1988 年 36 巻 1 号 p. 345-353
In this study, the stability of bacampicillin hydrochloride (BAPC) suspension was measured to clarify the kinetics in a consentrated solution. Then, the time courses BAPC in suspension were examined in the neutral pH region and at 35°C. In this suspension, not only total BAPC, but also the dissolved BAPC were decreased with time. This result indicates that particles of BAPC precipitate from the solution with time, and the infrared (IR) spectrum of the precipitates suggested that they consisted of BAPC base. Furthermore, the degradation of BAPC in suspension was very much faster than that in solution. This acceleration of the degradation was due to the simultaneous degradation of the precipitated and the dissloved BAPC. In addition, the apparent first-order degradation rate constant of the precipitated particles was larger than that of the dissolved BAPC. Thus, the degradation of the solid seems to be accelerated by hydroxyl ion.