Ramipril methyl ester is the proline-containing impurity of ramipril, labelled as ramipril Impurity A. It is one of the four qualified impurities. Impurity A is the manufacture process impurity. Ramipril is an angiotensin-converting enzyme (ACE) inhibitor, used to treat high blood pressure (hypertension) and congestive heart failure.

(2R,3AR,6AR)-1-((2S)-2-(((1S)-1-(ethoxycarbonyl)-3-phenylpropyl)amino)propanoyl)octahydrocyclopenta(B)pyrole-2-carboxylic acid is one of many isomers of ramipril and is known as Impurity N. Ramipril is an angiotensin-converting enzyme (ACE) inhibitor, used to treat high blood pressure (hypertension) and congestive heart failure.

Toluene is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a CH3 group attached to a phenyl group. The major use of toluene is as a mixture added to gasoline to improve octane ratings. Toluene is also usedto produce benzene and as a solvent in paints, coatings, synthetic fragrances, adhesives, inks, and cleaningagents. Toluene is also used in the production of polymers used to make nylon, plastic soda bottles, andpolyurethanes and for pharmaceuticals, dyes, cosmetic nail products, and the synthesis of organicchemicals. The CNS is the primary target organ for toluene toxicity in both humans and animals for acute and chronicexposures. CNS dysfunction (which is often reversible) and narcosis have been frequently observed inhumans acutely exposed to low or moderate levels of toluene by inhalation; symptoms include fatigue,sleepiness, headaches, and nausea. CNS depression and death have occurred at higher levels of exposure. Toluene is used in veterinary medicine as a treatment for various parasites in dogs and cats. It is used for the removal of ascarids (Toxocara canis and Toxascaris leonina) and hookworms (Ancylostoma caninum and Uncinaria stenocephala) and as an aid in removing tapeworms (Taenia pisiformis, Dipylidium caninum, and Echinococcus granulosus) from dogs and cats.

Ramipril (sold under the brand name Altace ) is a prodrug belonging to the angiotensin-converting enzyme (ACE) inhibitors. It is metabolized to ramiprilat in the liver and, to a lesser extent, kidneys. Ramiprilat is a potent, competitive inhibitor of ACE, the enzyme responsible for the conversion of angiotensin I (ATI) to angiotensin II (ATII). ATII regulates blood pressure and is a key component of the renin-angiotensin-aldosterone system (RAAS). Ramipril is indicated for the treatment of hypertension, to lower blood pressure; also used to reduce the risk of myocardial infarction, stroke, or death from cardiovascular causes; in addition, this drug is used to reduce the rate of death, myocardial infarction and stroke in individuals at high risk of cardiovascular events.