Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, Atlanta, GA, USA.
GSK Consumer Healthcare, Warren, NJ, USA.
Pharm Dev Technol. 2021 Apr;26(4):403-411. doi: 10.1080/10837450.2021.1881113. Epub 2021 Feb 4.
Urea has been incorporated into several topical ungual formulations to hydrate and soften the nail plate. In this study, we employed various characterization techniques (visual observation, scanning electron microscopy, measurement of thickness, transonychial water loss, nail electrical resistance, and mechanical study) to investigate the effect of urea concentration on the hydration of bovine hoof membranes - an model of infected human nails. We obtained inconsistent results in the thickness, transonychial water loss, nail electrical resistance, and scanning electron microscopy studies. In the mechanical study using a modified Texture Analyzer method, we reported an inverse and linear correlation between urea concentrations in the formulations and the force required to puncture the treated membrane ( = 0.9582, ≥ 8). As the urea concentration decreased from 4x to 2x, 1x, and 0x % w/w, the puncture force increased significantly from 0.47 ± 0.07 to 0.77 ± 0.07, 0.91 ± 0.09, and 1.33 ± 0.26 N, respectively ( 0.05). Thus, urea provided a positive softening effect on the membranes and the puncture force could indicate the urea level in topical formulations. In this study, we provided a novel, efficient, and reliable tool to evaluate the hydration level and physical properties of bovine hoof membranes.
尿素已被纳入几种局部指甲制剂中，以滋润和软化指甲板。在这项研究中，我们采用了各种表征技术（肉眼观察、扫描电子显微镜、厚度测量、经皮水分丢失、指甲电阻和机械研究）来研究尿素浓度对牛蹄膜水化的影响 - 一种感染人类指甲的模型。我们在厚度、经皮水分丢失、指甲电阻和扫描电子显微镜研究中得到了不一致的结果。在使用改良的 Texture Analyzer 方法进行的机械研究中，我们报告了制剂中尿素浓度与刺穿处理后的膜所需力之间存在反线性相关性（= 0.9582，≥8）。随着尿素浓度从 4x 降至 2x、1x 和 0x % w/w，刺穿力从 0.47 ± 0.07 显著增加至 0.77 ± 0.07、0.91 ± 0.09 和 1.33 ± 0.26 N，分别（ 0.05）。因此，尿素对膜提供了积极的软化效果，而刺穿力可以指示局部制剂中的尿素水平。在这项研究中，我们提供了一种新颖、高效和可靠的工具来评估牛蹄膜的水化水平和物理性质。
