Otsuka M, Ohtani H, Kaneniwa N, Higuchi S
Kobe Women's College of Pharmacy, Japan.
J Pharm Pharmacol. 1991 Mar;43(3):148-53. doi: 10.1111/j.2042-7158.1991.tb06656.x.
Isomerization during grinding of solid-state 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 (20 degrees C). The crystallinity of 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 obtained from the specific rotation measured by using angular rotation spectrophotometry. The crystalline lactose samples were transformed into non-crystalline solids by mechanical stress during grinding. After grinding, the water content of all ground lactose samples increased, and the samples had about 2 mol water per lactose after 10 h grinding. After 10 h grinding of alpha-monohydrate and alpha-anhydrate, 10 and 15%, respectively, of alpha-lactose was transformed into beta-lactose by the mechanical treatment. After 10 h grinding of beta-lactose, 20% of beta-lactose was transformed into alpha-lactose. The results suggest that crystalline lactose was transformed into a non-crystalline solid, and water was adsorbed on the non-crystalline lactose. The non-crystalline solids of alpha- or beta-lactose were then transformed into their counterparts by the mechanochemical effects of grinding.
研究了乳糖固态α-一水合物、α-无水合物和β-无水合物研磨过程中的异构化现象。样品在玛瑙离心球磨机中于室温（20℃）下以270转/分钟的速度研磨。通过粉末X射线衍射图谱，采用赫尔曼斯方法测量研磨后乳糖的结晶度。通过使用旋光分光光度法测量的比旋光度获得研磨后乳糖的α-和β-乳糖含量。在研磨过程中，结晶乳糖样品通过机械应力转变为非晶态固体。研磨后，所有研磨乳糖样品的含水量增加，研磨10小时后，样品每摩尔乳糖含有约2摩尔水。α-一水合物和α-无水合物研磨10小时后，分别有10%和15%的α-乳糖通过机械处理转变为β-乳糖。β-乳糖研磨10小时后，20%的β-乳糖转变为α-乳糖。结果表明，结晶乳糖转变为非晶态固体，水吸附在非晶态乳糖上。然后，α-或β-乳糖的非晶态固体通过研磨的机械化学作用转变为其对应物。
