Quinapril and hydrochlorothiazide tablets are fixed-combination tablets that combine an angiotensin-converting enzyme (ACE) inhibitor, quinapril hydrochloride, and a thiazide diuretic, hydrochlorothiazide.
Quinapril hydrochloride is chemically described as [3S-[2[R*(R*)], 3R*]]-2-[2-[[1-(ethoxycarbonyl)-3-phenylpropyl] amino]-1-oxopropyl]-1,2,3,4-tetrahydro-3-isoquinolinecarboxylic acid, monohydrochloride. Its empirical formula is C25H30N2O5. HCl and its structural formula is:
Quinapril hydrochloride is a white to off-white amorphous powder that is freely soluble in aqueous solvents.
Hydrochlorothiazide is chemically described as: 6-Chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide. Its empirical formula is C7H8ClN3O4S2 and its structural formula is:
Hydrochlorothiazide is a white to off-white, crystalline powder which is slightly soluble in water but freely soluble in sodium hydroxide solution.
Quinapril and hydrochlorothiazide tablets are available for oral use as fixed combination tablets in three strengths of quinapril with hydrochlorothiazide: 10 mg (equivalent to 10.832 mg quinapril hydrochloride) with 12.5 mg (quinapril and hydrochlorothiazide tablets 10/12.5), 20 mg (equivalent to 21.664 mg quinapril hydrochloride) with 12.5 mg (quinapril and hydrochlorothiazide tablets 20/12.5), and 20 mg (equivalent to 21.664 mg quinapril hydrochloride) with 25 mg (quinapril and hydrochlorothiazide tablets 20/25). Inactive ingredients: candelilla wax, crospovidone, hydroxypropyl cellulose, hypromellose, iron oxide red, iron oxide yellow, lactose, magnesium carbonate, magnesium stearate, polyethylene glycol, povidone, and titanium dioxide.