SPL Set ID: c9ae08c5-275d-44b3-9d1e-5d8fedc21b96

Dorzolamide hydrochloride and timolol maleate ophthalmic solution, USP is the combination of a topical carbonic anhydrase inhibitor and a topical beta-adrenergic receptor blocking agent. Dorzolamide hydrochloride is described chemically as: ( 4S-trans )-4- (ethylamino)- 5,6-dihydro-6-methyl- 4H -thieno[2,3- b ]thiopyran-2-sulfonamide 7,7-dioxide monohydrochloride. Dorzolamide hydrochloride is optically active. The specific rotation is: Image Image Its empirical formula is C 10 H 16 N 2 O 4 S 3 •HCl and its structural formula is: Image Image Dorzolamide hydrochloride has a molecular weight of 360.91. It is a white to off-white, crystalline powder, which is soluble in water and slightly soluble in methanol and ethanol. Timolol maleate is described chemically as: (-)-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: Image Image Its molecular formula is C 13 H 24 N 4 O 3 S•C 4 H 4 O 4 and its structural formula is: Image Image Timolol maleate has a molecular weight of 432.50. It is a white, odorless, crystalline powder which is soluble in water, methanol, and alcohol. Timolol maleate is stable at room temperature. Dorzolamide hydrochloride and timolol maleate ophthalmic solution, USP is supplied as a sterile, clear, colorless to nearly colorless, isotonic, buffered, slightly viscous, aqueous solution. The pH of the solution is approximately 5.65, and the osmolarity is 242-323 mOsM. Each mL of Dorzolamide hydrochloride and timolol maleate ophthalmic solution, USP contains 20 mg dorzolamide (22.26 mg of dorzolamide hydrochloride) and 5 mg timolol (6.83 mg timolol maleate). Inactive ingredients are sodium citrate, hydroxyethyl cellulose, sodium hydroxide, mannitol, and water for injection. Benzalkonium chloride 0.0075% is added as a preservative. a c b f