DESCRIPTION
COSOPT * (dorzolamide hydrochloride-timolol maleate ophthalmic solution) is the combination of a topical carbonic anhydrase inhibitor and a topical beta-adrenergic receptor blocking agent.
Dorzolamide hydrochloride is described chemically as: (4 S-trans)-4-(ethylamino)-5,6-dihydro-6-methyl-4 H- thieno[2,3- b ]thiopyran-2-sulfonamide 7,7-dioxide monohydrochloride. Dorzolamide hydrochloride is optically active. The specific rotation is:
|
|
25°C
|
|
|
[(alpha)] |
|
(C=1, water) = ~ -17°. |
|
|
405 nm
|
|
|
Its empirical formula is C10H16N2O4S3·HCl and its structural formula is:
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 nominal optical rotation of timolol maleate is:
|
|
25°C
|
|
|
[(alpha)] |
|
in 1N HCl (C=5) = -12.2° (-11.7° to -12.5°). |
|
|
405 nm
|
|
|
Its molecular formula is C13H24N4O3S·C4H4O4 and its structural formula is:
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.
COSOPT is supplied as a sterile, 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 COSOPT 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.
*Registered trademark of MERCK & CO., Inc.
|
