(3R,4R)-3-ethyl-4-[(3-methylimidazol-4-yl)methyl]oxolan-2-one; Pilocarpine Nitrate - Impurity A (EP/BP); (3R,4R)-3-Ethyl-4-[(1-methyl-1H-imidazol-5-yl)methyl]dihydrofuran-2(3H)-one; (3R,4R)-3-Ethyldihydro-4-[(1-methyl-1H-imidazol-5-yl)methyl]-2(3H)-furanone; (3R-trans)-3-Ethyldihydro-4-[(1-methyl-1H-imidazol-5-yl)methyl]-2(3H)-furanone; 3-Isopilocarpine; (+)-Isopilocarpine; β-Pilocarpine; lsopilocarpine, (3R ,4R )-3-Ethyl-4-[(1-methyl-1H -imidazol-5-yl)methyl]dihydrofuran-2(3H )-one (USP)