Enalapril maleate

Some workers avoid delay. Pai)adium-on-carbon was used effectively for the reductive amination of ethyl 2-oxo-4-phenyl butanoate with L-alanyl-L-proline in a synthesis of the antihyperlensive, enalapril maleate. SchifTs base formation and reduction were carried out in a single step as Schiff bases of a-amino acids and esters are known to be susceptible to racemization. To a solution of 4,54 g ethyl 2-oxO 4-phenylbutanoate and 1.86 g L-alanyl-L-proline was added 16 g 4A molecular sieve and 1.0 g 10% Pd-on-C The mixture was hydrogenated for 15 hr at room temperature and 40 psig H2. Excess a-keto ester was required as reduction to the a-hydroxy ester was a serious side reaction. The yield was 77% with a diastereomeric ratio of 62 38 (SSS RSS)((55). 

Hydroserpine 2 Tablets—hydrochbrothiazide, reserpine Hyzaar—hydrochlorothiazide, losartan potassium Inderide—hydrochlorotliiazide, propranolol HC1 Inderide LA—hydrochlorotliiazide, propranolol HC1 Lexxel Extended-Release—enalapril maleate, felodipine Lopressor—hydrochlorothiazide, metoprolol Lotensin HCT—hydrochlorothiazide, benazepril Lotrel—amlodopine, benazepril... 

Teczem EIxtended-Release—diltiazem maleate, enalapril maleate... 

Uniretic—hydrochlorotliiazide, moexipril HC1 Vaseretic—hydrochlorotliiazide, enalapril maleate Zestoretic—hydrochlorotliiazide, lisinopril Ziac—hydrochlorothiazide, bisoprolol fumarate... 

In some instances, distinct polymorphic forms can be isolated that do not interconvert when suspended in a solvent system, but that also do not exhibit differences in intrinsic dissolution rates. One such example is enalapril maleate, which exists in two bioequivalent polymorphic forms of equal dissolution rate [139], and therefore of equal free energy. When solution calorimetry was used to study the system, it was found that the enthalpy difference between the two forms was very small. The difference in heats of solution of the two polymorphic forms obtained in methanol was found to be 0.51 kcal/mol, while the analogous difference obtained in acetone was 0.69 kcal/mol. These results obtained in two different solvent systems are probably equal to within experimental error. It may be concluded that the small difference in lattice enthalpies (AH) between the two forms is compensated by an almost equal and opposite small difference in the entropy term (-T AS), so that the difference in free energy (AG) is not sufficient to lead to observable differences in either dissolution rate or equilibrium solubility. The bioequivalence of the two polymorphs of enalapril maleate is therefore easily explained thermodynamically. 

Al-Omari, M.M., Abelah, M.K., Badwan, A.A., and Aaber, A.M., Effect of drug matrix on the stability of enalapril maleate in tablet formulation, ]. Pharm. Biomed. Anal., 25, 893, 2001. 

For conversion from IV to oral therapy, the recommended initial dose of enalapril maleate tablets for patients who have responded to 0.625 mg enalaprilat every 6 hours is 2.5 mg once a day with subsequent dosage adjustment as needed. 

USAN Enalapril maleate Trade name Vasotec Merck Co. 

P.K. Shiromani and J.F. Bavitz, Effect of moisture on the physical and chemical stability of granulations and tablets of the angiotensin converting enzyme inhibitor, enalapril maleate. Drug Dev. Ind. Pharm., 12 (1986) 2467. 

Angiotensin converting ENZYME (ACE) inhibitors captopril cilazapril enalapril maleate fosinopril sodium lisinopril... 

Enalapril maleate is an orally active angiotensin converting enzyme (ACE) inhibitor, it lowers peripheral vascular resistance without causing an increase in heart rate. The maleate salt (enalapril) allows better absorption after oral administration. It is an ideal drug for hypertensive patients who are intolerant to beta-blocker therapy. It also shows promise in the treatment of congestive heart failure. Following oral adminishation, enalapril is rapidly absorbed and hydrolysed to... 

Calcium channel blockers, including diltiazem (Cardizem SR, Dilacor XR, Tiazac), nicardipine (Cardene), amlodipine (Norvasc), felodipine (Plendil), and enalapril maleate-felodipine ER (Lexxel). 

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