Solubilization of amobarbital by mechanical treatment in the presence of diluents.

Abstract

Amobarbital was ball-milled, triturated, mortar-ground or stamp-milled in the absence or in the presence of various kinds of diluents, and the variation of solubility of amobarbital from these samples in the KH2PO4-Na2HPO4 buffer solution of pH of 6.0 at 30°was investigated. It was suggested from the results of the elemental analysis, measurement of the mass spectra and the infrared spectra, and the chemical analysis by thin-layer chromatography and gas chromatography that amobarbital in the mechanically treated mixtures of precipitated silica or carbon black was hydrolyzed by the addition of water. It was also suggested that amobarbital decomposed or formed complex by ball-milling in the presence of potato starch. But, it was considered that decomposition of amobarbital by the mechanical treatment in the absence and in the presence of the other diluents was negligible. Solubility of amobarbital in the buffer solution increased by mechanical treatment in the presence of methyl cellulose or hydroxypropyl cellulose. It was considered that solubilization of amobarbital was related to the decrease in the intensity of the signals of amobarbital in the X-ray diffraction diagrams and dropping of the melting point of amobarbital by mechanical treatment in the presence of the diluent. It was also considered that solubilization of amobarbital was due to the interaction with the diluent in the suspension caused by mechanical treatment and to the kind of the crystal structure of amobarbital formed by recrystalization after dissolution.