abstract |
The invention concerns a levulinic acid addition salt of the antihypertensive agent 4-amino-6,7-dimethoxy-2-[4-(5-methylthio-1,3,4-oxadiazole-2-carbonyl]p iperazin-1-yl)quinazoline in which the base to acid mole ratio is 1 to from 1.25-1.35. The salt is characterized in having improved water solubility and stability compared to the levulinate salt having a 1:1 ratio of base to acid. |