gastrointestinal tract, including in the acidic environment of the stomach. The product is 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 test specifications differ from USP. molecular-structure