Hashizaki Kaname, Hoshii Yuto, Ikeuchi Kosuke, Imai Miko, Taguchi Hiroyuki, Goto Yukihiro, Fujii Makiko
Laboratory of Physical Chemistry, School of Pharmacy, Nihon University.
EKO Instruments Co., Ltd.
Chem Pharm Bull (Tokyo). 2021;69(11):1083-1087. doi: 10.1248/cpb.c21-00537.
Our aim was to determine the surface free energy (SFE) of semi-solid dosage forms (SSDFs) by establishing a reproducible method for measuring the contact angle of liquids to SSDFs. Four SSDFs were used: petrolatum, an oil/water (O/W) and a water/oil (W/O) cream, and an alcohol-based gel. The SSDFs were evenly spread on a glass slide, and the change in contact angle over time was measured by dropping water, glycerol, diiodomethane and n-hexadecane as the test liquids. Depending on the combination of test liquid and SSDF, the contact angle was either constant or decreased in an exponential manner. Contact angles may have decreased in an exponential manner because the reaction between the test liquid and the SSDF altered the interfacial tension between the two phases and changed the surface tension of the test liquid and the SFE of the SSDF. The contact angle of the test liquid to the SSDF could be determined reproducibly using the initial contact angle immediately after dropping the liquid on the SSDF as the contact angle before reaction. Using the obtained contact angles and the Owens-Wendt-Rabel-Kaelble equation, we calculated the SFE and its component for the SSDFs tested and found that the results reflect the physicochemical properties of SSDFs. Furthermore, the work of adhesion (W) of the SSDF to Yucatan micropig skin was calculated using the SFE for the SSDFs. Interestingly, the W values for all SSDFs tested were comparable.
我们的目的是通过建立一种可重复的方法来测量液体与半固体制剂（SSDFs）的接触角，从而确定半固体制剂的表面自由能（SFE）。使用了四种半固体制剂：凡士林、油包水（O/W）乳膏、水包油（W/O）乳膏和酒精基凝胶。将半固体制剂均匀地铺展在载玻片上，通过滴加水、甘油、二碘甲烷和正十六烷作为测试液体来测量接触角随时间的变化。根据测试液体和半固体制剂的组合，接触角要么保持恒定，要么呈指数下降。接触角可能呈指数下降，是因为测试液体与半固体制剂之间的反应改变了两相之间的界面张力，改变了测试液体的表面张力和半固体制剂的表面自由能。使用将液体滴加到半固体制剂上后立即得到的初始接触角作为反应前的接触角，可以可重复地确定测试液体与半固体制剂的接触角。利用获得的接触角和欧文斯-温德特-拉贝尔-凯尔布尔方程，我们计算了测试的半固体制剂的表面自由能及其组分，发现结果反映了半固体制剂的物理化学性质。此外，利用半固体制剂的表面自由能计算了半固体制剂与尤卡坦微型猪皮肤的粘附功（W）。有趣的是，所有测试的半固体制剂的W值相当。
