Hasuko Masayuki, Toga Tetsuo, Tsunemitsu Toshiya, Matsumoto Takahiro, Koga Hiroyasu, Hirano Hirofumi, Tsuboi Ryoji
Nihon Nohyaku Co., Ltd.
Med Mycol J. 2016;57(1):J7-12. doi: 10.3314/mmj.57.J7.
Luliconazole (LLCZ), an imidazole derivative with a broad spectrum of potent antifungal activity especially for T. rubrum and T. mentagrophytes, is under development as a new drug for treatment of tinea unguium. It is well known that curative effect of an antifungal agent in dermatophytosis is affected by the pharmacokinetics of an agent at the infection loci as well as its antifungal activity, but there is no report about the affinity of LLCZ to nail keratin. We studied LLCZ affinity to keratin powder prepared from healthy human nail and porcine hoof. The LLCZ adsorbed to keratin preparations was washed with phosphate buffer, and its concentration in the buffer supernatant was measured by HPLC. Antifungal titer of the supernatant was also biologically confirmed by disk diffusion assay. Adsorption rate of LLCZ was 80% or more, and LLCZ was gradually liberated into washing buffer. Cumulative liberation rate in 10 times repeated washing against initially adsorbed drug amount was 47.4% for keratin from human nail and was either 52.5% or 50.8% (depending on the LLCZ concentration) for keratin from porcine hoof. The supernatant showed antifungal potential to T. rubrum. These results indicate that LLCZ applied to the nail surface is fully adsorbed to nail keratin and gradually liberated from it. The nail keratin could function as drug reservoir to supply biologically active LLCZ to the nail tissue region of infection loci. The LLCZ delivered to the loci would exert its antifungal potential on tinea unguium. This study also suggests the versatility of porcine hoof powder as an alternative to human nail keratin preparation for non-clinical study.
卢立康唑（LLCZ）是一种咪唑衍生物，具有广谱强效抗真菌活性，尤其对红色毛癣菌和须癣毛癣菌有效，目前正作为一种治疗甲癣的新药进行研发。众所周知，抗真菌药物在皮肤癣菌病中的疗效受药物在感染部位的药代动力学及其抗真菌活性影响，但尚无关于LLCZ与指甲角蛋白亲和力的报道。我们研究了LLCZ对从健康人指甲和猪蹄制备的角蛋白粉末的亲和力。用磷酸盐缓冲液洗涤吸附在角蛋白制剂上的LLCZ，并用高效液相色谱法测定缓冲液上清液中其浓度。还通过纸片扩散法从生物学上确认了上清液的抗真菌效价。LLCZ的吸附率达80%或更高，且LLCZ逐渐释放到洗涤缓冲液中。针对最初吸附的药量进行10次重复洗涤时，人指甲角蛋白的累积释放率为47.4%，猪蹄角蛋白的累积释放率为52.5%或50.8%（取决于LLCZ浓度）。上清液对红色毛癣菌显示出抗真菌潜力。这些结果表明，应用于指甲表面的LLCZ能完全吸附到指甲角蛋白上，并逐渐从其上释放出来。指甲角蛋白可作为药物储库，向感染部位的指甲组织区域供应具有生物活性的LLCZ。输送到该部位的LLCZ将对甲癣发挥其抗真菌潜力。本研究还表明，猪蹄粉作为人指甲角蛋白制剂的替代品用于非临床研究具有通用性。
