Trexall™ (methotrexate tablets, USP) (formerly Amethopterin) is an antimetabolite used in the treatment of certain neoplastic diseases, severe psoriasis, and adult rheumatoid arthritis. Chemically methotrexate is N-[4[[(2,4-diamino-6-pteridinyl) methyl] methyl-amino]benzoyl]-L-glutamic acid. The structural formula is:

Lapatinib is a small molecule and a member of the 4-anilinoquinazoline class of kinase inhibitors. It is present as the monohydrate of the ditosylate salt, with chemical name N-(3- chloro-4-{[(3-fluorophenyl)methyl]oxy}phenyl)-6-[5-({[2- (methylsulfonyl)ethyl]amino}methyl)-2-furanyl]-4-quinazolinamine bis(4- methylbenzenesulfonate) monohydrate. It has the molecular formula C29H26ClFN4O4S (C7H8O3S)2 H2O and a molecular weight of 943.5. Lapatinib ditosylate monohydrate has the following chemical structure:

ISTALOL (timolol maleate ophthalmic solution) 0.5% is a non-selective beta-adrenergic receptor blocking agent. Its chemical name is (-)-1-(tert-butylamino) –3- [(4-morpholino-1, 2, 5-thiadiazol-3-yl)oxy]-2-propanol maleate (1:1) (salt). Timolol maleate possesses an asymmetric carbon atom in its structure and is provided as the levo-isomer. The optical rotation of timolol maleate is:

Trandate (labetalol) Tablets are adrenergic receptor blocking agents that have both selective alpha1-adrenergic and nonselective beta-adrenergic receptor blocking actions in a single substance.

The topical corticosteroids constitute a class of primarily synthetic steroids used as anti-inflammatory and antipruritic agents. The steroids in this class include triamcinolone acetonide. Triamcinolone acetonide is designated chemically as 9-fluoro-11?, 16?, 17, 21-tetrahydroxypregna-1, 4-diene-3, 20-dione cyclic 16, 17-acetal with acetone. The structural formula is:

SOLTAMOX™ (tamoxifen citrate) solution, a nonsteroidal antiestrogen, is for oral administration. Each 5 mL solution contains 15.2 mg tamoxifen citrate, equivalent to 10 mg tamoxifen and the following inactive ingredients: ethanol, glycerol, propylene glycol, sorbitol solution, licorice flavor, aniseed flavor, purified water.

Theophylline is structurally classified as a methylxanthine. It occurs as a white, odorless, crystalline powder with a bitter taste. Anhydrous theophylline has the chemical name 1H-Purine-2,6-dione, 3,7-dihydro-1,3-dimethyl-, and is represented by the following structural formula:

DESYREL (trazodone hydrochloride) is an antidepressant chemically unrelated to tricyclic, tetracyclic, or other known antidepressant agents. Trazodone hydrochloride is a triazolopyridine derivative designated as 2-[3-[4-(3-chlorophenyl)-1-piperazinyl]propyl]-1,2,4- triazolo[4,3-a]pyridin-3(2H)-one hydrochloride. It is a white, odorless, crystalline powder which is freely soluble in water. Its molecular weight is 408.3. The empirical formula is C19H22ClN5O•HCl and the structural formula is represented as follows:

TAZORAC® (tazarotene gel) Gel is a translucent, aqueous gel and contains the compound tazarotene, a member of the acetylenic class of retinoids. It is for topical dermatologic use only. The active ingredient is represented by the following structural formula:

TIROSINT™ (levothyroxine sodium) capsules are soft gelatin capsules to be orally administered, which contain synthetic L-3,3',5,5'-tetraiodothyronine sodium salt [levothyroxine (T4) sodium]. Synthetic T4 is identical to that produced in the human thyroid gland.