Stieger N, Joubert A, Liebenberg W
Pharmazie. 2017 Aug 1;72(8):447-448. doi: 10.1691/ph.2017.7035.
Water and water vapor are the bane of amorphous drug stability, both in storage and after administration. As is to be expected, crystallization of amorphous azithromycin did occur when exposed to water as dissolution medium. However, experimental results showed that, although solution-mediated phase transformation had occurred, it was not a rapid process for this drug. It is considered to be an advantageous characteristic of amorphous azithromycin and likely due to the high molecular mass (748.984 g/mol) and complex structure necessitating more energy for transformations to occur. A high apparent solubility is maintained for a considerable period of time, potentially rendering a higher percentage of this BCS Class II drug available for absorption when administered orally.
无论是在储存过程中还是给药后，水和水蒸气都是无定形药物稳定性的克星。不出所料，当以水作为溶解介质时，无定形阿奇霉素确实发生了结晶。然而，实验结果表明，尽管发生了溶液介导的相变，但对这种药物来说这并不是一个快速的过程。这被认为是无定形阿奇霉素的一个有利特性，可能是由于其高分子量（748.984 g/mol）和复杂的结构，使得转变需要更多能量。在相当长的一段时间内保持较高的表观溶解度，这可能使这种BCS II类药物在口服给药时可供吸收的百分比更高。
