设计了一种新型的递增pH值溶液(H3PO₄十冰HAc+H₃BU₃制成混合液，再另加不同量的 NaOH液),用于口服缓释制剂的体外溶出度实验。该溶液的pH植随溶出时间的增加而逐渐升高，与休 内胃肠液pH值的变化规律相近似。以布洛芬缓释制剂为药物模型．进行体外溶出度考察。实验结果表 明，递增pH值溶液能够反映出药物溶出度随溶液pH值的变化情况。

A new solution of increasing pH values progressively(H₃P0₄ + HAc +H₃B0₃+NaOH) was made and used in the dissolution test of oral sustained release preparation. With the increasing of dissolution time,the solution's pH values increased progressively and conformed to those,in the gastric and intestine juice.The dissolution test of ibuprofen sustained release preparation showed that the solution of increasing pH values progressively can reflect the changes of drug dissolution rate according to the pH values.