合成高分子化合物と医薬品との相互作用に関する研究(第4報) : スチレン無水マレイン酸共重合体とバルビツール酸誘導体, ヒドロキシ安息香酸誘導体およびキサンチン誘導体との相互作用

抄録

As a part of a program concerning complex formation among pharmaceuticals, investigation was made on the interaction between styrene-maleic anhydride copolymer (SMA) and the following 12 pharmaceutical compounds in ethylene dichloride solution, using a solubility method ; hydroxybenzoic acids (ortho, meta, and para isomers), p-aminosalicylic acid, methyl and ethyl p-hydroxybenzoates, caffeine, theobromine, theophylline, barbituric acid, barbital, and allobarbital. In the hydroxybenzoic acid series, p-hydroxybenzoic acid exhibited the greatest binding to SMA, followed by the meta and ortho isomers. p-Aminosalicylic acid was more reactive than salicylic acid because of the presence of the amino grouping. Elimination of the acidic hydrogen atom from p-hydroxybenzoic acid by esterification, as in methyl and ethyl p-hydroxybenzoates, reduced the ability of the molecule to participate in complex formation. A comparison of three barbiturates has shown that greater the aliphatic character of the disubstitution at the 5-position of barbituric acid, the less was their affinity to SMA. This may be due, in part, to a decrease in polarity of the molecule or to an increase in the steric factor of the substituent. Theophylline and theobromine were also found to bind with SMA, but no evidence of binding was detected between caffeine and SMA. The ability of complexation probably rests on the relative proton-donating properties of these xanthine derivatives. The significance of these results with respect to possible mechanisms of complex formation is discussed.