Otsuka M, Ohtani H, Otsuka K, Kaneniwa N
School of Pharmaceutical Sciences, Showa University, Tokyo, Japan.
J Pharm Pharmacol. 1993 Jan;45(1):2-5. doi: 10.1111/j.2042-7158.1993.tb03668.x.
The effect of humidity on isomerization during grinding of alpha-monohydrate, alpha-anhydrate and beta-anhydrate of lactose was investigated. Samples were ground in an agate centrifugal ball mill at 270 rev min-1 at room temperature (21 degrees C) and at 5 and 60% relative humidity. Crystallinity of the ground lactose was measured by Hermans' method from the powder X-ray diffraction profiles. The alpha- and beta-lactose content of the ground lactose was measured by using angular rotation spectrophotometry. The crystalline lactose samples were transformed into noncrystalline solids by mechanical stress during grinding. After grinding, the adsorbed water content of all ground lactose samples increased, and the isomerized amount increased with increase of the water content during grinding at 5 and 60% relative humidity. The results suggest that the isomerization rate of alpha-monohydrate during grinding may depend on the crystallinity, but those of alpha- and beta-anhydrate depend on the content of adsorbed water.
研究了湿度对乳糖α-一水合物、α-无水合物和β-无水合物研磨过程中异构化的影响。样品在玛瑙离心球磨机中于室温（21℃）、转速为270转/分钟、相对湿度分别为5%和60%的条件下进行研磨。通过粉末X射线衍射图谱，采用赫尔曼斯方法测定研磨后乳糖的结晶度。使用旋光分光光度法测定研磨后乳糖的α-和β-乳糖含量。在研磨过程中，结晶乳糖样品因机械应力转变为非晶态固体。研磨后，所有研磨乳糖样品的吸附水含量增加，且在相对湿度为5%和60%的研磨过程中，异构化量随含水量增加而增加。结果表明，α-一水合物在研磨过程中的异构化速率可能取决于结晶度，而α-无水合物和β-无水合物的异构化速率则取决于吸附水含量。
