1972 年 92 巻 1 号 p. 32-36
Studies were made on interactions of β-cyclodextrin with six kinds of barbituric acid derivatives and thiopental. It was found by solubility analysis that complexes were formed between β-cyclodextrin and all the pharmaceuticals tested. Barbituric acid derivatives having a cyclic substituent at 5-position showed a higher degree of interaction with β-cyclodextrin than those having acyclic substituent. Thiopental, 2-thiobarbituric acid derivative formed a more stable complex with β-cyclodextrin than pentobarbital, which is a barbituric acid derivative and has the same substituent at 5-position as thiopental. Stability of aqueous preparations of sodium salts of these barbituric acid derivatives was examined and it was found that dissolved salts separated out gradually as free acids by absorption of atmospheric carbon dioxide and that chemical decomposition due to ring fission of the barbituric acid derivatives was practically negligible. Deposition of free barbituric acid derivatives from these solutions was retarded to some extent in the presence of β-cyclodextrin.