Nenoff P, Haustein U F
Department of Dermatology, University of Leipzig, Germany.
Skin Pharmacol. 1997;10(5-6):275-80.
The in vitro antifungal activity of the new hydroxypyridone antimycotic rilopirox has been evaluated against 29 separate clinical isolates of Malassezia (M.) furfur obtained from patients with pityriasis versicolor, seborrhoeic dermatitis or dandruff. Minimum inhibitory concentrations (MICs) of rilopirox were measured by the agar dilution technique and, in comparison, by a recently described microdilution method with colorimetric detection of the MIC end points. Rilopirox was found to be able to inhibit growth of all clinical yeast isolates. For the investigated M. furfur strains MIC values from 12.5 to 50 micrograms ml-1 with a median of 25 micrograms ml-1 were determined by the agar dilution method. Using the microdilution technique, MIC values between 16 and 128 micrograms ml-1 (median 32 micrograms ml-1) were found for the M furfur isolates. It has to be taken into account that with a 0.3% solution concentrations of 300,000 micrograms ml-1 are applied to the skin. Furthermore, due to its extreme low penetration rilopirox is long-term available in the skin in inhibiting concentrations. In comparison with rilopirox, the in vitro susceptibility of M. furfur against the systemically applicable triazole antimycotic itraconazole and clotrimazole, an established topical antifungal, was tested. As expected, low MIC values for these azoles were found by the agar dilution method. The median of the MIC of M. furfur was 0.1 microgram ml-1 for itraconazole, and 6.25 micrograms ml-1 for clotrimazole. The inhibitory effectivity of rilopirox against clinical isolates of M. furfur seems to justify its therapeutic evaluation in clinical trials. This new antifungal may be a useful alternative not only in pityriasis versicolor but also in seborrhoeic dermatitis due to the growth inhibition of M. furfur.
新型羟基吡啶酮抗真菌药利拉萘酯对从花斑癣、脂溢性皮炎或头皮屑患者中分离出的29株糠秕马拉色菌临床分离株的体外抗真菌活性进行了评估。利拉萘酯的最低抑菌浓度（MIC）通过琼脂稀释技术测定，并且作为比较，还采用了最近描述的通过比色法检测MIC终点的微量稀释法。发现利拉萘酯能够抑制所有临床酵母分离株的生长。对于所研究的糠秕马拉色菌菌株，通过琼脂稀释法测定的MIC值为12.5至50微克/毫升，中位数为25微克/毫升。使用微量稀释技术，糠秕马拉色菌分离株的MIC值在16至128微克/毫升之间（中位数为32微克/毫升）。必须考虑到，使用0.3%的溶液时，皮肤表面的应用浓度为300,000微克/毫升。此外，由于其极低的渗透率，利拉萘酯在皮肤中能以抑制浓度长期存在。与利拉萘酯相比，测试了糠秕马拉色菌对可全身应用的三唑类抗真菌药伊曲康唑和已确立的局部抗真菌药克霉唑的体外敏感性。正如预期的那样，通过琼脂稀释法发现这些唑类药物的MIC值较低。糠秕马拉色菌对伊曲康唑的MIC中位数为0.1微克/毫升，对克霉唑的MIC中位数为6.25微克/毫升。利拉萘酯对糠秕马拉色菌临床分离株的抑制有效性似乎证明了其在临床试验中的治疗评估价值。这种新型抗真菌药不仅在花斑癣中，而且由于对糠秕马拉色菌的生长抑制作用，在脂溢性皮炎中可能也是一种有用的替代药物。
