中和法制备水杨酸微晶

Microcrystal Preparation of Salicylic Acid by Neutralization Method

为增加水杨酸在各类制剂中的分散度，便于制备，提高疗效，采用酸碱中和法将其制成微晶。先将水杨酸与１ｍｏｌ／Ｌ氢氧化钠反应成盐溶解，然后用１ｍｏｌ／Ｌ盐酸中和析出微晶。所得微晶呈针状，色白，膨松，在电镜下测得平均粒径为１６μｍ。各项理化标准符合中国药典１９９５年版规定。本法微晶得率为９８％。

Salicylic acid formed sodium salicylate and dissolved, 1 mol/L HCl was added slowly to the solution of sodium salycylate so as to neutralize the NaOH in solution and to obtain microcrystal of salicylic acid. The microcrystal obtained was white and loose needle, the mean diam of microcrystal determined under electromicroscope was 16 μm and its physical and chemical indexes complied with Chinese pharmacopoeia. The rate of microcrystal was 98% by this method