The present invention relates to a novel crystalline disodium pamidronate 3˜4 hydrate and a process for preparing it. More particularly, crystalline disodium pamidronate 3˜4 hydrate of the following formula I having the water content of 17.0˜20.0 wt % and being in the state of the mixture of trihydrate and tetrahydrate is prepared by neutralizing pamidronic acid with sodium compound, drying the formed disodium pamidronate, dissolving the disodium pamidronate in water, filtering sparingly soluble materials, allowing the filtrate to stand with stirring at normal temperature to form crystals, cooling and filtering the mixture to obtain crystals, and drying at the temperature of 75˜85° C. under normal pressure.
The novel disodium pamidronate 3˜4 hydrate according to the present invention is much more stable compound structurally than the known disodium pamidronate pentahydrate. When the compound is in storage or is used as pharmaceutical formulations, validity time can be prolonged and it can be formulated as convenient oral preparations such as soft capsule in addition to injections.
本发明涉及一种新的晶体二
钠帕米膦酸盐3~4
水合物及其制备方法。更具体地说,通过用
钠化合物中和
帕米膦酸,干燥形成的二
钠帕米膦酸盐,将其溶解在
水中,过滤出难溶物质,让滤液在常温下搅拌结晶,冷却并过滤混合物以获得晶体,然后在常压下以75~85℃的温度干燥,制备出
水含量为17.0~20.0重量%,处于三
水合物和四水合物混合状态的晶体二
钠帕米膦酸盐(式I)。本发明的新型二
钠帕米膦酸盐3~4
水合物在结构上比已知的五
水合物更为稳定。在存储或用作制药配方时,有效期可以延长,并且可以制成方便的口服制剂,例如软胶囊,除了注射剂。